• Journal of Bio-Environment Control
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• v.31 no.4
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• pp.401-408
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• 2022

As research on a controlled environment system based on crop growth environment sensing for sustainable production of horticultural crops and its industrial use has been important, research on how to properly utilize soil moisture sensors for outdoor cultivation is being actively conducted. This experiment was conducted to suggest the proper method of utilizing the TEROS 12, an FDR (frequency domain reflectometry) sensor, which is frequently used in industry and research fields, for each orchard soil in three regions in Korea. We collected soils from each orchard where fruit trees were grown, investigated the soil characteristics and soil water retention curve, and compared TEROS 12 sensor calibration equations to correlate the sensor output to the corresponding soil volumetric water content through linear and cubic regressions for each soil sample. The estimated value from the calibration equation provided by the manufacturer was also compared. The soil collected from all three orchards showed different soil characteristics and volumetric water content values by each soil water retention level across the soil samples. In addition, the cubic calibration equation for TEROS 12 sensor showed the highest coefficient of determination higher than 0.95, and the lowest RMSE for all soil samples. When estimating volumetric water contents from TEROS 12 sensor output using the calibration equation provided by the manufacturer, their calculated volumetric water contents were lower than the actual volumetric water contents, with the difference up to 0.09-0.17 m³·m^-3 depending on the soil samples, indicating an appropriate calibration for each soil should be preceded before FDR sensor utilization. Also, there was a difference in the range of soil volumetric water content corresponding to the soil water retention levels across the soil samples, suggesting that the soil water retention information should be required to properly interpret the volumetric water content value of the soil. Moreover, soil with a high content of sand had a relatively narrow range of volumetric water contents for irrigation, thus reducing the accuracy of an FDR sensor measurement. In conclusion, analyzing soil water retention characteristics of the target soil and the soil-specific calibration would be necessary to properly quantify the soil water status and determine their adequate irrigation point using an FDR sensor.

• Korean Journal of Remote Sensing
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• v.38 no.6_1
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• pp.1371-1383
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• 2022

In this study, the amount of coal waste dump was calculated using six Digital Elevation Models (DEMs) produced between 2006 and 2018 in Jangseong-dong, Taebaek-si, Gangwon-do, and the subsidence was observed by applying the Persistent Scatterer Interferometric SAR (PSInSAR) technique on the Sentinel-1 SAR images. As a result of depositing activities using DEMs, a total of 1,668,980 m³ of coal waste was deposited over a period of about 12 years from 2006 to 2018. The observed subsidence rate from PSInSAR was -32.3 mm/yr and -40.2 mm/yr from the ascending and descending orbits, respectively. As the thickness of the waste pile increased, the rate of subsidence increased, and the more recent the completion of the deposit, the faster the subsidence tended to occur. The subsidence rates from the ascending and descending orbits were converted to vertical and horizontal east-west components, and 22 random reference points were set to compare the subsidence rate, the waste rock thickness, and the time of depositing completion. As a result, the subsidence rate of the reference point tended to increase as the thickness of the waste became thicker, similar to the PSInSAR results in relation to the waste thickness. On the other hand, there was no clear correlation between the completion time of the deposits and the rate Of subsidence at the reference points. This is because the time of completion of the deposits at all but 5 of the 22 reference points was too biased in 2010 and the correlation analysis was meaningless. As in this study, the use of DEM and PSInSAR is expected to be an effective alternative to compensate for the lack of field data in the safety management of coal waste deposits.

• 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 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.

• The Journal of Korean Academy of Sensory Integration
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• v.20 no.2
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• pp.11-21
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• 2022

Objective : This study examined the test-retest reliability and interrater reliability of the Sensory Processing Scale for Children (SPS-C). Method : Senventy primary caregivers of children with sensory processing difficulties and 3 years old participated in the study. The subjects were recruited through child development centers, welfare centers, and acquaintances located in Seoul, Gyeonggi-do, Busan, and Gyeongsang-do. The test-retest reliability verification targeted 20 main caregivers of children with difficulty in sensory processing. Re-evaluation was performed within 7 to 14 days after the initial evaluation, and Pearson's correlation coefficient was used to confirm the relevance between the two time points, and the Intraclass correlation coefficient was used to confirm the degree of agreement. The interrater reliability verification was conducted with 18 primary caregivers and 18 subsidiary caregivers of children with sensory processing difficulties. Each caregiver evaluated the same child, and the Intraclass correlation coefficient was used to confirm the agreement between the two sets of caregivers. Results : The test-retest reliability was Pearson's correlation coefficient r=.914 and intraclass correlation coefficient ICC=.939, indicating a high level of relevance and agreement. The interrater reliability was an Intraclass correlation coefficient ICC=.727, which showed a moderate level of agreement, but the tactile area (ICC=.455) and proprioceptive area (ICC=.439) were not statistically significant and showed a low degree of agreement. Conclusion : Through this study, it was confirmed that the children's Sensory Processing Scale for Children (SPS-C) is a stable evaluation tool with test-retest reliability and interrater reliability verified, and it will be able to provide help in standardization studies for future clinical use.

• Journal of Food Hygiene and Safety
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• v.37 no.5
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• pp.310-316
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• 2022

In this study, we compared the microbial reduction effects of drying, hot water, and microwave sterilization in scourers and dishcloths to suggest a most suitable sterilization method. Three scourer types (silver, copper, and mesh) were used, and three dishcloth types (silver, bamboo, and cotton) were used. Drying time dependent reduction in Escherichia coli was high in silver and copper scourers, but minimal bacterial reduction was obtained against Bacillus cereus in all scourers and dishcloths. In scourers, E. coli was not detected after ≥30 s of hot water sterilization at 77℃, and B. cereus was not detected after ≥60 s of hot water sterilization at 100℃. In dishcloths, E. coli was not detected after hot water sterilization at 77℃ for ≥30 s, but B. cereus was detected after hot water sterilization at 100℃ for ≥60 s. In scourers, E. coli was not detected after microwave sterilization at 700 W for 3 min, but B. cereus was detected. In dishcloths, E. coli was not detected after microwave sterilization with 700 W for ≥1 min, but B. cereus was detected in the cotton dishcloth even after sterilization for 3 min. In conclusion, the use of antimicrobial scourers (silver and copper) and dishcloths (silver and bamboo) are not sufficient to reduce the microbial contamination. The guideline provided by the Ministry of Food and Drug Safety suggesting dishcloth sterilization via hot water at 100℃ for 30 s was also found to be insufficient. Based on our research, we suggest that the most effective methods of microbial management are submerging scourers in hot water at 100℃ for ≥1 min, and sterilizing dishcloths for ≥3 min using a 700 W microwave.

• Journal of the Korean Orthopaedic Association
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• v.56 no.3
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• pp.253-260
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• 2021

Purpose: The least constrained prosthesis is generally recommended in primary total knee arthroplasty (TKA). Nevertheless, a varus/valgus constrained (VVC) prosthesis should be implanted when a semi-constrained prosthesis is not good for adequate stability, especially in the coronal plane. In domestic situations, however, the VVC prosthesis could not always be prepared for every primary TKA case. Therefore, it is sometimes impractical to use a VVC prosthesis for unsual unstable situations. This study provides information for preparing VVC prostheses in the preoperative planning of primary TKA through an analysis of primary VVC TKA cases. Materials and Methods: This study reviewed 1,797 primary TKAs, performed between May 2003 and February 2016. The reasons for requiring VVC prosthesis and the preoperative conditions in 29 TKAs that underwent primary TKA with a VVC prosthesis were analyzed retrospectively. Results: In primary TKA, 29 cases (1.6%) in 27 patients (6 male and 21 female) used VVC prosthesis. Two patients underwent a VVC prosthesis on both knees. The mean age of the patients was 63.4 years old (34-79 years). The mean flexion contracture was 16.2° (-20°-90°), and the mean angle of great flexion was 111.7° (35°-145°). The situations requiring a VVC prosthesis were severe valgus deformity in 10 knees, knee stiffness requiring extensive soft tissue release in 10 knees, previously injured collateral ligaments in five knees, and distal femoral bone defect due to avascular necrosis in four knees. The mean tibiofemoral angle was 25.7° (21°-43°) in 10 cases with a valgus deformity. The mean flexion contracture was 37.5° (20°-90°), and the mean range of motion was 48.5° (10°-70°) in 10 cases with knee stiffness. Conclusion: The preparation of VVC prosthesis is recommended, even for primary TKA in cases of severe valgus deformity (tibiofemoral angle>20°), stiff knee (the range of motion: less than 70° with more than 20° flexion contracture), and the cases with a previous collateral ligament injury. This information will help in the preparation of adequate TKA prostheses for unusual unstable situations.

• Journal of the Korean Orthopaedic Association
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• v.56 no.5
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• pp.398-403
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• 2021

Purpose: A biopsy is needed to diagnose soft tissue tumors. However, it is extremely difficult to pinpoint the site of a tumor due to the heterogeneity of sarcomas. Thus, even when an open biopsy is conducted, it is difficult to diagnose a soft tissue tumor. In such cases, an ultrasound (US)-guided biopsy is used to improve the diagnostic accuracy. This study evaluated the accuracy of US-guided biopsy for a diagnosis of soft tissue tumors found initially in a magnetic resonance (MR) perfusion and assessed the availability of positron emission tomography-computed tomography (PET-CT) for a diagnosis of soft tissue tumors. Materials and Methods: From January 2014 to December 2018, the US-guided biopsy was performed on 152 patients with a suspected soft tissue tumor found in an MR perfusion and 86 cases were definitively diagnosed with a soft tissue tumor. The accuracy of the US-guided biopsy was assessed retrospectively. Among the 86 cases, only MR perfusion was used before the biopsy in 50 cases, while both MR perfusion and PET-CT was conducted on 36 cases. The accuracy was analyzed to determine if the PET-CT could improve the precision of a biopsy. Results: From 86 cases, 34 out of 50 cases, in which only MR perfusion had been conducted, matched the result of the definitive diagnosis and the US-guided biopsy. 32 out of 36 cases, in which both PET-CT and MR perfusion were conducted, matched the definitive diagnosis and the US-guided biopsy. These results show significant differences in the accuracy of US-guided biopsy. In the case of soft tissue sarcomas, 6 out of 12 cases, in which only MR perfusion had been conducted, matched the result of the definitive diagnosis and the US-guided biopsy. 17 out of 18 cases, in which both PET-CT and MR perfusion were conducted, matched the definitive diagnosis. Moreover US-guided biopsy also showed significant differences in the accuracy of US-guided biopsy. Conclusion: In diagnosing soft tissue tumors, a US-guided biopsy is a well-known tool for its high accuracy. However, the heterogeneity of sarcoma makes it difficult to locate the exact site for a biopsy using only MR perfusion. Thus, the use of PET-CT will meaningfully improve the accuracy of a diagnosis by precisely targeting the site for the US-guided biopsy.

• Journal of the Korean Orthopaedic Association
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• v.56 no.3
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• pp.224-233
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• 2021

Purpose: The purpose of this study was to retrospectively evaluate the effect of 'Blocking Kirschner Wire (K-Wire) Technique', which has been developed to reduce protrusion of the lateral wall, in maintaining the level of reduction through clinical and radiological outcomes. Materials and Methods: Twenty-two patients with displaced intra-articular calcaneal fractures who used the blocking K-wire to maintain reduction (group A) and 44 patients that did not use blocking K-wire and were paired in 1:2 ratio with those Group A patients (group B), between January 2015 and December 2017 were enrolled in the study. All surgical procedures were performed via the extended sinus tarsi approach, and internal fixation using cannulated screws, Steinmann pins and K-wires was performed. American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot scale and postoperative recovery of exercise ability were compared for postoperative clinical outcomes. The radiological results were compared the Böhler angle, Gissane angle, calcaneal height and width, step off of posterior calcaneal joint, and the degree of protrusion of the lateral wall. Moreover, postoperative complications in both groups were compared. Results: There were no significant differences in the clinical outcomes of the two groups (p=0.924, p=0.961). The amount of Böhler angle, Gissane angle, calcaneal height and width, and step off of posterior calcaneal joint from the radiological results was not significantly different between the two groups (p=0.170, p=0.441, p=0.230, p=0.266, and p=0.400). However, the degree of protrusion of the lateral wall was 1.78 mm and 4.95 mm in group A and group B, respectively, and the difference between the two groups was significant (p=0.017). Although sural nerve entrapment and painful exostosis were more frequent in group B, they were occurred in a non-significant manner (p=0.293, p=0.655). Conclusion: Most of the clinical and radiological results as well as the complications were not significantly different between the two groups. However, the degree of protrusion of the calcaneus lateral wall in group A was promising. The 'Blocking K-Wires Technique' established by the authors may be an effective surgical option for maintaining the reduction of the lateral wall protrusion in displaced intraarticular calcaneal fractures.

• The Korean Journal of Nuclear Medicine Technology
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• v.26 no.1
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• pp.38-41
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• 2022

Purpose Testosterone is a steroid hormone synthesized by the Leydig cells of the testes in men, and by the adrenal cortex and ovaries in women. Testosterone production is regulated by luteinzing hormone secreted by the anterior pituitary gland. In this experiment, the effectiveness of testosterone radioimmunoassay (RIA) kits produced by three companies was evaluated and compared in case the production of testosterone kits was stopped or supply problems occurred. Materials and Methods In October 2021, samples were collected from the patients (n=49) who requested the testosterone RIA test. The experiment was conducted by dividing the patient's sample into low concentration (1.0 ng/mL or less), medium concentration (2.0-4.0 ng/mL) and high concentration (6.0 ng/mL or more). The Testosterone RIA test compared and evaluated the validity of Company A kits used in this hospital and those of Company B and C used in other hospitals. The precision, sensitivity, recovery, linearity and correlation were evaluated for each kit. The testosterone RIA test was carried out in accordance with the insert kit manual for each manufacturer. Results As a result of measuring the precision of the intra assay, the Coefficient of Variation (CV) value of the company A kit was high at 11.4% only in the low concentration sample, and in the case of the company B and C kits, the CV value was less than 10% at low, medium, and high concentrations. In the inter-assay precision measurement, the CV value was less than 15% in both A and C kits, but in the case of the B kit, the CV value exceeded 15% at low and medium concentrations. Sensitivity was 0.13 ng/mL for company A, 0.01 ng/mL for company B, and 0.01 ng/mL for company C, and the linearity of all three kits showed excellent linearity. In the case of recovery rate, all of the A, B, and C company kits showed results that were out of 90-110%. In the case of correlation test, when compared with the company A kit currently use in here, the correlation coefficient (R²) value for the company B kit was 0.9508, and for the company C kit was 0.9352 Conclusion As a result, there was a slight difference in precision at the low concentration sample. The correlation test showed an excellent correlation coefficient. However, it was difficult to secure samples of various concentrations because there were not many tests of testosterone requested at this hospital. So, additional experiments should be carried out by acquiring samples of various concentrations on each laboratory later.