• Korean Journal of Heritage: History & Science
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• v.57 no.1
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• pp.6-19
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• 2024

The Korean Archaeological Dictionary, which represents Korean archaeological knowledge information, contains refined and high-quality information written by expert collective intelligence. This is a characteristic that clearly distinguishes it from overseas archaeological data archives, and can be called differentiated infrastructure data. However, it has not played a role as an information service or knowledge information platform reflecting the latest digital technology. As a way to maximize these strengths and compensate for weaknesses, it was proposed to develop and operate a GIS-based knowledge and information platform for Korean archaeology. To realize this, it is necessary to develop a title management system centered on repositories and metadata that can collect and store various information, link open linked data design and related systems, develop a search function that can analyze and visualize data in response to the big data era, and establish a WebGIS-based information service system. This will be a platform to continuously manage, supplement, and update Korean archaeological knowledge information, build a ubiquitous environment where anyone can use information anytime, anywhere, and create various types of business models.

• Clinical Endoscopy
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• v.57 no.4
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• pp.476-485
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• 2024

Background/Aims: Sedation has become a standard practice for patients undergoing gastrointestinal (GI) endoscopy. However, considering the serious cardiopulmonary adverse events associated with sedatives, it is important to identify patients at high risk. Machine learning can generate reasonable prediction for a wide range of medical conditions. This study aimed to evaluate the risk factors associated with sedation during GI endoscopy and develop a predictive model for hypoxia during endoscopy under sedation. Methods: This prospective observational study enrolled 446 patients who underwent sedative endoscopy at the Korea University Ansan Hospital. Clinical data were used as predictor variables to construct predictive models using the random forest method that is a machine learning algorithm. Results: Seventy-two of the 446 patients (16.1%) experienced life-threatening hypoxia requiring immediate medical intervention. Patients who developed hypoxia had higher body weight, body mass index (BMI), neck circumference, and Mallampati scores. Propofol alone and higher initial and total dose of propofol were significantly associated with hypoxia during sedative endoscopy. Among these variables, high BMI, neck circumference, and Mallampati score were independent risk factors for hypoxia. The area under the receiver operating characteristic curve for the random forest-based predictive model for hypoxia during sedative endoscopy was 0.82 (95% confidence interval, 0.79-0.86) and displayed a moderate discriminatory power. Conclusions: High BMI, neck circumference, and Mallampati score were independently associated with hypoxia during sedative endoscopy. We constructed a model with acceptable performance for predicting hypoxia during sedative endoscopy.

• Journal of Aerospace System Engineering
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• v.18 no.4
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• pp.10-17
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• 2024

Solar-powered unmanned aerial vehicles(SPUAV), which are being actively developed domestically and internationally, generally feature high aspect ratio(AR) wings. These high AR wings necessitate a lightweight design as their weight increases, rendering them susceptible to flutter. Consequently, flutter analysis is critical from the initial design phase. Typically, flutter analysis is conducted using a standard section wing or more precisely through a 3D model. However, due to the extended analysis time required by 3D models, this study opts for a 2D aircraft model. The 2D model computes faster than the 3D model and intuitively secures the flutter boundary. In this study, a structural/aerodynamic force model of the 2D aircraft was established, and the findings were compared with those from a 3D half model. The results showed that the flutter analysis between the 2D model and the 3D half model was similar, within about a 3% margin, thus validating the proposed 2D model's effectiveness.

• Journal of Korean Society of Water and Wastewater
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• v.38 no.4
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• pp.199-208
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• 2024

In this paper, the adsorption removal characteristic for 10 species of perfluoroalkyl and polyfluoroalkyl substances (PFAS) was investigated using GAC and modified GAC (GAC-Cu). After modification with Cu(II), the amount of copper was to 1.93 and 4.73 mg/g for GAC and GAC-Cu, respectively. The total amount of 10 species of PFAS per specific area was obtained to 0.548 and 0.612 ng/m² for GAC and GAC-Cu, respectively. A series of batch test confirmed lower efficiency was observed with a smaller number of carbon chain length and the removal efficiency of PFCA (perfluoroalkyl carboxylic acids) was lower than that of PFSA (perfluoroalkyl sulfonic acids) with the same carbon chain length. Regarding the pH effect, the adsorption capacity was decreased with increase of pH due to the increase of electrostatic repulsion. According to pseudo first and second order (PFO and PSO) kinetic models, while the values of equilibrium uptake and time did not show significant difference, a difference in uptake was observed between 24-48h. Furthermore, based on correlation analysis, Log K_ow and uptake have a high correlation with molecular weight (M.W.) and initial concentration, respectively. These results show that long-chain PFAS have higher removal efficiency due to their increased hydrophobicity.

• Geophysics and Geophysical Exploration
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• v.11 no.1
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• pp.1-14
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• 2008

We present a method for interpreting seismic records with arrivals and waveforms having characteristics which could be generated by extremely inhomogeneous velocity structures, such as non-typical oceanic crust, decollement at subduction zones, and seamounts in oceanic regions, by comparing them with synthetic waveforms. Recent extensive refraction and wide-angle reflection surveys in oceanic regions have provided us with a huge number of high-resolution and high-quality seismic records containing characteristic arrivals and waveforms, besides first arrivals and major reflected phases such as PmP. Some characteristic waveforms, with significant later reflected phases or anomalous amplitude decay with offset distance, are difficult to interpret using only a conventional interpretation method such as the traveltime tomographic inversion method. We find the best process for investigating such characteristic phases is to use an interactive interpretation method to compare observed data with synthetic waveforms, and calculate raypaths and traveltimes. This approach enables us to construct a reasonable structural model that includes all of the major characteristics of the observed waveforms. We present results here with some actual observed examples that might be of great help in the interpretation of such problematic phases. Our approach to the analysis of waveform characteristics is endorsed as an innovative method for constructing high-resolution and high-quality crustal structure models, not only in oceanic regions, but also in the continental regions.

• Journal of the Korean Society of Radiology
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• v.18 no.3
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• pp.187-201
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• 2024

Osteoporosis is a major health issue globally, often remaining undetected until a fracture occurs. To facilitate early detection, deep learning (DL) models were developed to classify osteoporosis using abdominal computed tomography (CT) scans. This study was conducted using retrospectively collected data from 3,012 contrast-enhanced abdominal CT scans. The DL models developed in this study were constructed for using image data, demographic/clinical information, and multi-modality data, respectively. Patients were categorized into the normal, osteopenia, and osteoporosis groups based on their T-scores, obtained from dual-energy X-ray absorptiometry, into normal, osteopenia, and osteoporosis groups. The models showed high accuracy and effectiveness, with the combined data model performing the best, achieving an area under the receiver operating characteristic curve of 0.94 and an accuracy of 0.80. The image-based model also performed well, while the demographic data model had lower accuracy and effectiveness. In addition, the DL model was interpreted by gradient-weighted class activation mapping (Grad-CAM) to highlight clinically relevant features in the images, revealing the femoral neck as a common site for fractures. The study shows that DL can accurately identify osteoporosis stages from clinical data, indicating the potential of abdominal CT scans in early osteoporosis detection and reducing fracture risks with prompt treatment.

• 한국균학회소식:학술대회논문집
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• 2015.05a
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• pp.15-15
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• 2015

Aspergillus fumigatus is a major cause of invasive aspergillosis (IA), a significant health issue worldwide with high mortality rates up to 95%. Our lab is interested in how A. fumigatus adapts to low oxygen conditions 'hypoxia', which is one of the important host microenvironments. A. fumigatus SrbA is a basic helix-loop-helix (bHLH) transcriptional regulator and belongs to sterol regulatory element binding protein (SREBP) family members. Loss of SrbA completely blocks growth in hypoxia and results in avirulence in murine models of IA suggesting an essential role of SrbA in hypoxia adaptation and virulence in A. fumigatus. We conducted chromatin immunoprecipitation sequencing (ChIP-seq) with A. fumigatus wild type using a SrbA specific antibody, and 97 genes were revealed as SrbA direct targets. One of the 'SrbA regulons' (AFUB_099590) was a putative bHLH transcriptional regulator whose sequence contained a characteristic tyrosine substitution in the basic portion of the bHLH domain of SREBPs. Therefore, we designated AFUB_099590 SrbB. Further characterization of SrbB demonstrated that SrbB is important for radial growth, biomass production, and biosynthesis of heme intermediates in hypoxia and virulence in A. fumigatus. A series of quantitative real time PCR showed that transcription of several SrbA regulons is coordinately regulated by two SREBPs, SrbA and SrbB in hypoxia. This suggests that SrbA and SrbB have both dependent and independent functions in regulation of genes responsible for hypoxia adaptation in A. fumigatus. Together, our data provide new insights into complicated roles of SREBPs in adaptation of host environments and virulence in pathogenic fungi.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.2
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• pp.597-604
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• 2014

In this study, we investigate to show the limitations of current bus arrival time estimation model based on each bus route, and to propose a bus arrival time estimation model based on a bus stop to overcome these limitations. Using the characteristic of bus arrival time calculated on travel time between two bus stops, we develop a model to estimate bus arrival times with the data of all buses traveling the same section regardless of bus route numbers. In the proposed model, an estimated arrival time is calculated by weighted moving average method, and verification between observed value and estimated time is performed on the basis of RMSE. Error was reduced by up to 20% compared to the existing models and the data update period was reduced by more than half that is related to the accuracy of bus arrival time information. We expect to solve the following problems with the suggested method: sudden increase or decrease in arrival time of the bus, the difference of the expected arrival times at the same stop between two or more buses having different route numbers, and impossibility of offering information of a bus if the bus is not operated with the designated schedule.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.9
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• pp.4745-4749
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• 2012

The diagnosis of malignant mesothelioma (MM) remains a clinical challenge and the fluorescence in situ hybridization (FISH) assay has been reported to be one promising tool. The present meta-analysis aimed to establish the overall diagnostic accuracy of FISH for diagnosing MM. After a systematic review of English language studies, the sensitivity, specificity and other measures of accuracy of FISH in the diagnosis of MM were pooled using random-effects models. Summary receiver operating characteristic curves were applied to summarize overall test performance. Nine studies met our inclusion criteria, the pooled sensitivity and specificity for FISH for diagnosing MM being 0.72 (95% CI 0.67-0.76) and 1.00 (95% CI 0.98-1.00), respectively. The positive likelihood ratio was 34.5 (95% CI 14.5-82.10), the negative likelihood ratio was 0.24 (95% CI 0.16-0.36), and the diagnostic odds ratio was 204.9 (95% CI 76.8-546.6), the area under the curve being 0.99. Our data suggest that the FISH assay is likely to be a useful diagnostic tool for confirming MM. However, considering the limited studies and patients included, further large scale studies are needed to confirm these findings.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.7
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• pp.58-65
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• 2019

Polymer concrete is expected to be widely used as a building material because it has a shorter hardening time and excellent compression, tensile, bending, bond strength, frictional resistance and abrasion loss compared to general concrete. The polymer concrete has excellent vibration damping performance and research on the use of various reinforcing materials is being conducted. However, in order to completely replace the general concrete and the general anti-vibration reinforcement, such polymer concrete requires an overall review of vibration reduction performance considering physical properties, dynamic properties, productivity and field applicability. In this study, the physical and dynamic properties of polymer concrete by epoxy mixing ratio were compared with those of general concrete. It was appeared that compression, tensile, bending and bond strengths of polymer concrete by epoxy mixing were significantly higher than those of general concrete. Especially, the tensile strength was more than 4 ~ 6.5 times. Based on the basic physical properties of polymer concrete, the damping ratio, which is a dynamic characteristic according to the epoxy mixing ratio, was derived through analytical models and experiments. As a result, the dynamic stiffness of polymer concrete was 20% higher than that of general concrete and the loss rate was about 3 times higher.