• Transactions of the Korean hydrogen and new energy society
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• v.34 no.5
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• pp.447-455
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• 2023

SAE J2601, hydrogen fueling protocols, proposes two charging methods. The first is the table-based fueling protocol, and the second is the MC formula-based fueling protocol. Among them, MC formula-based fueling protocol calculates and supplies the target pressure and pressure ramp rate (PRR) using the pre-cooling temperature of the hydrogen and the physical parameters of the tank in the vehicle. The coefficient of the MC formula for deriving MC varies depending on the physical parameters of the tank in the vehicle. However, most studies use the MC coefficient derived from SAE J2601 as it is, despite the difference in the physical parameters of the tank applied to the study and the tank used to derive the MC coefficient from SAE J2601. In this study, the MC coefficient was derived by applying the hydrogen tank currently used, and the difference with the fueling performance using the MC coefficient proposed in SAE J2601 was verified. In addition, the difference was confirmed by comparing and analyzing the fueling performance of the table-based method currently used in hydrogen fueling stations and the MC formula-based method using MC coefficient derived in this study.

• The Journal of Korean Academy of Prosthodontics
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• v.61 no.4
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• pp.268-274
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• 2023

In this case, a CAD-CAM complete denture that can be easily remanufactured and reduced the number of visits was decided in consideration of the fact that it was difficult to visit the dental hospital and many existing dentures were lost because the patient was inpatient in a nursing hospital. In order to reflect the shape, vertical dimension, and maxillomandibular relationship of the existing provisional dentures adapted by the patient to the fabrication of the final denture, the existing provisional dentures were scanned and closed mouth impression was taken with the printed individual tray. After digital facebow transfer using UTS CAD and arranging artificial teeth in CAD software, the maxillary and mandibular complete dentures were fabricated by milling the denture base and artificial teeth at once with the monolithic disc.

• Journal of Internet of Things and Convergence
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• v.9 no.6
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• pp.1-9
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• 2023

Malware files containing concealed malicious scripts have recently been identified within MS Office documents frequently. In response, this paper describes the design and implementation of a system that automatically detects malicious digital files using machine learning techniques. The system is proficient in identifying malicious scripts within MS Office files that exploit the OLE VBA macro functionality, detecting malicious scripts embedded within the CDH/LFH/ECDR internal field values through OOXML structure analysis, and recognizing abnormal CDH/LFH information introduced within the OOXML structure, which is not conventionally referenced. Furthermore, this paper presents a mechanism for utilizing the VirusTotal malicious script detection feature to autonomously determine instances of malicious tampering within MS Office files. This leads to the design and implementation of a machine learning-based integrated software. Experimental results confirm the software's capacity to autonomously assess MS Office file's integrity and provide enhanced detection performance for arbitrary MS Office files when employing the optimal machine learning model.

• Applied Chemistry for Engineering
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• v.34 no.5
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• pp.479-487
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• 2023

Copper is cost-effective and abundantly available as a biocidal coating agent for a wide range of material surfaces. Natural oxidation does not compromise the efficacy of copper, allowing it to maintain antimicrobial activity under prolonged exposure conditions. Furthermore, copper compounds exhibit a broad spectrum of antimicrobial activity against pathogenic yeast, both enveloped and non-enveloped types of viruses, as well as gram-negative and gram-positive bacteria. Contact killing of copper-coated surfaces causes the denaturation of proteins and damage to the cell membrane, leading to the release of essential components such as nucleotides and cytoplasm. Additionally, redox-active copper generates reactive oxygen species (ROS), which cause permanent cell damage through enzyme deactivation and DNA destruction. Owing to its robust stability, copper has been utilized in diverse forms, such as nanoparticles, ions, composites, and alloys, resulting in the creation of various coating methods. This mini-review describes representative coating processes involving copper ions and copper oxides on various material surfaces, highlighting the antibacterial and antiviral properties associated with different oxidation states of copper.

• Journal of Dental Rehabilitation and Applied Science
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• v.39 no.3
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• pp.168-175
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• 2023

Long-term use of inappropriate prosthesis often results in habitual closure or irregular mandibular movements. In that case, guide to the stable centric position is difficult. Therefore, by using a treatment denture, the muscles and TMJ should be stabilized and the jaw relation should be acquired with the treatment position. Compared to the conventional method, digital technology in fabrication complete denture has the advantage of reproducing a stable tooth arrangement in cases of difficult tooth alignment, minimizing laboratory errors and reducing denture fabrication time. Therefore, in this case, the final denture was fabricated by digitally reproducing the stable treatment position, vertical dimension, and lip support with a treatment denture, and satisfactory results were obtained.

• International conference on construction engineering and project management
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• 2011.02a
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• pp.66-73
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• 2011

With rapid industrialization, electric power consumption has been increasing every year in Korea and in other countries. The provision of additional power stations to produce more electricity is one possible response to this steady increase in consumption. Another alternative is to improve the efficiency of existing stations through timely and effective maintenance works. Since the construction of a new power plant involves a large amount of capital as well as difficulties in the selection of sites, the improvement of existing power stations' efficiencies is often a preferred solution. Therefore, this paper focuses on maintenance project management to address this issue. Among several types of maintenance works, this paper concentrates on planned outage maintenance (POM). This focus arises from the critical impact of POM on other maintenance work, as well as the entire process of electricity production. Unlike other maintenance work, POM is done on the basis of mid and long-term plans. In addition, only POM works are conducted during the outage of all power plants. To evaluate the efficiency of POM works, budget data relating to 164 POM projects between 2001 and 2008 was collected from 7 sites in South Korea. Data envelopment analysis (DEA) was selected as a methodology for evaluation. From this analysis, comparative study was used to determine the categories of projects that had performed well, and those with the most optimized budget structures. Moreover, through discussion with industry, this research develops a feasible proposed method by which to enhance the efficiency of POM projects.

• International conference on construction engineering and project management
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• 2011.02a
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• pp.187-194
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• 2011

Optimizing truck dispatching-intervals is imperative in ready mixed concrete (RMC) delivery process. Intervals shorter than optimal may induce queuing of idle trucks at a construction site, resulting in a long delivery cycle time. On the other hand, intervals longer than optimal can trigger work discontinuity due to a lack of available trucks where required. Therefore, the RMC delivery process should be systematically scheduled in order to minimize the occurrence of waiting trucks as well as guarantee work continuity. However, it is challenging to find optimal intervals, particularly in urban areas, due to variations in both traffic conditions and concrete placement rates at the site. Truck dispatching intervals are usually determined based on the concrete plant managers' intuitive judgments, without sufficient and reliable information regarding traffic and site conditions. Accordingly, the RMC delivery process often experiences inefficiency and/or work discontinuity. Automatic data collection (ADC) techniques (e.g., RFID or GPS) can be effective tools to assist plant managers in finding optimal dispatching intervals, thereby enhancing delivery performance. However, quantitative evidence of the extent of performance improvement has rarely been reported to data, and this is a central reason for a general reluctance within the industry to embrace these techniques, despite their potential benefits. To address this issue, this research reports on the development of a discrete event simulation model and its application to a large-scale building project in Abu Dhabi. The simulation results indicate that ADC techniques can reduce the truck idle time at site by 57% and also enhance the pouring continuity in the RMC delivery process.

• International journal of advanced smart convergence
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• v.12 no.4
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• pp.208-216
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• 2023

The purpose of our study is to design datasets for Artificial Intelligence learning for cold sea fish farming. Salmon is considered one of the most popular fish species among men and women of all ages, but most supplies depend on imports. Recently, salmon farming, which is rapidly emerging as a specialized industry in Gangwon-do, has attracted attention. Therefore, in order to successfully develop salmon farming, the need to systematically build data related to salmon and salmon farming and use it to develop aquaculture techniques is raised. Meanwhile, the catch of pollack continues to decrease. Efforts should be made to improve the major factors affecting pollack survival based on data, as well as increasing the discharge volume for resource recovery. To this end, it is necessary to systematically collect and analyze data related to pollack catch and ecology to prepare a sustainable resource management strategy. Image data was obtained using CCTV and underwater cameras to establish an intelligent aquaculture strategy for salmon and pollock, which are considered representative fish species in Gangwon-do. Using these data, we built learning data suitable for AI analysis and prediction. Such data construction can be used to develop models for predicting the growth of salmon and pollack, and to develop algorithms for AI services that can predict water temperature, one of the key variables that determine the survival rate of pollack. This in turn will enable intelligent aquaculture and resource management taking into account the ecological characteristics of fish species. These studies look forward to achievements on an important level for sustainable fisheries and fisheries resource management.

• Journal of Navigation and Port Research
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• v.47 no.6
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• pp.324-330
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• 2023

Aids to navigation, which provide information about a ship's position, direction, and the location of obstacles, are crucial for uninterrupted maritime services. This study aimed to analyze accidents involving aids to navigation that resulted in service disruptions and identify the key factors associated with these accidents. Aids to navigation accident data from 2000 to 2022 were utilized to achieve this. We categorized accidents by accident type, cause, region, season, and type of navigation aid and established a network through correlation analysis. Bayesian networks based on aids to navigation accidents were assigned prior probabilities, and the factors that increased the probability of accidents for different types of aids to navigation were identified. The findings can be used to infer the causes of unreported aids to navigation accidents and serve as foundational data for the prevention of such accidents.

• Korean Journal of Radiology
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• v.21 no.6
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• pp.684-694
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• 2020

Objective: The purpose was to review the diagnostic performance of the length of tumor capsular contact (LCC) on magnetic resonance imaging (MRI) for detecting prostate cancer extraprostatic extension (EPE). Materials and Methods: PubMed and EMBASE databases were searched up to March 24, 2019. We included diagnostic accuracy studies that evaluated LCC on MRI for EPE detection using radical prostatectomy specimen histopathology as the reference standard. Quality of studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool. Sensitivity and specificity were pooled and graphically presented using hierarchical summary receiver operating characteristic (HSROC) plots. Meta-regression and subgroup analyses were conducted to explore heterogeneity. Results: Thirteen articles with 2136 patients were included. Study quality was generally good. Summary sensitivity and specificity were 0.79 (95% confidence interval [CI] 0.73-0.83) and 0.67 (95% CI 0.60-0.74), respectively. Area under the HSROC was 0.81 (95% CI 0.77-0.84). Substantial heterogeneity was present among the included studies according to Cochran's Q-test (p < 0.01) and Higgins I² (62% and 86% for sensitivity and specificity, respectively). In terms of heterogeneity, measurement method (curvilinear vs. linear), prevalence of Gleason score ≥ 7, MRI readers' experience, and endorectal coils were significant factors (p ≤ 0.01), whereas method to determine the LCC threshold, cutoff value, magnet strength, and publication year were not (p = 0.14-0.93). Diagnostic test accuracy estimates were comparable across all assessed MRI sequences. Conclusion: Greater LCC on MRI is associated with a higher probability of prostate cancer EPE. Due to heterogeneity among the studies, further investigation is needed to establish the optimal cutoff value for each clinical setting.