• Journal of Radiation Protection and Research
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• v.48 no.4
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• pp.197-203
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• 2023

Background: The thermoluminescent dosimeter (TLD) and Monte Carlo (MC) dosimetry are carried out to determine the occupational dose for personnel in the handling of ¹²⁵I seed sources. Materials and Methods: TLDs were placed in different layers of the Alderson-Rando phantom in the thyroid, lung and also eyes and skin surface. An ¹²⁵I seed source was prepared and its activity was measured using a dose calibrator and was placed at two distances of 20 and 50 cm from the Alderson-Rando phantom. In addition, the Monte Carlo N-Particle Extended (MCNPX 2.6.0) code and a computational phantom with a lattice-based geometry were used for organ dose calculations. Results and Discussion: The comparison of TLD and MC results in the thyroid and lung is consistent. Although the relative difference of MC dosimetry to TLD for the eyes was between 4% and 13% and for the skin between 19% and 23%, because of the existence of a higher uncertainty regarding TLD positioning in the eye and skin, these inaccuracies can also be acceptable. The isodose distribution was calculated in the cross-section of the head phantom when the ¹²⁵I seed was at two distances of 20 and 50 cm and it showed that the greatest dose reduction was observed for the eyes, skin, thyroid, and lungs, respectively. The results of MC dosimetry indicated that for near the head positions (distance of 20 cm) the absorbed dose rates for the eye lens, eye and skin were 78.1±2.3, 59.0±1.8, and 10.7±0.7 µGy/mCi/hr, respectively. Furthermore, we found that a 30 cm displacement for the ¹²⁵I seed reduced the eye and skin doses by at least 3- and 2-fold, respectively. Conclusion: Using a computational phantom to monitor the dose to the sensitive organs (eye and skin) for personnel involved in the handling of ¹²⁵I seed sources can be an accurate and inexpensive method.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.7
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• pp.819-827
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• 2023

If respiratory arrest occurs or cardiopulmonary resuscitation (CPR) is performed for a long period on board ships, CPR with rescue breathing (not compression-only CPR) is required. Accordingly, ships must have resuscitation equipment for oxygen supply, and seafarers must have the maritime competence to use it. This study aimed to analyze the placement status of resuscitation equipment on ships and seafarers' intention to use them in order to increase the usability of resuscitation equipment on board ships and propose improvement measures. The study was conducted from February 2, 2023, to April 21, 2023, and a total of 340 seafarers were surveyed. The data were analyzed by frequency, percentage, and chi-square test using SPSS WIN 23.0. The results showed that the checking of resuscitation equipment was high among seafarers in the positions of officer, captain, deck department personnel, and ocean-going personnel. The intention of seafarers to use resuscitation equipment was low, and the main barrier was the lack of knowledge on how to use. Among the general characteristics of the study participants, those whose rank was that of officer or captain, whose working department was the deck, voyage who were ocean-going, and who managed a gross tonnage of 20,000 tons or more had a high intention to use resuscitation equipment. Participants who knew the necessity of rescue breathing and had received practice and equipment-based training were active in using resuscitation equipment. Therefore, a system should be developed so that all ships can be equipped with resuscitation equipment, and an environment must be created to increase accessibility to resuscitation equipment on board ships. In addition, an education system based on practical and resuscitation equipment training must be established to ensure that seafarers have maritime competence.

• Journal of the Korean Society of Radiology
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• v.17 no.7
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• pp.1099-1108
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• 2023

The mortise view radiography procedure is an ankle joint examination and observes the presence of trauma, sprain, or dislocation suspected in the ankle joint. The auxiliary equipment used during the mortise view radiography procedure can generate artifacts in the radiograph images and is not diverse enough to be custom-made for each patient; not cost-efficient. The purpose of this study is to create a custom assistive device to support mortise view radiography procedure. This study utilized 3D printing technology to create the mortise view radiography procedure assistive device (ShinHan Device; SHD). The lengths of the tibiotalar joint (TTJ), talar calcaneal joint (TCJ), and medial joint (MJ) were measured and evaluated by five researchers using both SHD and the prototype Hologic tool. The mean ranges were found to be 39.42-39.47 mm for TTJ, 31.41-31.57 mm for TCJ, and 21.21-21.23 mm for MJ while using SHD device. On the other hand, the measurements showed mean ranges of 39.73-39.79 mm for TTJ, 31.46-31.50 mm for TCJ, and 21.31-21.35 mm for MJ while using the Hologic tool. Based on this study results, the error ranges at all positions decreased by 24% for TTJ, 17% for TCJ, and 36% for MJ when using SHD device compared to the Hologic tool. Moreover, when SHD was used, it allowed for a highly reproducible examination posture (ICC = 0.99), and it enabled the acquisition of radiograph images without artifacts, which were present in the Hologic tool.

• Korean Journal of Ecology and Environment
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• v.56 no.3
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• pp.218-228
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• 2023

Invasive predators are one of the most damaging species groups to biodiversity. In the Nakdong River, the lake skygazer Chanodichthys erythropterus is a dominant species that is fiercely carnivorous and a concern for commercial fish. Although it is important to understand the ecological characteristics related to the feeding habit, studies on the diets of lake skygazer in Nakdong River have been limited to studies of gut contents. In this study, the trophic position (TP) and feeding habits of C. erythropterus were studied by calculating TPs using samples collected from 13 sites throughout the Nakdong River. Compound-specific isotopic analysis of amino acids provided reliable TPs from the muscle of Lake skygazer C. erythropterus without any isotope baseline. The results were approximately 3 to 3.6 and suggesting a carnivorous but size-dependent prey variation. In particular, the TP variability of C. erythropterus observed in the Nakdong River showed that it had a selective feeding habit compared to carnivorous fish species of relatively similar trophic levels.

• Korean Journal of Mineralogy and Petrology
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• v.36 no.4
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• pp.259-271
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• 2023

Since the short-wave infrared spectrum has a significant range of variation depending on the production environment, countries with advanced resource exploration are collecting the spectrum and building a database. Representative organizations include the USGS and CSIRO, and they are currently carrying out a project in China that can synthesize and use a large number of existing data. The USGS library provides a total of 2,457 spectra targeting not only minerals but also various materials that respond to infrared radiation. Among these, there are 1,276 mineral spectra, which are about half of the total. The spectrum title includes information, such as analysis devices (NIC4, BECK, ASDNG, etc.), purity codes (a, b, c, d, u), and measurement methods (AREF, RREF, RTGC, TRAN). Analyzed raw data are provided in ASCII and GIF format. The CSIRO library has a total of 502 spectra, of which the majority, 493, correspond to mineral spectra. The USGS library is a free, publically available resource, while the CSIRO library is bundled with TSG8 or must be purchased separately. Among these, when comparing the eight spectra whose spectral shapes can be analyzed with the spectra of domestic illite, the positions of the absorption peaks are significantly different from those of domestic illite, except for one Japanese illite. Additional research will be needed to determine the causes of such differences, and the domestically relevant databases should be established as well.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.16 no.6
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• pp.519-525
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• 2023

The human brain constantly emits electrical impulses, which is called brain waves, and brain waves can be defined as the electrical activity of the brain generated by the flow of ions generated by the biochemical interaction of brain cells. There is a study that emotion is one of the factors that can cause stress. Brain waves are the most used in the study of emotions. This paper is a study on whether emotions affect stress, and showed two images of fear and joy to four experimenters and divided them into three stages before, during, and after watching. As a measurement tool, brain waves at the positions of Fp1 and Fp2 were measured using the NeuroBrain System, a system that can automate brain wave measurement, analysis, brain wave reinforcement, and suppression training with remote control. After obtaining the brain wave data for each emotion, the average value was calculated and the study was conducted. As for the frequency related to stress, the values of Alpha and SMR, Low Beta, and High Beta were analyzed. Brainwave analysis affects stress depending on the emotional state, and "fear" emotions cause anxiety by raising Beta levels, resulting in higher Mind Stress levels, while "joy" emotions lower Beta levels, resulting in a significant drop in Mind Stress.

• Journal of Aerospace System Engineering
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• v.18 no.1
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• pp.37-45
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• 2024

This paper presents a design approach for passive vibration control to reduce vertical vibrations transmitted to the control unit during hovering flight of a quadrotor drone. Ground vibration test simulation based on finite element model was performed for forced vibration analysis of the quadrotor drone. First, modal analysis was performed to evaluate dynamic characteristics. Forced vibration response analysis was then performed to obtain the steady-state response within the operating frequency range under the hovering flight condition. Furthermore, to obtain the vibration reduction effect, a viscous damping tape was applied at positions that could induce vibrations transmitted to the control unit under the same conditions. Such a passive vibration control approach was investigated. Relevant vibration reduction effect was assessed with respect to the application of damping materials and the attachment position.

• Korean Association of Arts Management
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• no.50
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• pp.177-212
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• 2019

In an effort to understand the global standing of artists from Japan, China, and Korea, this article presents an analytic study of data from auctions, notable international contemporary art galleries, notable international art museums, contemporary art biennials, and the Venice Biennales' award. We also look at select art exhibitions as they have been covered by international art magazines to analyze the geography of international contemporary art. Our analysis of international art magazines shows that the global position of the three Asian countries we consider is low in comparison with select Western countries. Auction data, on the other hand, reveals that Chinese and Japanese artists are highly regarded in economic terms, while the visibility of Japanese artists is emphasized in the data we consider from art biennials. In the permanent exhibitions and contemporary art biennales we look at, we note that the visibility of Chinese artists is much higher than that of Japanese and Korean artists, who also demonstrate remarkable visibility. We find that Korean artists represent an important presence in our analysis of the Venice Biennale awards, with Japanese and Chinese artists holding noteworthy positions. Through these myriad criteria, we develop a clear idea of the nature of the global position of artists from Japan, China, and Korea. The Asian art world can profit from these findings by considering them when developing strategies for managing the growth of its artists on the international contemporary art scene.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.12 no.3
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• pp.219-224
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• 2007

Two monitoring buoys equipped with ADCP were deployed at the deepest positions along the trough of the central Gwangyang Bay in spring 2006 in order to study the circulation in the bay. Northward velocity is commonly dominant at both stations located in the eastern part of the channel, which supports the cyclonic circulation accompanied by the southward flow in the western part. The southern station has a distinct two-layer structure with current reversal at 14 m depth and increasing northward velocity in the lower layer to 36 m depth close to the bottom. At the northern station the northward flow becomes accelerated due to the decrease in the cross-sectional area and this northward current is dominant even in the upper layer. In the modal structure from the EOF analysis, the first mode has 74% of total variance at the northern station whereas it is 67% but the baroclinic portion increases at the southern station. The typical northward velocity is about 10 cm/s which is associated with the cyclonic circulation. Subtidal variability due to the local wind effect is negligible, but the nonlocal response associated with offshore Ekman flux by the zonal wind is found during strong wind events.

• Journal of the Korea Institute of Building Construction
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• v.24 no.2
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• pp.239-248
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• 2024

The adjustment in guidelines for quality certification of recycled aggregate permitted the Quality Control Manager of a company specializing in recycled aggregate quality certification to concurrently assume the role of Environmental Management Manager. Analysis of the outcomes from the 2023 recycled aggregate quality certification follow-up management audit conducted by the certification agency revealed that in 95 out of 242 cases, constituting approximately 39% of the total cases, individuals held concurrent positions. Following the regulatory revision, there has been a notable proliferation of concurrent roles across various enterprises. Concerns arose regarding the potential neglect of quality control for certified recycled aggregates in comparison to scenarios where individuals are solely responsible for specific duties related to quality and environmental management. Audit results encompassing six aspects, including waste management, were evaluated on a scale of 6 points. A comparative analysis was conducted between the outcomes of 147 cases managed by dedicated personnel, as previously practiced, and 95 cases managed by individuals with concurrent roles. Although the average score of the latter group was marginally lower, no statistically significant disparity was observed between the two groups. Consequently, apprehensions regarding the oversight of quality control stemming from the allowance of concurrent roles appear unfounded. Within the context of recent regulatory revisions, permitting concurrent roles in managerial capacities is deemed an appropriate relaxation of regulations.