• Journal of the Korean Society of Radiology
• /
• v.16 no.3
• /
• pp.257-263
• /
• 2022

In intracavitary radiotherapy, it is essential to verify the correct location of radiation source among quality control items because an incorrect location will irradiate an unnecessary dose to normal tissues. As a basic study of digital line dosimeters, this study fabricated a unit cell dosimeter based on polycrystalline mercury (II) iodide (HgI₂) and compared its performance with a diode. The study result showed that for reproducibility, the relative standard deviation (RSD) was 1.21%, satisfying the RSD evaluation criterion of within 1.5%. Considering linearity, the coefficient of determination R² showed an excellent result of 0.9997. Regarding the evaluation of distance dependence, it showed a similar trend in general with a difference of 0.035 cm for intensity 50% when compared with the inverse square value. This study suggests the applicability of a digital dosimeter for brachytherapy quality control by evaluating the performance of the HgI₂ dosimeter. This study on dosimeter for candidate photoconductor materials can be used as basic data in all areas using radiation.

• Korean small business review
• /
• v.43 no.2
• /
• pp.1-30
• /
• 2021

This study is to analyze the relationship between supply chain resilience antecedent factors, supply chain resilience and business performance. Supply chain integration, risk management activity, and visibility were selected as the preceding factors of supply chain resilience, and the effect of these factors on agility and robustness as supply chain resilience, and the effects of agility and robustness factors on corporate management performance are studied. To this end, a survey was conducted on Korean manufacturing companies, and a total of 124 questionnaires were used for the study. As a result of the testing of the research hypothesis, supply chain integration, risk management activity, and visibility have a positive (+) significant effect on agility and robustness. In addition, agility had a positive (+) effect on corporate management performance. But robustness had a positive (+) effect on corporate management performance, but not significant. In order for manufacturing companies to secure supply chain resilience through such research hypothesis testing, it is necessary to secure supply chain integration, risk management activity, and visibility capabilities. It was confirmed that agility and visibility capability can be linked to corporate management performance. In addition, the overall relationship structure between the preceding factors of supply chain resilience, supply chain resilience, and business performance was presented.

• Korean Chemical Engineering Research
• /
• v.60 no.3
• /
• pp.327-333
• /
• 2022

In this study, silicon/carbon nanotube/carbon (Si/CNT/C) composites for anode were prepared to improve the volume expansion of silicon used as a high-capacity anode material. Si/CNT were prepared by electrostatic attraction of the positively charged Si and negatively charged CNT and then hydrothermal synthesis was performed to obtain the spherical Si/CNT/C composites. Poly(vinylidene fluoride) (PVDF), polyacrylic acid (PAA), and styrene butadiene rubber (SBR) were used as binders for electrode preparation, and coin cell was assembled using 1.0 M LiPF₆ (EC:DMC:EMC = 1:1:1 vol%) electrolyte and fluoroethylene carbonate (FEC) additive. The physical properties of Si/CNT/C anode materials were analyzed using SEM, EDS, XRD and TGA, and the electrochemical performances of lithium-ion batteries were investigated by charge-discharge cycle, rate performance, dQ/dV and electrochemical impedance spectroscopy tests. Also, it was confirmed that both capacity and rate performance were significantly improved using the PAA/SBR binder and 10 wt% FEC-added electrolyte. It is found that Si/CNT/C have the reversible capacity of 914 mAh/g, the capacity retention ratio of 83% during 50 cycles and the rate performance of 70% in 2 C/0.1 C.

• Journal of Digital Convergence
• /
• v.20 no.5
• /
• pp.393-400
• /
• 2022

In a situation where the company handles accounting conservatively, the management's earnings forecasting information will be more conservative, and the conservativeness of this earnings forecasting information will have a differential effect in evaluating the performance of managers and paying compensation. This study aims to examine how the level of corporate accounting conservatism affects the forecast information of managers and how this affects the compensation of managers. This study establishes a hypothesis on the effect of the level of accounting conservatism on the earnings forecasting information and compensation of managers, and examines the relationship between managerial profit forecasting information & manager compensation according of conservatism in corporate accounting that can vary depending on the manager's disposition. As a result of the analysis, conservative managers are also conservative in earnings forecasting disclosure, and when corporate managers are highly conservative, they show their ability by making earnings forecasts disclosures more frequently and more accurately than corporate managers with low conservatism. It will help reduce the forecasting errors of stakeholders. Therefore, it is expected that this will play an important role in judging the manager's ability and determining compensation. Therefore, when a company handles accounting conservatively, management's earnings forecasts are also measured conservatively, which is expected to provide useful information on the basis and form of management's compensation to stakeholders.

• Journal of the Korea Society of Computer and Information
• /
• v.27 no.10
• /
• pp.11-17
• /
• 2022

In this paper, a model that can increase the efficiency of work in arranging interior furniture by applying augmented reality technology was studied. In the existing system to which augmented reality is currently applied, there is a problem in that information is limitedly provided depending on the size and nature of the company's product when outputting the image of furniture. To solve this problem, this paper presents an AR labeling algorithm. The AR labeling algorithm extracts feature points from the captured images and builds a database including indoor location information. A method of detecting and learning the location data of furniture in an indoor space was adopted using the CNN technique. Through the learned result, it is confirmed that the error between the indoor location and the location shown by learning can be significantly reduced. In addition, a study was conducted to allow users to easily place desired furniture through augmented reality by receiving detailed information about furniture along with accurate image extraction of furniture. As a result of the study, the accuracy and loss rate of the model were found to be 99% and 0.026, indicating the significance of this study by securing reliability. The results of this study are expected to satisfy consumers' satisfaction and purchase desires by accurately arranging desired furniture indoors through the design and implementation of AR labels.

• Journal of Industrial Convergence
• /
• v.21 no.4
• /
• pp.165-170
• /
• 2023

There are cases where the mobility impaired have difficulty moving from the moment they leave the house. If guardians also do not have time to entrust their families, who are socially disadvantaged, to a shelter, the guardian has no choice but to check directly in order to know the location of the guardian. The AI home care solution was designed to relieve the anxiety and labor of caregivers and to provide convenience for protection facility officials and users. If more facilities distribute and use services free of charge to non-profit foundations and protective facilities, the concern of guardians will be reduced, and the burden of facility officials who have to manage facility users will be reduced. In this paper, we provide emergency notification services to guardians in the event of an emergency as well as location and status alarms for guardians, which are all data related to movement, in consideration of the mobility vulnerable. Furthermore, it is necessary to provide a service function that recommends the optimal route using a navigation function to ease the convenience and burden of facility officials. It is necessary to alleviate anxiety by providing necessary information to the guardian, such as the location of the shuttle used by the mobile weak and the time of getting on and off. In addition, while providing services for free, the goal is to improve the quality of service for facility managers and the quality of service for the mobility weak.

• Journal of Navigation and Port Research
• /
• v.47 no.4
• /
• pp.231-238
• /
• 2023

The position of a light buoy is always flexible due to the influence of external forces such as tides and wind. The position can be checked through AIS (Automatic Identification System) or RTU (Remote Terminal Unit) for AtoN. As a result of analyzing the position data for the last five years (2017-2021) of a light buoy, the average position error was 15.4%. It is necessary to detect position error data and obtain refined position data to prevent navigation safety accidents and management. This study aimed to detect position error data and obtain refined position data by DBSCAN Clustering position data obtained through AIS or RTU for AtoN. For this purpose, 21 position data of Gunsan Port No. 1 light buoy where RTU was installed among western waters with the most position errors were DBSCAN clustered using Python library. The minPts required for DBSCAN Clustering applied the value commonly used for two-dimensional data. Epsilon was calculated and its value was applied using the k-NN (nearest neighbor) algorithm. As a result of DBSCAN Clustering, position error data that did not satisfy minPts and epsilon were detected and refined position data were acquired. This study can be used as asic data for obtaining reliable position data of a light buoy installed with AIS or RTU for AtoN. It is expected to be of great help in preventing navigation safety accidents.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.18 no.5
• /
• pp.785-796
• /
• 2023

In this study, a methodology for real-time classification and prediction of defects that may appear in PVDF(Polyvinylidene fluoride) sensors, which are widely used for structural integrity monitoring, is proposed. The types of sensor defects appearing according to the sensor attachment environment were classified, and an impact test using an impact hammer was performed to obtain an output signal according to the defect type. In order to cleary identify the difference between the output signal according to the defect types, the time domain statistical features were extracted and a data set was constructed. Among the machine learning based classification algorithms, the learning of the acquired data set and the result were analyzed to select the most suitable algorithm for detecting sensor defect types, and among them, it was confirmed that the highest optimization was performed to show SVM(Support Vector Machine). As a result, sensor defect types were classified with an accuracy of 92.5%, which was up to 13.95% higher than other classification algorithms. It is believed that the sensor defect prediction technique proposed in this study can be used as a base technology to secure the reliability of not only PVDF sensors but also various sensors for real time structural health monitoring.

• Journal of Korean Dental Hygiene Science
• /
• v.2 no.1
• /
• pp.9-17
• /
• 2019

This study aims to identify the status of oral care of professional soldiers and analyze the relationship between oral care needs and oral health symptoms based on oral health recognition, thus providing an opportunity to create a system for improving oral health of professional soldiers. The study was conducted on a total of 232 military personnel aged 19 or older who were employed in the military. The questionnaire for this study was commissioned to respond by explaining the purpose of the study and how to respond to the survey by telephone with the selected sub-employer. The content included in the questionnaire consisted of general characteristics, oral care status, and awareness of dental hygienists. When the subjective oral health condition was poor, normal, or good, it was all shown that the toothbrush was done more than three times a day, and the oral examination was all examined. In particular, 68.1 percent of the respondents said they were in good subjective health. Preventive treatment was the highest in the group with good subjective oral health. Of the total respondents, 83.6 percent said "yes" to the question of knowing dental hygienists, while 65.5 percent said "yes" to the question of whether they know the work of dental hygienists, recognizing that most of the respondents were aware of dental hygienists and their work. Both the group that said they knew the dental hygienist and the group that said they did not know answered 43.5% as an assistant. In conclusion, oral health projects will have to be carried out in line with military situations in order to maintain a healthy oral state of professional soldiers, and long-term planning for active oral health care, especially as an important role of personnel in charge of health care in the military is needed.

• Journal of the Korea Society of Computer and Information
• /
• v.29 no.4
• /
• pp.63-72
• /
• 2024

The size of the home interior market is growing rapidly as interest in interiors and self-interiors has increased due to the recent rapid increase in single-person households. Most of the Bathroom remodeling is done by requesting an offline interior contractor and then visually checking it in the final completion stage, so it is not easy to re-construct even if the customer is dissatisfied. Therefore, this study developed an immersive virtual reality-based Bathroom self-remodeling system that can visually check space and design from the design stage to the final stage by incorporating VR technology to feel realistic in virtual reality. The bathroom structure may select the basic structure of the predefined bathroom space or freely set the size of the bathroom space. For furniture items, you can choose the washbasin, toilet, bathtub, shower booth that are essential elements of the bathroom and others(mounting rack, trash bin, handle). The tile texture may change the texture of the selected tile at a desired wall position by selecting various textures. In particular,, the texture of the wall tile can be varied by selecting horizontal, vertical and inclined directions at the desired angle according to the needs of the user and the contractor. As a future research project, this system will enable indoor sharing between users who are physically far away in real-time, allowing direct experience in virtual spaces, connection to purchases, and request estimates.