• Journal of Internet of Things and Convergence
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• v.8 no.6
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• pp.55-63
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• 2022

In recent years, with the rapid development of large and medium-sized urban rail transit in China, the total operating mileage of high-speed railway and the total number of EMUs(Electric Multiple Units) are rising. The system complexity of high-speed EMU is constantly increasing, which puts forward higher requirements for the safety of equipment and the efficiency of maintenance.At present, the maintenance mode of high-speed EMU in China still adopts the post maintenance method based on planned maintenance and fault maintenance, which leads to insufficient or excessive maintenance, reduces the efficiency of equipment fault handling, and increases the maintenance cost. Based on the intelligent operation and maintenance technology of PHM(prognostics and health management). This thesis builds an integrated PHM platform of "vehicle system-communication system-ground system" by integrating multi-source heterogeneous data of different scenarios of high-speed EMU, and combines the equipment fault mechanism with artificial intelligence algorithms to build a fault prediction model for traction motors of high-speed EMU.Reliable fault prediction and accurate maintenance shall be carried out in advance to ensure safe and efficient operation of high-speed EMU.

• Economic and Environmental Geology
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• v.53 no.6
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• pp.771-779
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• 2020

This study was performed to develop a priority list for post-managements of leachates from 64 mine waste dump sites in Korea. For this, leachate quality, leachate quantity, and other factors were considered as evaluation criteria and the weights of 10 subfactors were calculated using Analytic Hierarchical Process (AHP) based on a survey from 20 experts in the field of mining environment. Calculated weights were 0.769, 0.147 and 0.084 for leachate quality, leachate quantity, and others, respectively, indicating that experts consider leachate quality as most important. Based on this approach, we classified the 64 mine waste dump sites into five grades from Grade I to Grade V. Ten were classified as Grade I, 1 as Grade II, 1 as Grade III, 33 as Grade IV, and 19 as Grade V.

• Journal of Navigation and Port Research
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• v.44 no.6
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• pp.541-549
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• 2020

This study conducts differential analysis on the financial positions of Korean shipping companies before and after the bankruptcy of the H carrier, looking specifically at their financial ratios, profit and loss patterns, and other factors related to their financial operation. Firstly, it was discovered that major measures of financial health, such as average assets per carrier, were not affected by the bankruptcy of the H carrier. However, despite this, most carriers experienced large changes in profits and losses, with total sales and shipping revenues averaging 424.5 billion won and 381.7 billion won respectively before the bankruptcy, but falling by half to 252.1 billion won and 234.6 billion won after the bankruptcy. Additionally, charter revenues and expenses also dropped by more than half. EBIT/sales and pre-tax revenue margins were also heavily affected after the bankruptcy, with both figures averaging 8% and 3% respectively before the bankruptcy, but falling into the negative range at -2% and -8% post-bankruptcy, resulting in significant deterioration in operational profitability. The study concludes that there is an urgent need to establish a global sales network, improve cost structures, and consistently secure stable cargo in order to increase Korean carriers' profitability. Of all financial measures, liquidity and total asset efficiency were identified as the most severely-impacted by the H carrier bankruptcy, thereby requiring the most pressing policy addressing.

• Korean Journal of Otorhinolaryngology-Head and Neck Surgery
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• v.60 no.8
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• pp.390-395
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• 2017

Background and Objectives With increasing frequency of car accidents, patients of dizziness caused by car accidents are also increasing. Various types of dizziness or vertigo can occur from car accidents depending on different injury mechanisms. Since accurate diagnosis is important for providing proper treatments, we evaluated clinical characteristics related to vestibular function of patients with dizziness caused car accidents. Subjects and Method In this retrospective case review study that runs from January 2011 to March 2013, a total of 82 patients with dizziness following car accident were enrolled consecutively. We analyzed the final diagnosis of dizziness according to different mechanisms of injury during car accident through clinical record review. Patients who developed dizziness within one month of car accident were included, excluding those who had temporal bone fracture and previous history of dizziness. Results Of the different types observed, 36.6% was head injury, 24.4% whiplash injury, 3.7% complex injury, 2.4% others and the rest was unknown. In the final diagnosis, the different types included 36.6% benign paroxysmal positional vertigo (BPPV), 23.2% unclassifiable dizziness, 18.3% cervical vertigo, 7.3% labyrinthine concussion, 3.7% BPPV with labyrinthine concussion and the rest was others. Of the different types of dizziness symptoms, 58.5% was headache, 45.1% was audiologic symptoms, and others included earfullness, tinnitus and hearing disturbance. Tinitogram and pure tone audiogram results show that 2.9% (27 people) of patients have tinnitus and 7.3% (6 people) have hearing disturbance. Conclusion An accurate diagnosis and timely management would be very important in forming a proper approach for post traumatic vertigo patients.

• Journal of Digital Convergence
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• v.18 no.12
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• pp.595-606
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• 2020

To find out the a Study on experiential consumption and development of the customized cosmetics on female university students in their 20s, this study conducted sampling using probability sampling from cosmetics major students in S City from September 1 to October 30, 2020. In this study, a study model was designed for a total of 30 people and studied as an Experience-Consume Experimentation. First, the result of the pre-purchase survey revealed that skincare cosmetics had the highest percentage for being selected by 30 people for "the preferred cosmetic type per the perception regarding customized cosmetics." Second, the result of the pre-purchase survey revealed that 11 people answered skincare cosmetics, 1 person answered shade cosmetics, and 2 people answered fragrance products (perfume, diffusers, etc.) for "the experience type for customized cosmetics." Third, the result of the post-purchase survey revealed that 29 people are willing to recommend the products, while 1 person is not. For the appropriateness of the price, 23 people answered yes; 7 people answered no. for the characteristics of the experience, 24 people (80%) answered that they selected ingredients according to their skin type; 9 people answered that the price is cheap considering they received 1:1 consultation; 18 people answered that they made a choice per their preferences (skin type) rather than per brands; 3 people answered that their self-esteem is stronger as if they received personal care. Therefore, customized cosmetics are expected to increase the attractiveness and purchase rate of female students in their twenties given that 'Human Touch,' genetic analysis, and 'hyper-customization technology,' which requires new development of customized cosmetics experience consumption for female college students in their 20s.

• Journal of Digital Convergence
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• v.18 no.12
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• pp.29-36
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• 2020

The background of this study is that machine learning administrative services are recently attracting attention as a major policy tool for non-face-to-face administrative services in the post-corona era. This study investigated the types of work expected to be effective when introducing machine learning administrative services for Seoul Metropolitan Government officials who are piloting machine learning administrative services. The research method is a machine that can be introduced by organizational unit by distributing and collecting questionnaires for Seoul administrative organizations that have performed machine learning-based administrative services for one month in July 2020 targeting Seoul public officials using machine learning-based administrative services. By analyzing the learning administration service and application service, the business characteristics of each machine learning administration service type such as supervised learning work type, unsupervised learning work type, and reinforced learning work type were analyzed. As a result of the research analysis, it was found that there were significant differences in the characteristics of administrative tasks by supervised and unsupervised learning areas. In particular, it was found that the reinforcement learning domain contains the most appropriate business characteristics for machine learning administrative services. Implications were drawn. The results of this study can be provided as a reference material to practitioners who want to introduce machine learning administration services, and can be used as basic data for research to researchers who want to study machine learning administration services in the future.

• Journal of Applied Biological Chemistry
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• v.64 no.2
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• pp.177-184
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• 2021

While veterinary antibiotics are used only in a part of the dose administered, the rest are excreted as urine or feces. Residual antibiotics enter the adjacent agricultural environments by spraying manure-based composts on farmlands and lead to secondary pollution. Therefore, it is necessary to develop the technique for post management such as regulatory levels of antibiotics in the agricultural environments. This study was conducted to compare by different matrices the amount of residual antibiotics such as tetracyclines and sulfonamides, which are known to be frequently used in Korea and to practice risk assessment by different antibiotics in soils before and after application of composts. Pre-treatment with modified typical method using buffer and solid phase extraction showed the recovery of composts and soils was more than 70% at ppb level and the limits of detection were 0.13-0.46 and 0.05-0.25 ㎍/kg, respectively. Analysis of manure-based composts revealed concentrations from 5.38 to 196.0 ㎍/kg for tetracyclines, from below the detection of limit (BDL) to 259.0 ㎍/kg for sulfonamides. In case of agricultural soils, residual concentrations of selected veterinary antibiotics were ranged 0.30-53.3 ㎍/kg, BDL-4.16 ㎍/kg respectively and the concentration level of tetracyclines, which had higher soil distribution coefficient (Kd) values, was higher than that of sulfonamides. There was a difference in human risk assessment by different antibiotics in soil before and after application of composts. But, it was indicated that detection values of all of 5 antibiotics were very safe on the basis that Hazard Quotient was safe below 1.

• Journal of Digital Convergence
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• v.19 no.6
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• pp.61-71
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• 2021

In a situation where the online learning is expanding due to COVID-19, the current maker education has limitations in applying it to classes. This study is to design the class of online maker education using artificial intelligence tools in elementary school. Also, it is to identify the responses to it and to confirm whether it helps improve the learner's computational thinking and creative problem solving ability. The class was designed by the literature review and redesign of the curriculum. Using interveiw, the responses of instructor and learners were identified. Pre- and post-test using corresponding sample t-test was conducted. As a result, the class consisted of ten steps including empathizing, defining making problems, identifying the characteristics of material and tool, designing algorithms and coding using remixes, etc. For computing thinking and creative problem solving ability, statistically significant difference was found. This study has the significance that practical maker activities using educational artificial intelligence tools in the context of elementary education can be practically applied even in the online environment.

• Journal of Digital Convergence
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• v.19 no.7
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• pp.237-243
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• 2021

This study was attempted to identify the difference between nursing competencies and major satisfaction before and after the first clinical practice of nursing college students and use it as basic data for efficient clinical practice education. Data collection by single group pre- and post-design was conducted from February 18 to April 23, 2019 for 201 nursing college students before and after clinical practice for 8 weeks. The collected data were analyzed by frequency, paried t-test, and Pearson's Correlation, Multiple Regression using SPSS/Win 23.0. As a result of the study, Nursing competency increased after the first clinical practice than before, but it was not significant(t=-1.73, p=.084). Among the sub-factors of nursing competency, educational ability(t=-1.97, p=.050) and ethical practical ability(t=-209, p=.038) was found to increase significantly. Major satisfaction was significantly increased after clinical practice than before(t=-2.45, p=.015). After clinical practice, it was found that general satisfaction, relationship satisfaction, and recognition satisfaction which are sub-factors of major satisfaction, had a positive correlation with nursing competency. As a result of analyzing the impact on nursing competency, it was found that recognition satisfaction explains nursing competency as 9.9%. Therefore, it is necessary to reorganize the clinical practice curriculum that can improve nursing competency, develop a program that can improve major satisfaction, and verify the effectiveness.

• Journal of Convergence for Information Technology
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• v.10 no.12
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• pp.1-8
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• 2020

The purpose of this study was to identify the factors that influence the organizational commitment of clinical dental hygienists to contribute to manpower management. The subject of the study was 195, and the following results were obtained as a result of collecting and analyzing data using a self-filling questionnaire from March 10 to April 20, 2020. The degree of organizational commitment, job satisfaction, and internal marketing according to general characteristics were analyzed by t-test and one-way ANOVA, and post-test was set to'Scheffe'. The correlation between organizational commitment, job satisfaction, and internal marketing showed a significant positive correlation with job satisfaction (r=0.689) and internal marketing (r=0.678). The factors influencing organizational commitment were multiple regression analysis, and the influencing factors for organizational commitment were internal marketing and job satisfaction. The most influential factor was job satisfaction, and the explanatory power was 56.1%.As a result, the internal marketing of clinical dental hygienists was found to be related to job satisfaction and organizational commitment, and the factor that most affected was job satisfaction. Therefore, institutional and administrative support from dental medical institutions is needed to improve job satisfaction, which has an impact on organizational commitment of clinical dental hygienists.