• Journal of Korean Tunnelling and Underground Space Association
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• v.23 no.6
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• pp.517-534
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• 2021

Hydrogen fuel is emerging as an new energy source to replace fossil fuels in that it can solve environmental pollution problems and reduce energy imbalance and cost. Since hydrogen is eco-friendly but highly explosive, there is a high concern about fire and explosion accidents of hydrogen fueled vehicles. In particular, in semi-enclosed spaces such as tunnels, the risk is predicted to increase. Therefore, this study was conducted on the applicability of the equivalent TNT model and the numerical analysis method to evaluate the hydrogen explosion pressure in the tunnel. In comparison and review of the explosion pressure of 6 equivalent TNT models and Weyandt's experimental results, the Henrych equation was found to be the closest with a deviation of 13.6%. As a result of examining the effect of hydrogen tank capacity (52, 72, 156 L) and tunnel cross-section (40.5, 54, 72, 95 m²) on the explosion pressure using numerical analysis, the explosion pressure wave in the tunnel initially it propagates in a hemispherical shape as in open space. Furthermore, when it passes the certain distance it is transformed a plane wave and propagates at a very gradual decay rate. The Henrych equation agrees well with the numerical analysis results in the section where the explosion pressure is rapidly decreasing, but it is significantly underestimated after the explosion pressure wave is transformed into a plane wave. In case of same hydrogen tank capacity, an explosion pressure decreases as the tunnel cross-sectional area increases, and in case of the same cross-sectional area, the explosion pressure increases by about 2.5 times if the hydrogen tank capacity increases from 52 L to 156 L. As a result of the evaluation of the limiting distance affecting the human body, when a 52 L hydrogen tank explodes, the limiting distance to death was estimated to be about 3 m, and the limiting distance to serious injury was estimated to be 28.5~35.8 m.

• Journal of the Korea Knowledge Information Technology Society
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• v.13 no.1
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• pp.11-23
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• 2018

This paper empirically investigates the factors that influence the consumer choice of an app market based on the rational choice theory. The app market is the only channel where a consumer can buy smartphone apps, which give various functional convenience and are considered to be a major contributor to the proliferation of smartphones. Analyses of 281 questionnaires show that usability and structural guarantees as benefit factors significantly influence the app market choice. From the cost perspectives, both monetary and non-monetary conversion costs are found to significantly influence the app market choice. On the other hand, customer trust, information quality, and market image were found to have no significant effect on app market selection. In particular, Korean app market platform providers (KT, LG U +) seem to be superior in terms of structural guarantees, such as customer center operation and damage compensation regulations, compared to overseas app market platform operators (Google). However, in the case of the Google App Market, it is pre-installed on all Android phones, so it is not inconvenient to install additional apps to use other app market. This is disadvantageous to domestic app market platform operators, and it is necessary to establish a policy solution point. In terms of operator costs, both monetary and non-monetary conversion costs have a significant impact on app market choice. In particular, non-monetary conversion costs have a negative impact on Korean app market platform operators. It can be explained that the service expectation level of the domestic app market is low and it is recognized that the time cost factor such as membership is large for new users to use. It seems to be necessary to improve the domestic app market business. Meanwhile, extant research on smartphone apps focuses on the purchase of apps themselves, but not on the selection of the app market itself. In order to fill in this gap, this study focuses on the determinants of app market selection, including the characteristics of an app market and the switching costs.

• Korean Journal of Clinical Laboratory Science
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• v.51 no.3
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• pp.360-369
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• 2019

Cadherins are essential transmembrane proteins that promote cell-cell adhesion and maintain the corpus luteum structure in the ovary. This study examined the influence of prostaglandin F2 alpha ($PGF2{\alpha}$) on E-cadherin, N-cadherin, and adhesion in luteal theca cells (LTCs). The luteal cells were isolated from the mid-phase corpus luteum, and the LTCs were cultured separately from the luteal heterogeneous cells according to the morphology of the mesenchymal cells and to determine if steroidogenic and endothelial cells of LTCs, 3beta-hydroxysteroid dehydrogenase ($3{\beta}$-HSD), and vascular endothelial growth factor receptor 2 (VEGFR2) mRNA were used. The LTCs were then incubated in the culture medium supplemented with 0.01, 0.1, and 1.0 mM $PGF2{\alpha}$ for 24 h, and the E-cadherin and N-cadherin proteins in the LTCs were detected by confocal laser scanning microscopy. The results revealed $3{\beta}$-HSD mRNA expression in the LTC but no VEGF2R mRNA expression. The E-cadherin and N-cadherin proteins of the LTCs were damaged in the 0.01, 0.1, and 1.0 mM $PGF2{\alpha}$ treatment groups, and the expression of the N-cadherin protein was reduced significantly in 0.01 mM $PGF2{\alpha}$ compared to the 0 mM $PGF2{\alpha}$ treatment groups (P<0.05). In addition, the number of attached LTCs were significantly lower in the 0.01 mM $PGF2{\alpha}$ treatment group than in the 0 mM $PGF2{\alpha}$ treatment group (P<0.05). In conclusion, $PGF2{\alpha}$ affected the disruption of cadherin proteins and cell adhesion in LTCs. These results may help better understand the cadherin and adhesion mechanism during corpus luteum regression in the ovary.

• Journal of Physiology & Pathology in Korean Medicine
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• v.36 no.4
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• pp.138-142
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• 2022

This study aimed to evaluate the effectiveness of Korean rehabilitation treatement for patients with post-TKR. The medical records of inpatients undergoing Korean rehabilitation treatment after TKR from 2016.01.01. to 2021.12.31. during the admission, were analyzed retrospectively. The effect of treatment was evaluated by using a numeric rating scale(NRS) and range of motion(ROM) of knee. Statistical analysis was done using the IBM SPSS statistics 26 program. If the period of hospitalization was within 7 days or change of NRS and ROM was not recorded properly, the case was excluded. All inpatients received acupuncture treatment, Electro-acupuncture. Soyeom pharmaco-acupuncture were used at a high rate. Blood letting cupping therapy, dry cupping therapy, Interferential Current Therapy(ICT) continuous passive motion(CPM), cryotherapy were used at a high rate. A significant improvement was noted when comparing the NRS and knee ROM results at the time of admission and discharge. Korean medical rehabilitation can be effectively used for patients who have undergone TKR, to relieve pain and enable returning to daily activities. It is expected to be helpful in future studies of post-TKR in Korean Medicine. Also It can be used for medical treatment of post-TKR in Korean Medicine Hospital and clinic. However, further research with a high level of evidence is necessary to support this finding.

• The Journal of the Society of Stroke on Korean Medicine
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• v.23 no.1
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• pp.73-84
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• 2022

■Objective The purpose of this case report is to report the effect of Korean medicine treatment on a patient with pontine infarction complaining of discomfort due to aggravated voiding dysfunction after the onset of the stroke. ■Methods The patient was hospitalized for 44 days and treated with herbal medicine, acupuncture, electroacupuncture, moxibustion, and interferential current therapy(ICT). We checked the amount of self-voided volume and postvoid residual urine volume(PVR), and asked the patient to subjectively evaluate the degree of discomfort due to voiding dysfunction. ■Results After 44 days of hospitalization, the patient responded that the subjective discomfort due to residual urine remained 30% and delayed urine remained 50% compared to the day of admission. The maximum amount of PVR was 234 ml on the 3^rd day, and the minimum amount of PVR was checked on 25^th and 35^th day as 0 ml. ■Conclusions This study suggests that Korean medicine treatment may be effective in the treatment of voiding dysfunction after stroke.

• Journal of radiological science and technology
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• v.28 no.3
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• pp.193-201
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• 2005

We are living in Ubiquitous society now. There is also trend of integration in medical field that is largely affected by outside environment. At this time, it is necessary to rightly understand the abstract, function, expected effect and management method of Integration Medical Information System(IMIS) to use this system effectively for solving many hospital information system problems and disadvantages. It is fact that large-sized hospitals are improving the quality of service for treatment of patients through building integrated Medical Information System. So it is necessary to change this individual system that is previously developed and used for treatment assistance, hospital affair or general management respectively to integrated management system, modify patient information or treatment information data to the data suitable for new system and build the integrated medical information system suitable for the hospital service with treatment data and integrated medical information. This paper suggested and designed abstract of integrated medical information system, the organization of system, the character of system and the plan and materialization of IMIS when building integrated medical information system. And the context of this paper is suggested trend of industry and solution of integration EMR, HIS, PACS. Therefore this paper is suggested development strategy, implemented integration medical information system.

• Journal of Korea Water Resources Association
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• v.53 no.spc1
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• pp.813-826
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• 2020

This study analyzes the effects of the Smart Water City (SWC) project that was introduced from 2014 to 2016 in Paju City, Gyeonggi Province, Korea, focusing on the achievement of the business goals. The SWC is referred to as a city that embraces a healthy water supply system based on Smart Water Management (SWM) that promotes the efficiency of water management by combining Information and Communication Technologies (ICTs) with water and sewerage facilities. In order to evaluate the effectiveness of the SWC project, this study deploys evaluation criteria corresponding to the project objectives, and analyzes the outputs before and after the project. The results show that the SWC has contributed to enhancing water supply services and the reliability and drinking rate of tap water. Specific improvement areas include the rise of average water flow rate and water leakage reduction, the diffusion of water quality monitoring system, and the reduction of floating particle concentration and turbidity in drainage pipes was achieved. These were possible because of specific implementation plans for clear goal setting and achievement and active services for citizens. The data related to water quantity and quality showed improved performance compared to before the introduction of SWMS, which is a positive effect. However, a quantitative analysis of the outputs has limitations in identifying other external factors that have led to the changes. In the future, guidelines for spreading SWC and more comprehensive and specific evaluation indicators for SWC should be prepared, and SWMS should be developed in consideration of the needs of users.

• The Journal of the Acoustical Society of Korea
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• v.41 no.5
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• pp.492-499
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• 2022

This study experimentally investigates the effect of dimensionality reduction of vibration signal on fault diagnosis of a marine engine. By using the principal component analysis, a vibration signal having the dimension of 513 is converted into a low-dimensional signal having the dimension of 1 to 15, and the variation in fault diagnosis accuracy according to the dimensionality change is observed. The vibration signal measured from a full-scale marine generator diesel engine is used, and the contribution of the dimension-reduced signal is quantitatively evaluated using two kinds of variable importance analysis algorithms which are the integrated gradients and the feature permutation methods. As a result of experimental data analysis, the accuracy of the fault diagnosis is shown to improve as the number of dimensions used increases, and when the dimension approaches 10, near-perfect fault classification accuracy is achieved. This shows that the dimension of the vibration signal can be considerably reduced without degrading fault diagnosis accuracy. In the variable importance analysis, the dimension-reduced principal components show higher contribution than the conventional statistical features, which supports the effectiveness of the dimension-reduced signals on fault diagnosis.

• Knowledge Management Research
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• v.22 no.1
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• pp.309-330
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• 2021

The information security disclosure system (ISDS) has been implemented since 2016 to ensure the protection of stakeholders and the right to know, and to promote voluntary investment in information protection by companies. Regarding the information security disclosure system, there have been studies that urge the implementation of the system, but studies that analyze the contents disclosed after the implementation of the system or suggest improvement directions are few. In this study, the contents of the information security disclosure system that had been announced on the information security industry promotion portal until 2019 were analyzed, the current status was summarized, and the direction of system improvement was suggested. In some cases, companies that disclosed information through the disclosure system increased the number of personnel in charge and obtained certifications related to information security, but did not find any effect on the increase/decrease in investment. The current disclosure system has not been activated because it has difficulty in giving individual companies incentives to disclose. Thus, this study suggests the inclusion of ISDS to information security management system (ISMS), which is currently mandatory for certain companies. In the current disclosure system, it is difficult for the company's stakeholders or customers to check the contents of the disclosure. As a way to do this, a method of including in the contents of the personal information processing policy or the notification of the use of personal information was suggested.

• Knowledge Management Research
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• v.22 no.3
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• pp.173-199
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• 2021

As the use of smart devices such as smartphones and tablets has become common, the time to start using smart devices is getting earlier, such as using smart devices from the age of one. Also, the use of smart devices by infants and toddlers is continuously increasing. Smart devices have become convenient means of acquiring pleasure and knowledge, but the side effects of addiction and overdependence are becoming issues as much as the benefits of smart devices. This study pays attention to young children's overdependence on smart devices, and focuses on the aspects of parents' perception, control, and observational behavior about smart devices, which can have a profound effect on young children. This study examines how young children's overdependence on smart devices can consequently affect children's characteristics in terms of activity, emotional sensitivity, and social aspects. In particular, this study attempts to explore that the factors influencing children's overdependence on smart devices and the results can vary depending on the moderating variables (parents' control method for children's smart device use, supervision method, and type of contents mainly used). Based on the findings, this study can provide guidelines and implications for parents on how to effectively use smart devices for their young children.