• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.705-713
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• 2021

Because the cage assembly serves as the launch platform, an accurate aim is essential to ensure shooting accuracy for the target. On the other hand, the abnormal rotation of the cage due to the directional errors of the K-MLRS has continuously caused quality problems. The quality problem of weapon systems may have a negative impact on the military's power loss. In this study, improvement plans were derived by examining the defects and analyzing the directional errors of the K-MLRS launcher. In addition, all possible causes of directional errors were derived from the flow diagram for cage directionality. Based on the results, the defense design through the software program was intended to prevent the loss of direction. Through this study, the signal error of the resolver was improved by preventing unspecific signals in the data. Furthermore, the directional judgment method was improved to minimize the impact of data distortion. Lastly, directional storage and verification methods were improved so that data for the cage rotation direction would not be affected by errors. For the design improvement method, the reliability was verified through the system applicability. This study is expected to be a reference for failure analysis and design for similar weapon systems in the future.

• Quality Improvement in Health Care
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• v.27 no.2
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• pp.18-29
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• 2021

Purpose: Patients with hematologic malignancy (HM) typically have a high mortality rate when their condition deteriorates. The chronic progressive course of the disease makes it difficult to assess the effect of intervention on acute events. We investigated the effectiveness of a rapid response team (RRT) on in-hospital mortality in patients with HM. Methods: We retrospectively analyzed the data of patients with HM who admitted to the medical intensive care unit between 2006 and 2015. Clinical outcomes before and after RRT implementation were evaluated. Results: A total of 228 patients in the pre-RRT period and 781 patients in the post-RRT period were included. The overall in-hospital mortality was 55.4%. Patients in the post-RRT period had improved survival; however, they required more vasopressor therapy, continuous renal replacement therapy, and extracorporeal membrane oxygenation. Multivariate analysis revealed that in-hospital mortality was associated with RRT activation (hazard ratio [HR], 0.634; 95% confidence interval [CI], 0.498-0.807; p < .001), neurological disease (HR, 2.007; 95% CI, 1.439-2.800; p < .001), sequential organ failure assessment score (HR, 1.085; 95% CI, 1.057-1.112; p < .001), need for continuous renal replacement therapy (HR, 1.608; 95% CI, 1.206-1.895; p< .001), mechanical ventilation (HR, 1.512; 95% CI, 1.206-1.895; p< .001), vasopressor (HR, 1.598; 95% CI, 1.105-2.311; p = .013), and extracorporeal membrane oxygenation (HR, 1.728; 95% CI, 1.105-2.311; p = .030). Conclusion: RRT activation may be associated with improved survival in patients with HM.

• The Journal of the Korea Contents Association
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• v.22 no.4
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• pp.145-158
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• 2022

Although the rapid development of technology has led to a swift increase in the number of companies using social networking services (SNS), it will not be accurate to say that they have fully "utilized" the functionality of SNS simply by "using" these services. Therefore, this study aims to increase the convenience of using digital technology and help SNS users in extending the functionality of these services beyond their regular use and thus, revitalize the field by increasing the service providers' efficiency. In this study, the Facebook usage status of a graduate school newspaper from an undisclosed university in Seoul was analyzed from February to December, 2021 using the participant observation method. The results of the study revealed the following: First, it is necessary to diversify the subject and type of content to ensure a continuous supply of quality content; Second, there is a need to examine the user categories and characteristics by utilizing SNS functionalities such as, the target reports and insights, and based on this, supply content that meets the needs of the users; Third, to resolve the problem of low levels of user participation and an inactive Facebook account, it is necessary to mobilize new marketing tools like online events. The significance of this study is that it confronts the real problems faced by some companies that cannot keep pace with market changes in a digital environment, identifies failure factors, and proposes solutions to them.

• Journal of the Microelectronics and Packaging Society
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• v.29 no.2
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• pp.49-52
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• 2022

As the difficulty of flip chip products increase, interest in stable PKG material technology from the viewpoint of reliability is increasing. Currently, the representative of poor reliability that are mainly occurring in flip chip PKG are Sn bridge and Cu dendrite. Two type defects are caused by void generated by the flux residue around the bump. In order to essentially minimize the risk of this type of reliability failure, the linkage between the composition of Molded Under-fill (MUF) and flux, which is related material, was reviewed. In this study, the correlation between base resin and filler, which is the main component of MUF, and flux, was defined, and the material composition design was carried out by refer to lesson learn. With the current material composition, it was confirmed that moisture absorption reliability 85%/85%/24hrs pass result and void did not occur during destructive analysis, and developed MUF has shown flux immunity improving result in flip Chip PKG. We think this study can be used in yield enhancement of flip chip process and give insights to study in compatibility between MUF and flux.

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.1
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• pp.57-78
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• 2022

The disc cutter and cutterbit, which are the most important factors to increase the excavation efficiency of TBM, are key factors in the design and construction of the cutter head. The arrangement, spacing, number, size, and material of disc cutters suitable for the ground conditions determine the success or failure of TBM construction. The disc cutter, which is a representative consumable part in TBM construction, can cause enormous disruption to the construction cost as well as the construction cost unless accurate prediction of wear and replacement cycle is accompanied. Therefore, in this study, the method of calculating the replacement cycle of the disc cutter calculated at the time of design for the slurry shield TBM field, and the depth of wear and replacement location of the disc cutter that occurred during actual construction were compared by analyzing the field data. For a quantitative comparison, weathered soil/weathered rock, soft rock, and hard rock were classified according to the ground in the section showing constant excavation data, and the trajectory of circle was different depending on the location of the disc cutter, so it was compared and analyzed.

• The Journal of Engineering Geology
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• v.31 no.4
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• pp.561-577
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• 2021

The ten standard roughness profiles suggested by Barton and Choubey (1977) were extended to make three-dimensional (3D) joint models whose profiles were identical at any cross section. Replicas of joint models were produced using plaster of Paris, and direct shear tests were performed to verify the joint roughness coefficients (JRC) of the standard roughness profiles. Joint shear strengths measured by direct shear tests were compared with those predicted by the shear failure criterion suggested by Barton (1973) based on JRC, joint compressive strength (JCS), and joint basic friction angle (𝜙_b). Shear strengths measured from joints of the first and fourth standard roughness profiles were close to predicted values; however, shear strengths measured from the other joint models were lower than predicted, the differences increasing as the roughness of joints increased. Back calculated values for JRC, JCS, and from the results of the direct shear tests show measured shear strengths were lower than predicted shear strengths because of the JRC values. New JRC were back calculated from the measured shear strength and named JRC_m. Values of JRC_m were lower than the JRC for the standard roughness profiles but show a strong linear relationship to JRC. Corrected JRC_m values for the standard roughness profiles are provided and revised relationships between JRC_m and JRC, and new shear strength criterion are suggested.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.16 no.6
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• pp.269-285
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• 2021

As the systematic management of knowledge within an organization is recognized as a core factor for the continuous growth of an organization, organizations are increasing their interest in knowledge management. Knowledge management requires the active sharing of knowledge by insiders of the organization, but there are cases of failure due to the lack of participation of leaders and employees of the organization. The purpose of this study is to suggest a mechanism by which the authentic leadership of leaders in small and medium-sized enterprises(SME), which are relatively lacking in knowledge production capacity, leads to intention to share knowledge of employees. In addition, the study confirms that reciprocal feedback and task interdependence moderate the relationship between antecedent factors and intention to share knowledge. In this study, a research model was derived based on precedent research, and 272 samples were obtained by conducting a questionnaire survey on employees of SME that introduced a knowledge management policy. And, the study verified the hypothesis by applying structural equation modeling based on AMOS 22.0. The results of the study proved that authentic leadership has a positive effect on the intention to share knowledge through organization identification and organization commitment, and confirmed that reciprocal feedback and work interdependence moderate the relationship between knowledge sharing intentions and antecedent factors. This study suggests the mechanism by which the authentic behavior of the leaders of SMEs affects the knowledge sharing behavior of employees, and suggests that work cooperation strengthens the influence of the mechanism.

• Journal of the Korean Geosynthetics Society
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• v.21 no.4
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• pp.101-109
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• 2022

This study describes the results of model experiment to analyze the effect of backfill material types on the behavior of underground facility. In the model experiment, backfill materials around the existing underground facility were applied with soil (Jumunjin standard sand) and CLSM. The displacement of underground facility was analyzed for each excavation stage considering the separation distance between the excavation surface and the backfill area based on the experimental results. When soil was applied as a backfill material, the soil on the back of the excavation surface collapsed by excavation and formed an angle of repose, and the process of slope stability was repeated at each excavation stage. In addition, the displacement of underground facility began to occur in the excavation stage that the failure line of soil passes the installation location of the underground facility. When CLSM was applied as a backfill material, there was almost no horizontal and vertical displacement of the ground regardless of the separation distance from the excavation surface even when excavation proceeded to the backfill depth. Therefore, this result showed that it can have a resistance effect against the lateral earth pressure generated and the collapse of the original ground by adjacent excavation, if a backfill material with high stiffness such as CLSM is applied.

• Journal of Navigation and Port Research
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• v.46 no.6
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• pp.562-569
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• 2022

The alarm monitoring technology applied to existing operating ships manages data items such as temperature and pressure with AMS (Alarm Monitoring System) and provides an alarm to the crew should these sensing data exceed the normal level range. In addition, the maintenance of existing ships follows the Planned Maintenance System (PMS). whereby the sensing data measured from the equipment is monitored and if it surpasses the set range, maintenance is performed through an alarm, or the corresponding part is replaced in advance after being used for a certain period of time regardless of whether the target device has a malfunction or not. To secure the reliability and operational safety of ship engine operation, it is necessary to enable advanced diagnosis and prediction based on real-time condition monitoring data. To do so, comprehensive measurement of actual ship data, creation of a database, and implementation of a condition diagnosis monitoring system for condition-based predictive maintenance of auxiliary equipment and piping must take place. Furthermore, the system should enable management of auxiliary equipment and piping status information based on a responsive web, and be optimized for screen and resolution so that it can be accessed and used by various mobile devices such as smartphones as well as for viewing on a PC on board. This update cost is low, and the management method is easy. In this paper, we propose CBM (Condition Based Management) technology, for autonomous ships. This core technology is used to identify abnormal phenomena through state diagnosis and monitoring of pumps and purifiers among ship auxiliary equipment, and seawater and steam pipes among pipes. It is intended to provide performance diagnosis and failure prediction of ship auxiliary equipment and piping for convergence analysis, and to support preventive maintenance decision-making.

• Journal of Korean Medicine Rehabilitation
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• v.32 no.3
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• pp.1-11
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• 2022

Objectives This study was designed to evaluate the healing effect of Cordyceps Militaris (CM) on collagen II-induced arthritis rats. Methods Sprague-Dawley rats were randomly divided into 6 groups (normal, control, positive control, CM with low/medium/high dosage each). Type II collagen mixed with complete Freund's adjuvant (with 1:1 v/v) was injected subcutaneously, and the mixture was injected in a same manner one week after the first injection to boost arthritis. Arthritis index, paw thickness and von Frey test were conducted to observe physical changes. hematoxylin and eosin (H&E) staining was performed to observe knee cartilage. The levels of messenger RNA (mRNA) expressions of interleukin (IL)-1𝛽, IL-6, tumor necrosis factor-alpha (TNF-𝛼) in spleen were assessed by real-time polymerase chain reaction. Results Rheumatoid arthritis is an autoimmune disease that occurs on multiple joints and can lead to temporary shape change of bones or organ failure in severe cases. Here, we aimed to determine the effect of CM extract on rheumatoid arthritis by measuring paw thickness, arthritis index, conducting von Frey test and H&E staining, and evaluating the level of IL-1𝛽, IL-6, TNF-𝛼. As a result, paw thickness, arthritis index significantly decreased in low concentration group, hind leg became less sensitive in all expermental groups. Also, histological analysis showed that the damage of knee cartilage was prevented in all experimental groups. The level of mRNA of IL-1𝛽, IL-6, and TNF-𝛼 in spleen was analyzed to decide the effectiveness of CM extract. IL-1𝛽 did not show significant change, but IL-6 and TNF-𝛼 showed significant decrease in at least one of the experimental groups. Conclusions CM showed protective effect on knee tissue destruction and improved the physical conditions of the leg involving arthritis. Also, it showed that CM has anti-inflammatory effect on specific cytokines inducing rheumatoid arthritis. In conclusion, this study demonstrated that the therapeutic potential of CM for the treatment rheumatoid arthritis, and set the foundation for the further studies.