• Journal of the Korean Society for Precision Engineering
• /
• v.18 no.12
• /
• pp.104-109
• /
• 2001

With the increase of storage density and data transfer rates in optical disk drive, mechanical issues, mainly noise and vibration, become critical. Rubber materials are extensively used in various machine design application, mainly for vibration/shock/noise control devices. However, there are still a lot of difficulties in the use of designing the rubber components with complex shape and under pre-deformed state. It was demonstrated in that the variation of rubber component stiffness with the pre-deformed state were calculated by the finite element method and the reliability of numerical results were checked by compared with the measuring the deflection values. This paper presents a efficient design method of rubber mounts for anti-vibration of an optical disk thrive. With an empirical equation to estimate elastic modulus from hardness, and dynamic characteristics of rubber material of a cylindrical shape, this method is capable of predicting the dynamic characteristics of rubber components at design stage.

• Journal of The Korean Society of Integrative Medicine
• /
• v.9 no.2
• /
• pp.153-164
• /
• 2021

Purpose : This study aims to assess the impact of the emotional labor on female dental clinic employees' intention to leave, and the moderating effect of internal marketing, reducing the intention to leave and providing basic data for an effective human resources management of dental clinics. Methods : The structured self-administered questionnaires were distributed to dental hygienists, dental assistants and other employees (including administrative staff and dental coordinators, but excluding dentists) working at a dental hospital and at dental clinics in the Busan and Gyeongnam area. This study used SPSS Windows version 18.0 program (Chicago, IL, USA) to perform frequency factor, reliability, correlation, and hierarchical regression analyses were performed using SPSS. Results : First, emotional labor had a positive effect on the intention to leave. Two components of the internal marketing, communication and employee welfare system, had a significant moderating effect on the relationship between employees' emotional labor and their intention to leave, while the education/training component of the internal marketing showed no moderating effect. Conclusion : Enhancement of communication and the employee welfare system will help dental care organizations reduce their employees' emotional labor and hence employees' turnover.

• Journal of Information Technology Services
• /
• v.18 no.2
• /
• pp.75-96
• /
• 2019

These days, many companies use information systems as a basis for organizational management activities and as an important component of sustainable management. Thus, securing and operating a high-quality information system that can improve the efficiency of business processes is a large part of corporate competitiveness. In order to get such a critical information system, it is only possible to successfully carry out the project. Various attempts and studies have been undertaken to increase the success rate of the project. However, the reality is that the success rate is still not getting much better. In this study, the concept of quality of service, which has long been actively studied in marketing area, was applied as a new factor to enhance the project's success. In this study, project performance activities were defined as the act of providing services. A survey of 164 valid collection data was analyzed. The analysis used SPSS 23. Four process quality factors (customer participation, customer response, knowledge and skills, reliability) and 21 metrics were derived. Through this research, I hope to be the starting point of applying process quality concept as a new breakthrough to increase success rate of project.

• The Journal of Economics, Marketing and Management
• /
• v.7 no.3
• /
• pp.1-12
• /
• 2019

Purpose - This study aims to investigate the major capabilities of airline cabin crew to improve the performance of the organization by identifying how they are affected by turnover and customer orientation. Research, design, data, and methodology -The survey participants were limited to all airline cabin crew members in Korea to look at the component measurement items. To verify the validity of the questionnaire, the final questionnaire for this survey was prepared by modifying and supplementing the questionnaire by analyzing factors and validating the questionnaire through reliability verification Results - The analysis on the impact of personal capacity of the airline cabin crew on turnover revealed that some factors had an effect of the positive and the personal capacity of the airline cabin crew has a statistically positive effect on the customer orientation relationship, which is a sub-factor of the cabin crew Conclusions -The capacity of the cabin crew of the airline was defined and the components were established as technical capacity, knowledge capacity and expertise capacity. It was found that the intangible performance of the individual capabilities and customer orientation were very closely related. Airline cabin crew have verified the importance of good talent selection and capacity development training, which are essential requirements for securing the airline's competitiveness.

• The Journal of Asian Finance, Economics and Business
• /
• v.9 no.6
• /
• pp.373-380
• /
• 2022

Today, customer satisfaction is the most important issue for Vietnamese banks. There are numerous factors that influence bank customers' satisfaction. The study investigates the factors that influence customer satisfaction with deposit services at the Vietnam Bank for Agriculture and Rural Development (Agribank) in Bac Giang province, Vietnam, and analyses the impact of each component. The authors used 5-point Likert scales to assess whether elements were related to the factors determining consumer satisfaction with Agribank's deposit service. To perform this study, exploratory factor analysis (EFA) and multiple regression were used to find factors determining customer satisfaction with Agribank services. Customers that use deposit services at Agribank in Bac Giang province, Vietnam, provided samples of 300 survey questionnaires for this study. SPSS software is used to examine the data. Customers' satisfaction with Agribank's deposit service is influenced by six factors, including reliability, responsiveness, service capabilities, empathy, tangible means, and service price, according to the study. This finding also offers some recommendations for improving service quality in local Vietnamese banks to gain a competitive advantage.

• Journal of the Korean Society of Industry Convergence
• /
• v.24 no.3
• /
• pp.283-288
• /
• 2021

A tungsten material using a pressure sintering process and a titanium sintering additive was prepared to evaluate the microstructure, and mechanical properties of flexural strength and hardness. In addition, the reliability on each hardness data was evaluated by analyzing the distribution of the hardness of the tungsten material using the Weibull probability distribution. In particular, the optimal manufacturing conditions were analyzed by analyzing the correlation between the sintering temperature and the mechanical properties of the tungsten sintered body. Although the sintering density of the tungsten material was hardly changed up to 1700 ℃, but it was increased at 1800 ℃. The hardness of the tungsten sintered material increased as the sintering temperature increased, and in particular, the tungsten material sintered at 1800 ℃ showed a high hardness value of about 1790 Hv. It showed relatively excellent flexural strength at a sintering temperature of 1800 ℃.

• Nuclear Engineering and Technology
• /
• v.56 no.1
• /
• pp.141-146
• /
• 2024

Station blackout (SBO) risk is one of the most significant contributors to nuclear power plant risk. In this paper, the sequence probability formulas derived by the convolution approach are compared with those derived by the conventional event tree/fault tree (ET/FT) approach for the SBO situation in which emergency diesel generators fail to start. The comparison identifies what makes the ET/FT approach more conservative and raises the issue regarding the mission time of a turbine-driven auxiliary feedwater pump (TDP), which suggests a possible modeling improvement in the ET/FT approach. Monte Carlo simulations with up-to-date component reliability data validate the convolution approach. The sequence probability of an alternative alternating current diesel generator (AAC DG) failing to start and the TDP failing to operate owing to battery depletion contributes most to the SBO risk. The probability overestimation of the scenario in which the AAC DG fails to run and the TDP fails to operate owing to battery depletion contributes most to the SBO risk overestimation determined by the ET/FT approach. The modification of the TDP mission time renders the sequence probabilities determined by the ET/FT approach more consistent with those determined by the convolution approach.

• Journal of Environmental Health Sciences
• /
• v.42 no.4
• /
• pp.280-292
• /
• 2016

Objectives: The objective of this study was to build COD regression models for the Han River and evaluate water quality. Methods: Water quality data sets for the dry season (as of January) during a four-year period (2012-2015) were collected from the database of the Han River automatic water quality monitoring stations. Statistical techniques, including combined genetic algorithm-multiple linear regression (GA-MLR) were used to build five-descriptor COD models. Multivariate statistical techniques such as principal component analysis (PCA) and cluster analysis (CA) are useful tools for extracting meaningful information. Results: The $r^2$ of the best COD models provided significant high values (> 0.8) between 2012 and 2015. Total organic carbon (TOC) was a surrogate indicator for COD (as COD/TOC) with high reliability ($r^2=0.63$ in 2012, $r^2=0.75$ for 2013, $r^2=0.79$ for 2014 and $r^2=0.85$ for 2015). The ratios of COD/TOC were calculated as 2.08 in 2012, 1.79 in 2013, 1.52 and 1.45 in 2015, indicating that biodegradability in the water body of the Han River was being sustained, thereby further improving water quality. The BOD/COD ratio supported these findings. The cluster analysis revealed higher annual levels of microorganisms and phosphorous at stations along the Hangang-Seoul and Hantangang areas. Nevertheless, the overall water quality over the last four years showed an observable trend toward continuous improvement. These findings also suggest that non-point pollution control strategies should consider the influence of upstreams and downstreams to protect water quality in the Han River. Conclusion: This data analysis procedure provided an efficient and comprehensive tool to interpret complex water quality data matrices. Results from a trend analysis provided much important information about sources and parameters for Han River water quality management.

• Transactions of the Korean Society of Pressure Vessels and Piping
• /
• v.6 no.1
• /
• pp.37-42
• /
• 2010

The stay cylinder weld at the steam generator of Korean Standard Nuclear Power Plants is safety class I component and is subjected to be inspected by the volumetric examination such as ultrasonic method. As accessibility of this area is limited due to the narrow space and high radiation, the existing manual inspection method involves various difficulties. Moreover operators may be exposed to internal contamination by contaminated dust during the surface buffing process to improve the inspection reliability of this area. Recently the new automatic inspection system for stay cylinder welds has been developed. The inspection system basically consists of a driving assembly, data acquisition device and signal processing units. The driving assembly is classified by 1) the scanner for inspecting and buffing the weld, 2) pillars for guiding the scanner and 3) the base frame for loading and supporting pillars. The scanner has 4 sensor modules to inspect in 4 refracted angles and 4 incident directions. These components can be inserted into the skirt of the stay cylinder through the manway hole and assembled easily by one-touch in the skirt. Data acquisition device and signal processing units developed in previous works are also newly upgraded for better processing of data analysis and evaluation. The system has been successfully demonstrated not only in the mock-up but also in the field. In this paper, newly developed inspection system for the stay cylinder weld of the steam generator is introduced and their field applications are discussed.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.37 no.3
• /
• pp.36-42
• /
• 2014

Domestic 105mm HE (High Explosive) shell is composed of three parts that are Fuze, Projectile and Propellants. Among three parts, propelling charge of propellants part consists of single base propellants. It has been known that the lifespan of single base propellants is affected by a storage period. These are because Nitrocellulose (NC) which is the main component of propelling gunpowder can be naturally decomposed to unstable substances similar with other nitric acid ester. Even though it cannot be prevented fundamentally from being disassembled, a decomposition product ($NO_2$, $NO_3$, and $HNO_3$) and tranquillizer DPA (Diphenylamine) having high reactivity are added into a propellant to restrain induction of automatic catalysis by a decomposition product. The decay rate of the tranquillizer is also affected by a production rate of the decomposition product of NC. Therefore, an accurate prediction of the Self-Life is required to ensure against risks such as explosion. Hereupon, this paper presents a new methodology to estimate the shelf-life of single base propellants using data of ASRP (Ammunition Stockpile Reliability Program) to domestic 105mm HE (propelling charge of propellants part). We selected four attributes that are inferred to have influence on distribution of the DPA amount in a propellant from the ASRP dataset through data mining processes. Then the selected attributes were used as independent variables in a regression analysis in order to estimate the shelf-life of single base propellants.