• The Journal of Korea Robotics Society
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• v.17 no.2
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• pp.164-171
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• 2022

Recently, interest of a dual arm robot which can replace humans is increasing in order to improve the working environment and solve the labor shortage. Various studies related with design and analysis of dual-arm robots have been conducted because dual arm robots can have various kinematic configurations according to the objective task. It is necessary to evaluate the work performance according to various kinematic structures of the dual arm robot to maximize its effectiveness. In the paper, the performance analysis is studied according to the shoulder configuration and the wrist configuration of the dual-arm robot by using main performance indices such as manipulability, condition number, and minimum singular value by assigning proper weight values to each objective motion. Performance analysis for the robotic assembly process is effectively carried out for each representative dual arm robot configuration.

• Journal of Korean Institute of Industrial Engineers
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• v.15 no.1
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• pp.77-87
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• 1989

This paper deals with an automated storage carrousel which handles work-in-process(WIP) such as small parts for kitting. The system has been used predominately for order picking applications. Throughput performance of the system can be measured by the inverse of the expected order picking time. Analytic models are developed for approximating the expected times under the "nearest-item" sequencing rule. The performance of the models are tested through computer simulation. The gap between the two is shown to be reasonably small.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.219-224
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• 2012

In this work, a steady-state performance modeling and off-design performance analysis of the 2-spool separate jet turbofan engine named BR715-56 which is a power plant for the narrow body commercial aircraft is carried out for engine performance behaviors investigation and condition monitoring using a commercial code MATLAB/SIMULINK. Firstly, the engine component maps of fan, high pressure compressor, high pressure turbine and low pressure turbine are generated from similar component maps using the scaling method, and then the off-design performance simulation model is constructed by the mass flow matching and the work matching between components. The model is developed using SIMULINK, which has advantages of easy steady-stare and dynamic modelling and user friendly interface function. It is found that the off-design performance analysis results using the proposed model are well agreed with the performance analysis results by GASTURB at various operating conditions.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.6
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• pp.164-169
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• 2000

Recently, High accuracy and precision are required in various industrial field especially, semiconductor manufacturing apparatus, Ultra precision positioning apparatus, Information field and so on. Positioning technology is a very important one among them. As such technology has been rapidly developed, this field needs the positioning accuracy as high as submicron. It is expected that the accuracy of 10nm and 1nm is required in precision work and ultra precision work field, respectively by the beginning of 2000s. High speed and low vibration are also needed. This work deals with the design method and control system of Ultra precision positioning apparatus. Control performance and stability analysis were performed in advance by modeling and designing the controller with Simulink.

• Child Health Nursing Research
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• v.26 no.2
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• pp.131-139
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• 2020

Purpose: This study was conducted to identify factors related to developmental care performance among neonatal intensive care units (NICU) nurses. Methods: The participants were 139 nurses who had provided care to premature infants for more than 6 months and were recruited from the NICU of 8 hospitals. Data were collected from September 1 to December 1, 2017 through questionnaires that encompassed developmental care performance, developmental care perceptions, and the nursing work environment. Results: More than half (51.8%) of the participants responded that they had never received developmental care education, and for 89.6% of those who had received developmental care education, it was a one-time event. The average developmental care performance of NICU nurses was 0.81, with a range of 0.5~1 point. Multiple regression analysis, demonstrated that the nursing work environment (β=.27, p=.001) and developmental care perceptions (β=.23, p=.004) influenced developmental care performance, with a total explanatory power of 14%. Conclusion: Based on these results, developmental care education for the NICU nurses must be provided systematically. In addition, strategies to improve nurses' perceptions of developmental care and to provide appropriate support for the nursing work environment can promote developmental care performance.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.1
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• pp.39-49
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• 2000

This paper presents the modeling approach that can predict transient behavior of rotary compressor. Mass and energy conservation laws are applied to the control volume, real gas state equation is used to obtain thermodynamic properties of refrigerant. The valve equation is solved to analyze discharge process also. Dynamic analysis of vane and roller is carried out to gain friction work. From the above modeling, the performance of rotary compressor with radial clearance and friction loss is investigated numerically. The performance of each refrigerant is estimated, respectively by applying R12, R134a, and R290/ R600a mixture.

• Journal of Korean Critical Care Nursing
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• v.12 no.1
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• pp.13-21
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• 2019

Purpose : The aim of this study was to identify the factors influencing nursing performance in caring for patients with delirium. Methods: This study included 166 nurses who worked for more than 6 months at 4 general hospitals in Jeju Province, South Korea. Patients were administered a self-reported questionnaire. The study was carried out from May 20, 2014, to June 19, 2014. Data analyses were conducted using stepwise multiple regression, Pearson's correlation coefficients, t-test, and analysis of variance using the SAS WIN 9.2 program (SAS Institute, Cary, NC, USA). Results: The factors associated with nurses' performance in delirium care were work position (${\beta}=.22$, t=2.58, p <.001) and having received education on delirium care (${\beta}=.16$, t=2.24, p=.026). Conclusion: The results showed that the nurses' work position and having received education on delirium care affected nursing performance in delirium care. In order to improve nurses' performance in delirium care, hospitals should provide a delirium education program for nurses and establish standard guidelines on delirium care.

• Journal of Families and Better Life
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• v.22 no.5
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• pp.265-281
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• 2004

This study aims at studying dual-earner couple's household work time and life satisfaction in modern times. To reach this goal, dual-earner couple's variable of society and population, income for working hours, attitude of sex's role and working hours time were classified as individual variable of study model. In the end of 2000, positive analysis was completed through dual-earner couples' frequencies, percentage, means, paired-samples T Test, one-way ANOVA, duncan test, multiple regression and path analysis to 112 Korean couples in 'Research material for comparative analysis of family's time use in Korea and in the United States' performed by Lee, Ki-young, along with 3 person in the end of 2000. The time of household work performance at home at this stage is about 30 hours. 90% of 30 hours was given by housewife who was working for another job. In the aspect of dual-earner couple's life satisfaction, the life satisfaction is a little over the level of average. In variables couple's life satisfaction, wife's life satisfaction was additionally influenced by variable of wife's profession, age difference of couple, wife's household work time husband's household work time and wife's sex-role attitudes in oder. Husband's life satisfaction was perfectly influenced by his level of education, his household work time and wife's sex-role attitudes.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.492-499
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• 2022

A large number of employees shifted to Work from home (WFH) due to the COVID-19 pandemic, including the construction workforce. The changes in workload and productivity due to WFH impact the work performance and economic outputs of companies. However, there are mixed results about the impacts of WFH on workload and productivity. In particular, limited studies focused on specific types of work of different occupations in the construction workforce. This study aims to explore the impacts of WFH on workload and productivity considering different types of work for the construction workforce in the U.S. After identifying three main occupations and five types of work, an online survey (N = 69) was distributed. Descriptive analysis showed that participants had less workload (0.82 hours/week) and lower productivity (9.69%) during WFH. Three occupations had varied changes due to the different types of work. Analysis of Variance (ANOVA) indicated that there was no significant difference in workload, while productivity was decreased during WFH. In particular, the productivity of project-related work and communication and documentation decreased significantly. Overall, participants finished 2.85% less workload per week during WFH. The findings provide an insight into WFH in the construction workforce, which improves future remote or hybrid work arrangements in the construction industry.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.3
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• pp.656-663
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• 1990

To investigate the optimum design conditions of Stirling Engines at the preliminary design stage, comparative study between adoabatoc analysis based on an approximate analytical solution to the Ideal Adiabatic Model and the existing isothermal analysis has been carried out. The optimum phase angle obtained from adiabatic analysis to achieve the maximum work with given combination of design parameters is greater than that from isothermal analysis, while the optimum swept volume ratio is smaller. Effect of variation in the temperature ratio on the work parameter is proved to be stronger in adiabatic analysis. On the contrary, the work parameter by adiabatic analysis is less sensitive to a change in the dead volume ratio. Especially in adiabatic analysis there exists the optimum dead volume ratio maximizing the work parameter, which may provide a lower limit of it. Considering that the adiabatic model is more reasonable, signifiant differences between two methods lead to the conclusion that adiabatic analysis is preferable to isothermal one for the preliminary design of Stirling Engines.