• Proceedings of the KIEE Conference
• /
• 2000.11a
• /
• pp.214-216
• /
• 2000

This paper presents an comparative study on the effect of STATCOM and UPFC to the power system static analysis. The effect of STATCOM can be analyzed with PSS/E program which is generally used in power system analysis, while UPFC model for static analysis is not provided yet. Thus, UPFC is equivalently represented as a synchronous condenser and load, while the active and reactive power of the specific transmission line and the voltage of the bus is controlled appropriately. This procedure is implemented by IPLAN which is an external macro program of PSS/E. The simulation results show that UPFC is more effective to control the bus voltage than STATCOM, because UPFC can control not only the bus voltage where the parallel inverter is installed but also the active and reactive power flow in the transmission line where the series inverter is installed.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.14 no.2
• /
• pp.339-348
• /
• 1990

Techniques which are able to predict and control dynamic characteristics, not affecting the vibrational characteristics on the modification of structural design, are being studied. As one of these techniques, experimental modal analysis is widely applied by many researchers. In this study, modal analysis is performed using transfer matrix method by a macro computer. The developed program would estimate the structural modal parameters precisely, and the validity of this program is certified by comparing with the experimental results of .GAMMA A. structure. Estimated modal parameters(natural frequency, vibrational mode, equivalent mass, etc.) are in accord with the experimental results. Also, the optimal location of the additive mass is determined by the evaluation of the vibrational mode and the equivalent mass. The relation between the additive mass and the equivalent mass is specified, and we come to know that the ratio of equivalent mass to additive mass alter linearly within the range of 20%.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.20 no.5
• /
• pp.67-81
• /
• 2017

Because of lack of accurate understanding of the mechanism of urban heat island (UHI) phenomenon and lack of scientific discussion, it is hard to come up with effective measures to mitigate UHI phenomenon. This study systematically described the UHI and suggested the solutions using green-infrastructure (green-infra). The factors that control UHI are very diverse: radiant heat flux, latent heat flux, storage heat flux, and artificial heat flux, and the air temperature is formed by the combination effect of radiation, conduction and convection. Green-infra strategies can improve thermal environment by reducing radiant heat flux (the albedo effect, the shade effect), increasing latent heat flux (the evapotranspiration effect), and creating a wind path (cooling air flow). As a result of measurement, green-infra could reduce radiant heat flux as $270W/m^2$ due to shadow effect and produce $170W/m^2$ latent heat flux due to evaporation. Finally, green-infra can be applied differently on the macro(urban) scale and micro scale, therefore, we should plan and design green-infra after the target objects of structures are set.

• Proceedings of the KIEE Conference
• /
• 2001.07a
• /
• pp.155-157
• /
• 2001

This paper presents an comparative study on the effect of SSSC and UPFC to the power system static analysis. SSSC is used to control active power flow in transmission lines by controlling the phase angle of the injected voltage source which is in rectangular to the line current. UPFC is used to control the magnitude and phase of the injected voltage sources which are connected both in series and in parallel with the transmission line to control power flow and bus voltage. To compare the effect of SSSC and UPFC in power system static analysis, the PSS/E simulation program is used. As the FACTS device model such as SSSC and UPFC is not provided in PSS/E yet, an equivalent load model is used. This procedure is implemented by IPLAN which is an external macro program of PSS/E. The simulation results show that UPFC is more effective to improve bus voltage than SSSC in power system static analysis.

• Proceedings of the KIEE Conference
• /
• 2007.07a
• /
• pp.578-579
• /
• 2007

The importance and necessity of conducting studies on area outage cost assessment have been increasingly important in recent years due to the competitive electricity market environment. The objective of operational issues would be to minimize the total area cost while satisfying all associated system constrains of each area[2]. This paper presents a methodology of the Area annual outage cost assessment by probabilistic reliability evaluation using TRELSS program for KEPCO system. The interrupted energy assessment rate (IEAR) is evaluated by macro approach that is using relations between GRDP and the electrical energy demand. The Expected Energy Not Supplied (EENS) of each area was evaluated using the Transmission Reliability Evaluation for Large-Scale Systems (TRELSS) Version 6_2, a program developed by EPRI are introduced in this paper.

• Journal of muscle and joint health
• /
• v.30 no.1
• /
• pp.36-47
• /
• 2023

Purpose: The study aim was to investigate factors affecting factors nursing performance. Methods: This descriptive correlation study examined degree of mindfulness, resilience, organizational commitment, and nursing performance in order to confirm the correlation between variables and their effects on nursing performance. Study participants were 193 nurses who had more than 1 year of work experience at a tertiary hospital. The data were collected from March to April 2022 using structured self-reported questionnaires. SPSS/WIN 25.0 program was used to analyze the data. The statistical significance of the mediating effects were verified by applying PROCESS Macro. Results: Resilience, health state, total clinical career years, and organizational commitment were identified as factors affecting nursing performance, with the model explaining 51.6% of outcomes. Resilience had a complete mediating effect on the relationship between mindfulness and nursing performance. Conclusion: To improve nursing performance, various education and training must be developed and implemented to strengthen resilience. Additionally, it will be helpful to apply a mindfulness-based program to improve resilience. Further, designing various measures to improve the work environment and increase organizational commitment is recommended.

• Korean Journal of Childcare and Education
• /
• v.19 no.2
• /
• pp.1-20
• /
• 2023

Objective: The present study aimed to investigate the sequential mediation effects of creative home environment and preschoolers' playfulness on the relationship between mothers' play beliefs and preschoolers' happiness. Methods: The subjects of this study were 233 preschoolers between the ages of 3 and 5 and their mothers. Mothers were asked to complete a questionnaire that assessed their beliefs about play, the creative home environment they provided, as well as their child's playfulness and happiness. The data collected were analyzed using the SPSS Process Macro program to investigate the sequential mediating effects. Results: The study found that the mothers' play support beliefs were directly associated with their preschoolers' happiness. Additionally, the creative home environment was found to mediate the relationship between the mother's play beliefs and their preschooler's happiness. The children's playfulness was also identified as a mediator in the relationship between the mother's play beliefs and their preschooler's happiness. Furthermore, the findings of this study indicated that the relationship between the mother's play beliefs and preschoolers' happiness was sequentially mediated by the creative home environment and preschoolers' playfulness. Conclusion/Implications: Findings of this study provide insights into the potential development of a parent education program aimed at modifying mothers' play beliefs and the home environment.

• Journal of Digital Convergence
• /
• v.19 no.11
• /
• pp.95-112
• /
• 2021

This study analyzed the effects of healing agriculture program types on program satisfaction by using functional image and emotional image of the program as mediators for the participants of healing agriculture program. The sub-variables of the healing agriculture program were classified into horticultural healing, animal healing, food healing, and forest healing. 328 questionnaires collected from the participants of healing agriculture program in the whole country were used for empirical analysis, which used SPSS v22.0 and PROCESS macro v3.4 to analyze the parallel multiple mediation model. First, Among the types of healing agriculture programs, animal healing, food healing, and forest healing had a positive (+) effect on functional image. Second, all types of healing agriculture program had a positive (+) effect on emotional image. Third, both functional and emotional images had a significant positive effect on satisfaction. Fourth, among the types of healing agriculture program, horticultural healing, animal healing, and forest healing had a significant effect on satisfaction, while food healing did not maintain the significant effect on satisfaction. Fifth, functional image mediated between healing agriculture program and satisfaction. Sixth, emotional image mediated between healing agriculture program type and satisfaction. In the next study, it is necessary to study for the adjustment of mediators other than the mediators introduced in this study or the controlled mediated analysis through the conditional process model in which the moderator variable is introduced.

• Proceedings of the Korea Society for Simulation Conference
• /
• 2001.10a
• /
• pp.306-312
• /
• 2001

In this research, we are trying to develop a framework to evaluate the prevention program for Tsunami disaster based on the Multi-agent simulation model. Tsunami has arisen by the earthquake. It happened after flew minutes or few hours when it occurred. It is clear that Tsunami will come after earthquake and from seashore. If we prevent the damage by Tsunami, we should make people who is in the seashore and lived near the seaside escape from there. Moreover we must forecast the escape activity from Tsunami. Former research of this field, some researches try to forecast the escape activity as macro level. However, people who escape from Tsunami is differ from their physical ability and ability of information processing. It needs a more accuracy model to forecast the escape activity of them. Furthermore they make a decision step by step using the various information. Therefore escape activity from Tsunami will describe using an agent based model which can only treat the information processing of human being. In this paper, we develop the evacuation model from Tsunami disaster using the Multi agent based model. The purpose of this study is to analyze the human action pattern when Tsunami occurred, and to make an accurately assessment for damages by Tsunami. The Fujisawa city government is planning and operating the various prevention program far Tsunami. However nobody assess it, because they do not have any simulation models for Tsunami disaster. If they want to set an effective prevention program for Tsunami, they should have any kinds of simulation model. The results of this study are 1) To develop the Multi agent based evacuees escape activity model. 2) Assess the damage of Tsunami in Fujisawa-City.

• Archives of Plastic Surgery
• /
• v.48 no.5
• /
• pp.553-558
• /
• 2021

The diagnosis of the main complications resulting from lipoabdominoplasty has not yet been standardized. Infrared thermal imaging has been used to assess possible complications, such as necrosis and changes in micro- and macro-circulation, based on perforator mapping techniques, among others. The objective of this study was to present two clinical cases involving thermal imaging monitoring of the healing process of lipoabdominoplasty in the immediate postoperative evaluation and its preliminary results. Infrared thermography was performed 24 hours after the operation and on postoperative days 5, 25, and 27. In clinical case 1, it was found that the delta-R (∆T_R)-defined as the difference in minimum temperature between the highest and lowest points in the SA3 region (caution suction area) following the classification established by Matarasso-was 0.4℃ at 24 hours after surgery and decreased to 0.1℃ on a postoperative day 5. There were no complications in this case. In contrast, in clinical case 2, the ∆T_R was 1.7℃ at 24 hours after surgery (upon hospital discharge) and remained high, at 2.2℃, on postoperative day 5. A higher ∆T_R was found in the second patient, who developed necrosis of the surgical wound. The ∆T_R thermal index may be a new tool for predicting possible complications, complementing the clinical evaluation and therapeutic decision-making.