• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.12 no.2
• /
• pp.120-130
• /
• 2000

A flow uniformity in a duct cooler of duct system of FGD(Flue Gas Desulfurization) linking a reheater and a absorber has been investigated in the present study. For this purpose, the flow characteristics according to the geometry of a vertical and horizontal vane in a curved duct of the duct system has been examined with the aid of a numerical simulation. The results indicate that the vertical vane with a little deflection toward a recirculation region makes the flow distribution in the duct cooler more uniform than that without deflection, and horizontal vane does not effect the change of the flow distribution for an angle of inclination. The mean flow uniform factor shows its maximum for duct system without the vane(case NP) and its minimum for the vertical vane with a little deflection(case P-0.8-0) .

• Journal of the Korean Solar Energy Society
• /
• v.30 no.6
• /
• pp.95-101
• /
• 2010

This paper presents performance estimation approach of grid-connected photovoltaic(PV) system to predict energy yield from irradiance to PV system using normalized yield model for changing meteorological conditions. The accuracy and validity of proposed performance estimation method is identified by compared measured with estimated yield using monitored data. These results will indicate that it is useful to estimate various loss factors causing the system performance obstruction and enhance the lifetime yield of PV system.

• ETRI Journal
• /
• v.31 no.2
• /
• pp.105-110
• /
• 2009

In this paper, we propose a curved projection integral imaging system to improve the horizontal and vertical viewing angles. The proposed system can be easily implemented by additional use of a large-aperture convex lens in conventional projection integral imaging. To obtain the simultaneous display of 3D images through real and virtual image fields, we propose a computer-generated pickup method based on ray optics and elemental images, which are synthesized for the proposed system. To show the feasibility of the proposed system, preliminary experiments are carried out. Experimental results indicate that our system improves the viewing angle and displays 3D images simultaneously in real and virtual image fields.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.48 no.5
• /
• pp.502-507
• /
• 1999

An improved, accurate and reliable high-voltage measuring system utilizing a bushing-type capacitor is proposed in this study. This system measures voltages and phase angles of three-phase 22.9 kV power distribution lines and provides enough current to charge a battery for a motor-driven load switch and to operate the measuring and communication circuits for the distribution automation. For reliability, epoxy resin was used as the dielectric material of the bushing-type capacitor since the dielectric strength of epoxy resin is very stable over the wide range of temperature. Capacitances were investigated and found to be stable over the wide range of temperature and applied voltage, and the results indicate that the proposed measurement system is very reliable.

• Proceedings of the KIEE Conference
• /
• 2003.07d
• /
• pp.2055-2057
• /
• 2003

This paper describes the results of RBD(Reliability Block Diagram) analysis of control rod control system, which is being developed as part of KNICS project. The results of RBD indicate unavailability of control cabinet for control rod control system. A purpose of RBB is to evaluate unavailability of control cabinet, identify the design drawbacks of control cabinet, and propose design improvement to a designer to help design the more reliable control rod control system. This RBD defines the logical interaction of failure within a system.

• Proceedings of the SAREK Conference
• /
• 2006.06a
• /
• pp.429-435
• /
• 2006

In this study multi-zone modeling program CONTAM 2.4 which is developed by NIST is used for modeling the air disinfection system which is consist of dilution, filtration, ultra violet germicidal irradiation (UVGI) for removing the indoor microorganism such as bacteria and fungus. Developed models those protect occupants against indoor microorganism generated in our daily life are enable to use for immune building simulation tool. Also, results indicate that those models are enable to compute the real situation that is almost impossible of carrying out experiment and identify the disinfection rate with highly reliance. Results also suggest that engineers will use these models as a design tool for the immune building system.

• Journal of Integrative Natural Science
• /
• v.14 no.3
• /
• pp.95-98
• /
• 2021

By far, studies on the effect of oral administration of peppermint essential oil on blood pressure are not consistent, increasing or decreasing. And the effect of inhalation of peppermint essential oil on blood pressure was not reported. This study was designed to clarify the effect of peppermint essential oil inhalation on the blood pressure and autonomic nervous system. Blood pressure and heart rate variability (HRV) as an indicator of autonomic nervous system activity were measured. The systolic and diastolic blood pressure was not changed significantly by inhalation of peppermint essential oil. Standard deviation of normal to normal (SDNN), a parameter of total activity of autonomic nervous system also was not changed significantly. High frequency (HF) power level, an indicator of parasympathetic nervous system activity was not changed by peppermint. These results indicate that action mechanism of peppermint essential oil on blood pressure is different by the method of administration, oral or inhalation.

• International Journal of Computer Science & Network Security
• /
• v.23 no.2
• /
• pp.164-172
• /
• 2023

Sharing power data between electrical power grids is crucial in energy management. The multi-agent approach has been applied in various applications to improve the development of complex systems by making them both independent and collaborative. The smart grid is one of the most intricate systems that requires a higher level of independence, reliability, protection, and adaptability to user requests. In this paper, a multi-agent system is utilized to share knowledge and tackle challenges in smart grids. The shared information is used to make decisions that aid in power distribution management within the grid and with other networks. The proposed multi-agent mechanism improves the reliability of the power system by providing the necessary information at critical times. The results indicate that the multi-agent system operates efficiently and promptly, making it a highly promising candidate for smart grid management.

• Journal of the Korean Society for Aviation and Aeronautics
• /
• v.30 no.4
• /
• pp.1-8
• /
• 2022

In this study, we propose trajectory-based arrival management using CDO (Continuos Descent Operations). The operational procedures with TBO (Trajectory-Based Operations) concept were established to allow aircraft and ground system to share the trajectories with each other in real time. The proposed operational concept was validated in the air traffic control simulation environment, which consists of controller working position, pseudo pilot system, air traffic generation system, and controllers' decision support system for arrival management using CDO. Simulation results compared with actual flight data indicate that proposed concept could improve the efficiency of traffic flow management in terms of total descending time and fuel consumption. And it was confirmed that if there is a system that can share and utilize the synchronized trajectory, it can be helpful to control arrival aircraft and apply CDO concept.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.17 no.2
• /
• pp.37-45
• /
• 2021

In this study, we want to analyze the difference in cost structure for the LAN audience system, which emerged as an alternative to the existing audience system due to the influence of Covid-19, and to analyze the utilization of the LAN audience system. To this end, the incremental cost difference between the existing audience system and the LAN audience system in the production of the broadcast program was compared and analyzed through the broadcasting production case by the actually performed LAN audience system. According to the research, the existing audience system has a linear cost structure that increases with the number of audience participants, while the LAN audience system has a calculated cost structure that gradually increases with the range of audience participants. These findings indicate that the LAN-line audience system costs more than the audience system, but the total cost is lower than the audience system for a certain number of people or more. This is a supplement to the existing audience system, which could not attract more audiences due to the lack of production costs, suggesting that the online audience system plays a role in supplementing the open broadcasting production system.