• Journal of Electrical Engineering and Technology
• /
• v.3 no.2
• /
• pp.184-191
• /
• 2008

Electrical endurance is the critical characteristic of Magnetic contactors(MCs), which are widely used in such power equipment as elevators, cranes, and factory control rooms in order to close and open control circuits. Testing time, however, is not short in typical cases in which some method of reducing the testing period is required. This study shows the method of determining the stress level of electrical ALT(Accelerated Life Test) through optical temperature sensor and the relationship between 0.05 s and 0.1 s for on-time. The tool used for analyzing the test result is MINITAB. I will propose the method of determining the optimized stress level through optical temperature sensor, which will contribute to minimize the testing time and development period and also raise the product reliability.

• Journal of Electrical Engineering and Technology
• /
• v.2 no.2
• /
• pp.188-193
• /
• 2007

Magnetic contactors (MCs) are widely used in industrial equipment such as elevators, cranes and factory control rooms in order to close and open the control circuits. The reliability of MCs mainly depend on mechanical durability and international standards such as IEC 60947-4-1, which stipulates the testing method for MCs. Testing time, however, is so long in usual cases that a method of reducing testing time is required. Therefore, a temperature and voltage-accelerated life testing (ALT) method has been developed to reduce the testing time in this work. The accelerated life test data are analyzed and acceleration factors (AFs) are provided.

• Journal of Urban Science
• /
• v.9 no.2
• /
• pp.13-20
• /
• 2020

The Recently, several countries have been affected by respiratory diseases, resulting in renewed research interest in their prevention and control. One such example was the 2015 outbreak of Middle East Respiratory Syndrome (MERS) in South Korea and COVID-19. In this study, we performed experiments and simulations based on concentration decay using CO2 as the tracer gas to elucidate the pollutant-removal efficiency for different inlet and exhaust locations and outdoor air-supply ratios. The wall inlet exhibited a higher pollutant-removal efficiency, owing to the upward movement of the air from the lower zone to the upper one. In conclusion, it is recommended that a total air-conditioning plan for isolation rooms be established as well as efficient system operation for pollutant removal and air-flow control to prevent the transmission of infections from the patients to others.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.25 no.2
• /
• pp.202-210
• /
• 2015

Objectives: The purpose of this study was to examine clean room(C/R) structure, air conditioning and contamination control systems and to provide basic information for identifying a correlation between the semiconductor work environment and workers' disease. Methods: This study was conducted at 200 mm and 300 mm semiconductor wafer fabrication facilities. The C/R structure and air conditioning method were investigated using basic engineering data from documentation for C/R construction. Furthermore, contamination parameters such as airborne particles, temperature, humidity, acids, ammonia, organic compounds, and vibration in the C/R were based on the International Technology Roadmap for Semiconductors(ITRS). The properties of contamination control systems and the current status of monitoring of various contaminants in the C/R were investigated. Results: 200 mm and 300 mm wafer fabrication facilities were divided into fab(C/R) and sub fab(Plenum), and fab, clean sub fab and facility sub fab, respectively. Fresh air(FA) is supplied in the plenum or clean sub fab by the outdoor air handling unit system which purifies outdoor air. FA supply or contaminated indoor air ventilation rates in the 200 mm and 300 mm wafer fabrication facilities are approximately 10-25%. Furthermore, semiconductor clean rooms strictly controlled airborne particles(${\leq}1,000{\sharp}/ft^3$), temperature($23{\pm}0.5^{\circ}C$), humidity($45{\pm}5%$), air velocity(0.4 m/s), air change(60-80 cycles/hr), vibration(${\leq}1cm/s^2$), and differential pressure(atmospheric pressure$+1.0-2.5mmH_2O$) through air handling and contamination control systems. In addition, acids, alkali and ozone are managed at less than internal criteria by chemical filters. Conclusions: Semiconductor clean rooms can be a pleasant environment for workers as well as semiconductor devices. However, based on the precautionary principle, it may be necessary to continuously improve semiconductor processes and the work environment.

• Korean Institute of Interior Design Journal
• /
• v.16 no.5
• /
• pp.81-88
• /
• 2007

Energy consumption has been increased world widely, and the energy retain is one of the most important economic alternatives. These tendencies expand the nuclear power plants not only quantitatively but also qualitatively. Despite of the increasing construction of nuclear power plants and related facilities, every system in main control room(MCR) has been designed and administered solely based on the safety-first principles because of the specificity of nuclear industry. However, recent main control rooms started with the concept that the operators' performance could be optimized though the organic interrelation between human, machine, and environments. Now, it has been recognised in the scope of Ergonomics and Space Design which acknowledge our living spaces as Man-Environment Interface and this change connotes the MCR spaces should be special spaces rather than ordinary spaces. This research investigated domestic and foreign nuclear power plants' MCRs to suggest basic alternatives which can be applied to future MCR. With the review of characteristics of MCR, an integration of interior design, lighting and Ergonomics was explored and classified as types. Futhermore, the classification of environmental characteristics within the relationships between human, machine, and environments was developed through the case analysis of nuclear power plants. The results of this study will provide a basis of space design for system environments that the high level of safety and function are extremely important.

• Child Health Nursing Research
• /
• v.7 no.4
• /
• pp.519-529
• /
• 2001

Recurrent abdominal pain(RAP) occurs in 8-10％ of elementary school children. It is suspected that functional causes are about 90％ and organic causes about 10％ for the recurrent abdominal pain. RAP is treated by antispasmodics or analgesics or antidiarrheal drugs in school health rooms. The purpose of this study was to verify the effect of Koryo-Hand-Acupuncture on recurrent abdominal pain of children. The duration of this study was from April to July, 2001. The subjects were the grade 4th-6th elementary students complaining recurrent abdominal pain. Total subjects were 46 cases; 23 cases of which were placed in experimental and the others in control group. The results of this study were as follows; 1. Numeric-pain-intensity of experimental group received Koryo-Hand-Acupuncture was decreased more than that of control group received mock Koryo-Hand-Acupuncture significantly. 2. Probed current in stomach corresponding point (A12) of experimental received Koryo-Hand-Acupuncture was decreased more than that of control group received mock Koryo-Hand-Acupuncture significantly. 3. Medication requirement rate of experimental group received Koryo-Hand-Acupuncture was decreased more than that of control group received mock Koryo-Hand-Acupuncture significantly. The following suggestions with the results of the study would be made like these; 1. Stimulation implement of Koryo-Hand- Acupuncture should be used independently and each effect should be investigated. 2. With repeated studies for various signs and diseases, the effect of Koryo-Hand- Acupuncture must be verified.

• The Journal of the Acoustical Society of Korea
• /
• v.37 no.5
• /
• pp.331-337
• /
• 2018

In this paper, we apply the NR (Noise Rating) to the evaluation of the residual noise of the window type ANC (Active Noise Control) and study the active noise controller for minimizing the NR value in rooms. We proposed a shape of a noise shaping filter of the Filtered-E LMS (Least Mean Square) algorithm that reduces the NR value within the effective operating frequency band of the ANC. The usefulness of the proposed scheme is verified by simulation and showed that the NR value of the residual noise is lower than the filters used in the conventional psychoacoustic ANC.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.22 no.2
• /
• pp.103-114
• /
• 2012

Nowadays membrane material is widely used for large indoor spaces and long spaces such as traditional market. Thermal insulation and sound field control performance is considered as a main properties for design of such buildings. In this paper sound absorption and thermal insulation properties of membrane material was investigated. Firstly, normal incidence sound absorption coefficient of 10 kinds of glass wool textiles showed that sound absorption coefficient was increased in proportion of thickness and surface density of textile. Sound absorption coefficient of 4 kinds of sound absorptive inner membrane with outer membrane was tested in the reverberation chamber. Sound absorption coefficient of mid frequency range was about 0.4 ~ 0.6. Also, sound absorption coefficient was changed by the air space behind the membrane material. Secondly, sound field control performance was investigated using mock-up space. By the installation of sound absorption membrane material, reverberation time was decreased and speech intelligibility was increased. Finally, thermal resistance and room temperature in two kinds of mock-up rooms were tested, simultaneously. Results of thermal properties showed thermal insulation properties ware increased by adding inner membrane material underneath the outer membrane.

• Nuclear Engineering and Technology
• /
• v.51 no.6
• /
• pp.1554-1560
• /
• 2019

Development of digital main control rooms (MCRs) has greatly changed operating environments by altering operator tasks, and thus the unique characteristics of digital MCRs should be considered in terms of human reliability analysis. Digital MCR tasks can be divided into primary tasks that directly supply control input to the plant equipment, and secondary tasks that include interface management conducted via soft controls (SCs). Operator performance regarding these secondary tasks must be evaluated since such tasks did not exist in previous analog systems. In this paper, we analyzed SC-related tasks based on simulation data, and classified the error modes of the SCs following analysis of all operational tasks. Then, we defined the factors to be considered in human reliability analysis methods regarding the SCs; such factors are mainly related to interface management and computerized operator support systems. As these support systems function to reduce the number of secondary tasks required for SC, we conducted an assessment to evaluate the efficiency of one such support system. The results of this study may facilitate the development of training programs as well as help to optimize interface design to better reflect the interface management task characteristics of digitalized MCRs.

• Journal of Home Health Care Nursing
• /
• v.9 no.1
• /
• pp.5-13
• /
• 2002

This study was conducted to assess need for education on the infection control by examining the knowledge on infection control in home care of the home care trainees who had completed an infection control course. Using 64 items questionnaire. home care trainees of eight home care education institutions who took classes related with infection control. The level of knowledge evaluated subjectively was 4.24point (full mark: 5 point). The correct answer rates for handwashing and gloving. cleaning patients' rooms. preventing sharp injury, preventing exposure to potential infectious agents, home care bag technique were 84.5% 86.4% 70.7% 65.3% 76.2% representatively. For the knowledge on the infection control principles to prevent catheter related infection, indwelling catheter related infection, tracheal tube related pneumonia. L-tube related infection, oxygen therapy related infection. and wound infection were 62.8% 27.8% 39.1% 87.8% 76.5% 80.5% representatively. The correct answer rates varied depending upon the educational institutes (p< = .0001), educational levels (p= .001), workplaces (p<.0001), and the experience of infection control education (p= .001). Considering these results. a standardized curriculum must be developed and implemented after analyzing the existing infection control curricula of the home care education institutes. and guide books for infection control in home care should be developed and distributed. In addition. continuous infection control education be provided to the home care nurses through reeducation so they can acquire new knowledge needed for carrying out infection control activities effectively.