• Journal of the Korea Convergence Society
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• v.10 no.4
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• pp.147-151
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• 2019

Modern people spend most of their daily lives in their homes, schools, or workplaces, hospitals, shopping malls, subway stations, rooms, and parking lots. According to the survey, air quality management at the multi-use facility is less than 50% satisfied. In this study, a photocatalytic filtration system is developed by utilizing a broadband-to-active photocatalyst that utilizes a media photocatalyst filter that removes airborne germs from indoor air as well as indoor air quality and operates on visible light as well as ultraviolet light.

• Journal of the Semiconductor & Display Technology
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• v.21 no.4
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• pp.99-105
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• 2022

Public attention to the indoor environment of underground subway stations, which is a representative multi-use facility, has been increasing along with the increase in indoor activities. In underground stations, fine iron oxide, which affects the health of users, is generated because of the friction between wheels and rails. Among particulate pollutant reduction technologies, plants have been considered as a non-chemical air purification method, and their effects in reducing certain chemical species have been identified in previous studies. The present study aimed to derive the total quantitative and qualitative reduction effects of a bio-filter system comprising air purifying plants, installed in an underground subway station. The experiment proceeded in two ways. First, PM(particulate matter) reduction effect by vegetation biofilter was monitored with the IAQ(indoor air quality) station. In addition, chemical speciation analysis conducted on the samples collected from the experimental and control areas where plants and irrigation using SEM-EDS(scanning electron microscopy-energy dispersive X-ray spectroscopy). This study confirmed the effect of the vegetation bio-filter system in reducing the accumulation of particulate pollutants and transition and other metals that are harmful to the human body.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.11a
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• pp.96-97
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• 2018

Facilities used by senior citizens, infants, and disabled people have characteristics that make it difficult to escape on their own or require a lot of evacuation time. Therefore, to ensure safety in case of fire, clear measures for securing safety of facilities, fire response methods, and training are required in accordance with the regulations. In case of postnatal care center facilities, newborn babies and mothers reside 24 hours a day, and as they are located in high-rise and multi-use facilities, measures for fire safety are necessary, but the domestic manual lacks. Accordingly, a field survey for security of the manual revealed that the establishment of awareness and facilities on temporary waiting areas and smoke control, which are easy for evacuation and fire safety, was a problem.

• Nuclear Engineering and Technology
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• v.35 no.5
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• pp.426-441
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• 2003

A reactor inlet header break experiment, B9401, performed in the RD-14M multi channel test facility was analyzed using RELAP5/MOD3.2 and RELAP5/CANDU[1]. The RELAP5 has been developed for the use in the analysis of the transient behavior of the pressurized water reactor. A recent study showed that the RELAP5 could be feasible even for the simulation of the thermal hydraulic behavior of CANDU reactors. However, some deficiencies in the prediction of fuel sheath temperature and transient behavior in athe headers were identified in the RELAP5 assessments. The RELAP5/CANDU has been developing to resolve the deficiencies in the RELAP5 and to improve the predictability of the thermal-hydraulic behaviors of the CANDU reactors. In the RELAP5/CANDU, critical heat flux model, horizontal flow regime map, heat transfer model in horizontal channel, etc. were modified or added to the RELAP5/MOD3.2. This study aims to identify the applicability of both codes, in particular, in the multi-channel simulation of the CANDU reactors. The RELAP5/MOD3.2 and the RELAP5/CANDU analyses demonstrate the code's capability to predict reasonably the major phenomena occurred during the transient. The thermal-hydraulic behaviors of both codes are almost identical, however, the RELAP5/CANDU predicts better the heater sheath temperature than the RELAP5/MOD3.2. Pressure differences between headers govern the flow characteristics through the heated sections, particularly after the ECI. In determining header pressure, there are many uncertainties arisen from the complicated effects including steady state pressure distribution. Therefore, it would be concluded that further works are required to reduce these uncertainties, and consequently predict appropriately thermal-hydraulic behaviors in the reactor coolant system during LOCA analyses.

• Journal of Power Electronics
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• v.14 no.2
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• pp.271-281
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• 2014

Fluctuating wind conditions necessitate the use of a variable speed wind turbine (VSWT) with a AC/DC/AC converter scheme in order to harvest the maximum power from the wind and to decouple the synchronous generator voltage and frequency from the grid voltage and frequency. In this paper, a combination of a three phase diode bridge rectifier (DBR) and a modified topology of the diode clamped multilevel inverter (DCMLI) has been considered as an AC/DC/AC converter. A control strategy has been proposed for the DCMLI to achieve the objective of grid interface of a wind power system together with local load compensation. A novel fixed frequency current control method is proposed for the DCMLI based on the level shifted multi carrier PWM for achieving the required control objectives with equal and uniform switching frequency operation for better control and thermal management with the modified DCMLI. The condition of the controller gain is derived to ensure the operation of the DCMLI at the fixed frequency of the carrier. The converter current injected into the distribution grid is controlled in accordance with the wind power availability. In addition, load compensation is performed as an added facility in order to free the source currents being fed from the grid of harmonic distortion, unbalance and a low power factor even though the load may be unbalanced, non-linear and of a poor power factor. The results are validated using PSCAD/EMTDC simulation studies.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.9
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• pp.38-45
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• 2003

This research is concerned with the dynamic modeling of the multi-purpose satellite with deployable solar arrays equipped with strain energy hinges(SEH). To this end, we proposed the use of the equivalent torsional spring for the SEH and derived the equations of motion assuming that the satellite and solar arrays are being rigid. We also considered the effect of the support string for the ground experiment model, which has been observed as a critical factor affecting the deployment in the ground experiments. From the numerical simulation results, it is found that solar arrays are deployed in a similar pattern but the hub motions are different because of the support strings. It was concluded that the non-gravity deployment of the solar arrays can be approximately simulated by the ground experimental facility. The effects of the support string are also investigated by varying the length of the string. It was found that the current length of the string is adequate for the ground experiment. Ground experimental results will follow.

• Journal of the Korean housing association
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• v.24 no.6
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• pp.41-49
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• 2013

This study finds out the aged consumers' needs on the developing elderly friendly and sensitive bathtub. This bathtub focuses on enhancement of multi-senses and enhancement of health, safety & convenience during bath. The enhancing multi-senses would have four functions; therapy with color and aroma, the massage with micro water bubbles, the visual and auditory with TV & cinema, and the auditory with music and radio. Also, enhancing others of bathtub would have seven functions; emergency bell, blood-pressure check system for health condition, water temperature indicator, keeping water warm, reading a book in that, and controlling of house entrance door and a getting the phone during bath. The aged consumers' needs find throughout a questionnaire survey, and 497 data was analyzed. The main results are as follow. They consider a full bath behavior as a healthcare. They have an intention to purchase or use the elderly and friendly bathtub, and they prefer using it in common facilities to using it at home. They highly need health related function of bathtub, which are massage (64.4%), blood-pressure check system (55.1%) and aroma therapy (45.7%). The emergency bell (67.0%), keeping water warm (62.2%), and water temperature indicator (49.7%), related to safety & information function of bathtub, are needed. Also, they think tolerance for error and low physical effort in bathtub design alternative, opening door and inside sitting support, to be important.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.5
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• pp.85-90
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• 2015

Work environments within the firm with a concept of mobile office is growing divided into two sections. It's Wi-Fi FMC(Fixed Mobile Convergence) field Which are implemented in a telephone service available from existing fixed-line service in the center of the smart phones and the EMS(Enterprise Mobility Service) field to make people will be able to handle PC the center of the information system within an enterprise using a smart phone instead of terminal facility connects to a system in the workplace and external. This paper developed FMC controller to allow execution IMS(IP Multi-Media Subsystem) services to complement the issues of the FMC corporation, telephony service associated. The controller includes FMC automatic enrollment services, voice quality enhancement of the mobile phone, anywhere within the firm on his mobile phone calls can provide mobility and is also implemented FMC LCR function that use status information from mobile soft-phone within the IP-PBX.

• The Journal of Engineering Geology
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• v.28 no.2
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• pp.297-312
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• 2018

In order to assess the safety diagnosis and grouting reinforcement effect of old reservoir facility, local governments and public offices mainly use electrical resistivity survey. However, electrical resistivity survey is a qualitative evaluation that varies the resistivity value by various exploration conditions. It is also difficult to grasp the stiffness change directly related to the stability of reservoir, thus an electrical resistivity survey is not applicable to continuous stability monitoring after grouting. The purpose of this study is to investigate and validate the quantitative evaluation of reinforcement effect of reservoir with cement grouting through shear velocity (Vs), which is closely related to the stiffness (${\mu}$) of the ground. This study was carried out on two reservoir facilities. The reinforcement effect was evaluated by comparing the permeability test, standard penetration test, down-hole test and MASW(Multi-channel Analysis of Surface wave) survey before and after cement grouting. Shear wave velocity changes before and after grouting were analyzed by phase velocity difference and inversion analysis, respectively, and the reliability of the analytical results was evaluated by comparing with field test results. Shear wave velocity increases to 5~10% in case of the D levee, and 10~20% in the levee of H reservoir. These results are showed similar pattern to the field test results.

• Journal of the Korean Association of Geographic Information Studies
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• v.18 no.2
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• pp.59-74
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• 2015

The purpose of this study is to analyze reasonable green area ratios for mitigating urban heat island considering various land use types. Land uses of 5 types such as single residential, multi residential, commercial area, public facility, and industrial area were considered. Green areas were extracted from the tree attribution of land cover. Effect of urban heat island was analysed by the surface temperature of ASTER thermal infrared radiance scanned daytime and nighttime. Mitigation effect of green area at daytime was higher than nighttime. Surface temperature of green area was low in single residential at daytime. But the difference of surface temperature by each land use type was small. The effect of surface temperature mitigation of green area was lower in industrial area. The results of reasonable green area ratios for mitigating urban heat island indicate that surface temperature was the lowest with green area ratio of 40~50% in single residential, multi residential, and commercial area at daytime. Surface temperature of nighttime was not changed much by green area ratios. Therefore, the results of this study will be suggested in urban development planning to construct effectively green area for mitigating urban heat island.