• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.11a
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• pp.233-234
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• 2022

In Korea, various policies are implemented so that the socially disadvantaged (disabled, elderly, pregnant women, temporary disabled, etc.) can easily access individual facilities and areas. As the nation's interest in the socially disadvantaged increases, the need for BF certification is also emerging in buildings in private facilities. However, this system requires a lot of cost and time in the examination process, so if certification fails, social costs and time losses are high. To solve this problem, this paper presents a measurement plan for mixed reality devices using HoloLens, a mixed reality device hardware that can pre-check BF certification based on augmented reality, and Unity 3D, MRTK, a development tool.

• Journal of the Korea Safety Management & Science
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• v.12 no.2
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• pp.99-105
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• 2010

In this paper, the uAPSS(u-APartment Service System) that is based on location-aware technology is designed and implemented for a luxury apartment. On the real luxury apartment the developed system has been employed and tested to provide convenient and secure living for residents. It provides services such as emergency call, intelligent elevator operation, and hands-free door access based on the location of the residents with personal device as called smart tag. It can also be applied to other service areas such as the location-aware u-Service for hospitals, high-rising complex buildings, silver towns, etc.

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.422-423
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• 2019

In accordance with the Carbon-Free Island by 2030 policy of Jeju Special Self-Governing Province, renewable energy sources are increasing in Jejudo Island. Due to the intermittent output characteristics of wind turbines, one of the renewable energy sources, which can cause unbalanced system conditions between the demand load and the power generation of Jejudo Island. The Korea Power Exchange limits the output of wind turbines for stabilizing the Jeju power system. Therefore, this paper proposes a method to supply a limited output of Sangmyeong Wind Farm in Jeju Power system to Energy Storage System(ESS) and Water Electrolysis Device(WED). The voltage and frequency fluctuation of the Jeju power system is checked accordingly. The simulation results are performed using the PSCAD/EMTDC program.

• Journal of Power Electronics
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• v.14 no.2
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• pp.257-264
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• 2014

A novel converter-free AC LED driver that is highly resistant to the fluctuation of AC voltage is proposed in this study. By removing large passive components, such as the bulky capacitor and the large-value inductor, the integration of the driver circuit is enhanced while the driving current remains stable. The proposed circuit provides LED lamps with a driving current that can follow the sinusoid waveform to obtain a very high power factor (PF) and low total harmonic distortion (THD). The LED input current produced by this driving current is insensitive to fluctuations in the AC voltage. Users will thus not feel that LED lamps are flashing during the fluctuation. Experiment results indicate that the proposed system can obtain PF of 0.999 and THD as low as 3.3% for a five-string 6 W LED load under 220 V at 50 Hz.

• Aerospace Engineering and Technology
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• v.9 no.2
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• pp.168-175
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• 2010

During feeding oxidizer to the engine, vortices are occurred at lower dome of oxidizer tank inside by various working environments and external forces for liquid propellant feeding system of space launch vehicle. To eliminate the vortices or swirls Anti-Vortex Devices(AVD) shall be installed at inside lower oxidizer tank. Using the numerical analysis, we have confirmed the performance of AVD and analyzed the mass flow rate by feeding time and magnitudes of swirls on the free surface of oxidizer or exit surface according to the AVD number and length. Then we could derive the optimal design of the AVD number and length.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.7
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• pp.778-784
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• 2012

In comparison with some other light sources, LED has merits such as increased life expectancy, fast response, pollution free, and high energy efficiency. Lately, due to development of LED with high brightness and capacity, LED has widely used in many industrial fields such as automotive, aviation, display, transportation and special lighting applications. Since the high heat generation of LED chips can cause a reduction in lifetime, degradation of luminous efficiency, and variation of color temperature, studies have been carried out on the optimization of LED packaging and heat sinks. In this study, experiments on measuring the heat generation rate of LED and the cooling performance of a heat sink were carried for analyzing the thermal characteristics of LED lighting system in free convection. From the results, dimensionless correlation on the cooling performance of heat sink in natural convection was proposed with Nusselt number and Rayleigh number as a guideline for designing cooling device of LED lightings.

• Journal of Satellite, Information and Communications
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• v.12 no.1
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• pp.114-119
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• 2017

In this paper we present the search on HC-06 Bluetooth based driver module for emergency LED Multi-Directional Indicator. Nowadays, a growing trends in which electronic displays such as LED, LCD or plasma monitors are being installed in public places like bars, stores, entertainment areas, restaurants, lobbies, etc. In this paper, the study is curried out on efficiency of HC-06 Bluetooth module based controller driver that relates generally to the field of emergency signage management systems for displaying various indicator contents remotely on electronic displays in public and privates venues. It allows user smart devices interaction remotely with digital signage by providing content for displaying on at least one display in a venue. Depending on the emergency case, HC-06 Bluetooth based driver module proves the high efficiency as well as good performance of processing and communicating remotely the indicator based message that is displayed from a venue management control system by using smart devices. The system combines smart device that linked to HC-06 Bluetooth module with ATmega168/328 embedded micro controller which result by switching the displayer containing the digital signage indicator based message.

• Korean Journal of Artificial Intelligence
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• v.10 no.2
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• pp.1-6
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• 2022

In this paper, the research and development aim to strengthen the digital accessibility of the elderly by developing a kiosk incorporating AI voice recognition technology that can replace the promotional signage currently being installed and spread in the elderly and social welfare centers most frequently used by the digital underprivileged. It was intended to develop a converged system for the use of bulletin board functions, educational functions, and welfare center facilities, and to seek ways to increase the user's digital device experience through direct experience and education. Through interviews and surveys of senior citizens and social welfare centers, it was intended to collect problems and pain Points that the elderly currently experience in the process of using kiosks and apply them to the development process, and improve problems through pilot services. Through this study, it was confirmed that voice recognition technology is 2 to 6 times faster than keyboard input, so it is helpful for the elderly who are not familiar with device operation. However, it is necessary to improve the problem that there is a difference in the accuracy of the recognition rate according to the surrounding environment with noise. Through small efforts such as this study, we hope that the elderly will be a little free from digital alienation.

• Fire Science and Engineering
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• v.15 no.4
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• pp.49-56
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• 2001

There have been the current controversy over effectiveness of the pressurized smoke control systems, which are installed within escape shaft to provide 'smoke-free' access for escaping peoples. Therefore, many effective measures were given in this paper by means of the production of a design guide for various types of escape routes used in domestic buildings. The solutions were established on basis of both an investigating current door closing device application in existing facilities and global standardization for pressurized smoke control system, especially in British Standard. Finally, the design guidance for open door air velocity with introduction to three door protection clauses was presented on the basis of consideration of the safety and economical factor,

• Korean Journal of Optics and Photonics
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• v.4 no.1
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• pp.9-14
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• 1993

We chose Bessel beamu[$J_o(ar)}$)l in order to investigate image forming property of the optical system with combined filter of amplitude and phase(CFAP). This paper investigated numerically the influence of number of nodes of these beams on the PSF, encircled energy(E), transmission ratio(TR), gain((;) for an aberrated(1aberration-free) optical system. These results showed that the property of PSF differ considerably from the one of the existing amplitude filter and that Bessel beam has super compensating effect for an optical system with spherical aberration. Particularly, the Bessel beam has less the size of central spot than the radius of Airy disk, this result can therefore be applied to the fabrication of semiconductor device.