• The Journal of the Acoustical Society of Korea
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• v.38 no.3
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• pp.266-274
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• 2019

As can be seen in the statistics on domestic performance facilities, small or large scale of acoustic renovations seem to be unavoidable in many of those facilities due to its senility. However it is hard to find case studies which can be referred to for its acoustic renovation process. This study tried to provide a case study example of acoustic renovation for a high school auditorium which has many restrictions as a cultural heritage building. Requirements from the client and acoustic problems found through a field measurement of existing space motivated acoustic design solutions and alternatives which can improve the acoustics of the space. The whole process from the initial stage of diagnosing acoustic problems to the final stage of a post acoustic evaluation after the completion of construction was described. The result from the post acoustic evaluation suggested that reverberation characteristics of the space as well as definition and clarity have been greatly improved by applying acoustic design solutions and alternatives. However, loudness of sounds in the space didn't reach the aimed level, which is due to the limited capability of slat ceiling structure for providing strong early reflections.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.36 no.5
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• pp.83-91
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• 2020

Environmental conditions are known to impact human health and behavior, emotions such as pleasure, anxiety, and depression, and reduce stress. Interior design that elevates emotional comfort and satisfaction can help improve mental health and well-being. This study is a systematic review that analyzed previous empirical studies that explored the effect of interior design elements on the user's emotional response which is quantitatively evaluated by bio-signal and qualitatively evaluated through self-reported questionnaire surveys. This paper aims to derive the attributes of interior design and biometric indicators that affect the user's positive emotion through the synthesis of previous studies and to confirm the feasibility of measuring bio-signals as an objective evaluation tool for architectural design and as a quantitative research method. As a result of the review, the biometric data from EEG, fMRI, ECG, EMG, GSR, and eye-tracking were used to measure the participants' emotional responses, which were manifested as positive or negative depending on certain attributes of interior design such as the form, color, lighting, material and furniture. The attributes of interior design related to the positive emotional response were the curved shape, high ceiling, openness of space, and subdued tone colors. Standard lighting conditions and wooden spaces were related to stress reduction in terms of comfort and relaxation. The free arrangement of furniture was related to the user's positive emotions. On the other hand, consistent experimental protocols could not be found, and although the sample sizes of the studies were small, the studies have demonstrated the feasibility of the emotional response measurement by using the biometric data. Therefore this method can be a useful objective tool in the measurement of human-centric data in architectural design, and to develop the evidence-based design to induce positive emotions and minimize stress.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.3
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• pp.19-28
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• 2018

Key factors that ensure competitiveness of modular unit include consistent high quality and connection condition that ensures high structural performance while minimizing the overall scale of the on-site process. However, it is difficult to evaluate the structural performance of the connection of modular unit, and its structural analysis and design method can be different depending on the connection to its development, which affects the seismic performance of its final design. In particular, securing the seismic performance is the key to designing modular systems of mid-to-high-rise structure. In this paper, therefore, the seismic performance of the modular system with bracket-typed fully restrained moment connections according to stiffness and the shapes of various connection members was evaluated through experimental and analytical methods. To verify the seismic performance, a cyclic loading test of the connection joint of the proposed modular system was conducted. As a result of this study, theoretical values and experimental results were compared with the initial stiffness, hysteresis behavior and maximum bending moment of the modular system. Also, the connection joint was modeled, using the commercial program ANSYS, which was then followed by finite element analysis of the system. According to the results of the experiment, the maximum resisting force of the proposed connection exceeded the theoretical parameters, which indicated that a rigid joint structural performance could be secured. These results almost satisfied the criteria for connection bending strength of special moment frame listed on KBC2016.

• Journal of Advanced Navigation Technology
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• v.22 no.2
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• pp.111-122
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• 2018

At present, the ground transportation system is saturated in many countries including Korea. To overcome this problem, many researches of developing a roadable personal air vehicle (PAV) are being carried out to alleviate traffic congestion and to accomplish door-to-door mobility through three-dimensional traffic system. In this study, the thrust-to-weight ratio, the wing loading, and the power-to-weight ratio that are major design parameters for the sizing of roadable PAVs were calculated under the constraints of ground roll, climb rate, maximum cruise speed, service ceiling, stall speed. Also, in the sizing process, the study was conducted to determine the design point using the graphs of thrust-to-weight ratio, wing loading, power-to-weight ratio, and brake horse power for the mission profiles considering domestic environments and the FAR PART 23 which is the GA class aircraft certification standard.

• Imaging Science in Dentistry
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• v.51 no.2
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• pp.137-148
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• 2021

Purpose: This study aimed to assess the computer monitors used for analysis and interpretation of digital radiographs within the clinics of the Oral Health Centre of Western Australia. Materials and Methods: In total, 135 computer monitors(3 brands, 6 models) were assessed by analysing the same radiographic image of a combined 13-step aluminium step wedge and the Artinis CDDent 1.0^® (Artinis Medical Systems B.V.^®, Elst, the Netherlands) test object. The number of steps and cylindrical objects observed on each monitor was recorded along with the monitor's make, model, position relative to the researcher's eye level, and proximity to the nearest window. The number of window panels blocked by blinds, the outside weather conditions, and the number of ceiling lights over the surgical suite/cubicle were also recorded. MedCalc^® version 19.2.1 (MedCalc Software Ltd^®, Ostend, Belgium, https://www.medcalc.org; 2020) was used for statistical analyses(Kruskal-Wallis test and stepwise regression analysis). The level of significance was set at P<0.05. Results: Stepwise regression analysis showed that only the monitor brand and proximity of the monitor to a window had a significant impact on the monitor's performance (P<0.05). The Kruskal-Wallis test showed significant differences (P<0.05) in monitor performance for all variables investigated, except for the weather and the clinic in which the monitors were placed. Conclusion: The vast performance variation present between computer monitors implies the need for a review of monitor selection, calibration, and viewing conditions.

• Journal of the Korean Wood Science and Technology
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• v.30 no.3
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• pp.75-84
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• 2002

In order to find out impact insulation properties, various types of current radiant floor heating systems and light-framed floors that are used in light-framed residential buildings were evaluated for two types of impact sources at the same time. Sound Pressure Level (SPL) was different from each impact sources for those spectrum patterns and peaks. In case of light-framed floor framework, the excitation position and the assumed effective vibrating area have effects on sound pressure level but it is not considerable, and Normalized SPL was reduced for each frequency by increasing the bending rigidity of joist. The mortar layer in the radiant heating system had relatively high density and high impedance, therefore, it distributed much of the impact power when it was excited, and reduced the Normalized SPL considerably. Nevertheless, Increasing a thickness of mortar layer had little influence on SPL. Ceiling components reduced the sound pressure level about 5~25 dB for each frequency. Namely, it had excellent sound insulation properties in a range from 200 to 4,000 Hz frequency for both heavy and lightweight impact sources. Also, there was a somewhat regular sound insulation pattern for each center frequency. The resilient channel reduced the SPL about 2~11 dB, irrelevant to impact source. Consequently, current radiant floor heating systems which were established in light-framed residential buildings have quite good impact sound insulation properties for both impact sources.

• Explosives and Blasting
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• v.40 no.4
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• pp.1-14
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• 2022

To review the appropriateness of current regulations on the simple explosive storage facility, the effects of internal explosion on the structural stability of the standard storage facility were analyzed by means of both FEM analyses and field experiments. As a result, it was found that the explosion-proof performance of the existing storage structure was not sufficient for 15 kg of emulsion-type explosive. Thus, an alternative method of splitting explosives was tested by conducting sympathetic detonation experiments. This method worked properly as expected, and the proper amount of splitted explosive was determined according to the test results. In addition, a storage structure with open ceiling was found to be very effective because explosion pressure was released so rapidly that the damage of the facility could be reduced significantly. Hence, such a structural pattern was proposed as a new design scheme for simple explosive storage facility.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.4
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• pp.677-686
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• 2023

In this paper, we study the design and implementation of a smart home outing care system that recognizes the user's purpose of going out and delivers useful information that can help when going out. RSS service data of the Korea Meteorological Administration can be transmitted in real time using ESP8266, and a system that can provide weather information to users after analyzing the data using Arduino MEGA is implemented. Using App Inventor, you can pack the necessary items without forgetting, and you can change the settings according to the desired weather and purpose. The position of the microphone was placed outside to increase awareness by 12%, and the sensitivity of the pressure sensor was set to a maximum of 210 kΩ. If there is an obstacle between the doors, the doors open automatically. An ultrasonic sensor was placed on the ceiling of the drawer to recognize an object within the range of 0.5cm to 10cm to check the existence of an object, and a camera was installed to research a security reinforcement system.

• Physical Therapy Korea
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• v.30 no.1
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• pp.32-40
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• 2023

Background: Equating is a statistical procedure used to create a common measurement scale across two instruments. Item-level information should be taken into consideration so that scores can communicate interchangeably across the instruments. Objects: To investigate a common measurement scale across two health-related quality of life questionnaires (HRQOL) applied to various cancer survivors who underwent palliative care in healthcare institutions. Methods: A total of 139 cancer survivors who underwent palliative care were recruited from two rehabilitation hospitals and an oriental medicine hospital. Participants consisted of various cancer survivors who presented to the sites for palliative care. They were asked to fill out Korean versions of the World Health Organization Quality of Life (WHOQOL-BREF) and EuroQOL-5 dimension (EQ-5D) questionnaires following the palliative care. For the item level comparison, the Rasch rating scale model was used to investigate how participants regarded individual test items of two instruments in relation to item difficulty calibrations. Results: All items except the three items fit the Rasch model. One item (anxiety/depression) of the EQ-5D and two items (dependence on medical aids and negative feelings) of the WHOQOL-BREF are misfit. The WHOQOL-BREF targets the survivors well, while the EQ-5D is able to target the survivors with lower HRQOL levels with some ceiling effects. By inspecting the item difficulty calibrations of the two instruments, five items of the WHOQOL-BREF are selected as common items in relation to the EQ-5D. These five items are considered compatible with each other. Differential item functioning (DIF) analysis reveals that the healthcare item of the WHOQOL-BREF vs the self-care item of the EQ-5D exhibits significant DIF. Conclusion: Findings suggest that one paired item should be taken into consideration when equating the WHOQOL-BREF and the EQ-5D applied to cancer survivors who underwent palliative care.

• Nuclear Engineering and Technology
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• v.54 no.11
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• pp.4195-4208
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• 2022

In this study, operator habitability was numerically evaluated in the event of a fire at the main control bench board (MCB) in a reference main control room (MCR). It was investigated if evacuation variables including hot gas layer temperature (HGLT), heat flux (HF), and optical density (OD) at 1.8 m from the MCR floor exceed the reference evacuation criteria provided in NUREG/CR-6850. For a fire model validation, the simulation results of the reference MCR were compared with existing experimental results on the same reference MCR. In the simulation, various input parameters were applied to the MCB panel fire scenario: MCR height, peak heat release rate (HRR) of a panel, number of panels where fire propagation occurs, fire propagation time, door open/close conditions, and mechanical ventilation operation. A specialized-average HRR (SAHRR) concept was newly devised to comprehensively investigate how the various input parameters affect the operator's habitability. Peak values of the evacuation variables normalized by evacuation criteria of NUREG/CR-6850 were well-correlated as the power function of the SAHRR for the various input parameters. In addition, the evacuation time map was newly utilized to investigate how the evacuation time for different SAHRR was affected by changing the various input parameters. In the previous studies, it was found that the OD is the most dominant variable to determine the MCR evacuation time. In this study, however, the evacuation time map showed that the HF is the most dominant factor at the condition of without-mechanical ventilation for the MCR with a partially-open false ceiling, but the OD is the most dominant factor for all the other conditions. Therefore, the method using the SAHRR and the evacuation time map was very useful to effectively and comprehensively evaluate the operator habitability for the various input parameters in the event of MCB fires for the reference MCR.