• 한국음향학회:학술대회논문집
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• 한국음향학회 1994년도 FIFTH WESTERN PACIFIC REGIONAL ACOUSTICS CONFERENCE SEOUL KOREA
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• pp.785-790
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• 1994

The active noise control which regards the acoustic power as a target function to be minimized, is analyzed to test its feasibility of which simplifies the measurement system compared with the global acoustic energy based active noise control system. In fact, it is found that the acoustic power based active noise control strategy is equally likely as good as the global acoustic energy based active noise control method if the acoustic field of interest is diffusive or very low model density one. In the intermediate model density field, we also demonstrate that the power based control gives the similar results as the energy based control in terms of global sound energy reduction for the lightly damped enclosure which might be most important system in practical application. From all the theoretical and power based control strategy is dependent on the characteristics of the acoustic field to be controlled; i.e., the model density distribution, the degree of reverberation, and on the strength of modal interaction of the control source with the primary source; i.e., the location of control source.

• 한국인공지능학회지
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• 제9권2호
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• pp.15-21
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• 2021

This paper conducted a feasibility study by applying an Internet of Things and Artificial intelligence-based management system for the elderly living alone in an aging society. The number of single-person families over the age of 50 is expected to increase, and problems such as health, safety, and loneliness may occur due to aging. Therefore, by establishing an IoT-based care system for the elderly living alone, a stable service was developed through securing a rapid response system for the elderly living alone and automatically reporting 119. The participants of the demonstration test were subjects under the jurisdiction of the "Seongnam Senior Complex," and the data collection rate between the IoT sensor and the emergency safety gateway was high. During the demonstration period, as a result of evaluating the satisfaction of the IoT-based care system for the elderly living alone, 90 points were achieved. We are currently in the COVID-19 situation. Therefore, the number of elderly living alone is continuously increasing, and the number of people who cannot benefit from care services will continue to occur. Also, even if the COVID-19 situation is over, the epidemic will happen again. So the care system is essential. The elderly care system developed in this way will provide safety management services based on artificial intelligence-based activity pattern analysis, improving the quality of in-house safety services.

• Current Optics and Photonics
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• 제6권3호
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• pp.236-243
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• 2022

Monocrystalline silicon has excellent properties, but it is difficult to design and manufacture silicon-based mirrors that can meet engineering applications because of its hard and brittle properties. This paper used monocrystalline silicon as the main mirror material in an imaging system to carry out a feasibility study. The lightweight design of the mirror is completed by the method of center support and edge cutting. The support structure of the mirror was designed to meet the conditions of wide temperature applications. Isight software was used to optimize the feasibility sample, and the optimized results are that the root mean square error of the mirror surface is 3.6 nm, the rigid body displacement of the mirror is 2.1 ㎛, and the angular displacement is 2.5" under the conditions of a temperature of ∆20 ℃ and a gravity load of 1 g. The optimized result show that the silicon-based mirror developed in this paper can meet the requirements of engineering applications. This research on silicon-based mirrors can provide guidance for the application of other silicon-based mirrors.

• 국제학술발표논문집
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• The 7th International Conference on Construction Engineering and Project Management Summit Forum on Sustainable Construction and Management
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• pp.225-234
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• 2017

Mixed-reality technologies have proven to be valuable in many architecture, engineering and construction / facilities management (AEC/FM) applications. However, its potential of being adapted to facilitate hazard identification and risk communication in construction workplaces has yet to be fully explored. This paper makes an attempt to evaluate the feasibility of applying mixed-reality to enhancing safety risk communication in construction workplaces. Experiments have been designed in which Microsoft HoloLens^® together with a developed application will be used to intervene in the practice of jobsite risk communication. A cross-sectional survey will then be followed to examine the effectiveness and acceptability of this technology through analysis on data collected from participants in the construction industry. The preliminary results show that this emerging HoloLens^® technology, compared to the traditional communication methods (i.e., phone calls, walking up people and talk, and video conferencing), facilitates accurate, prompt safety communication on construction sites. Such findings signify the potential of applying mixed-reality to safety performance enhancement in the construction industry.

• Nuclear Engineering and Technology
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• 제56권5호
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• pp.1654-1666
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• 2024

The goal of this research is to propose a way to maximize small modular reactor (SMR) utilization to gain better market feasibility in support of carbon neutrality. For that purpose, a comprehensive tool was developed, combining off-design thermohydraulic models, economic objective models (levelized cost of electricity, annual profit), non-economic models (saved CO2), a parameter input sampling method (Latin hypercube sampling, LHS), and a multi-objective evolutionary algorithm (Non-dominated Sorting Algorithm-2, NSGA2 method) for optimizing a SMR-combined heat and power cycle (CHP) system design. Considering multiple objectives, it was shown that NSGA2+LHS method can find better optimal solution sets with similar computational costs compared to a conventional weighted sum (WS) method. Out of multiple multi-objective optimal design configurations for a 105 MWe design generation rating, a chosen reference SMR-CHP system resulted in its levelized cost of electricity (LCOE) below $60/MWh for various heat prices, showing economic competitiveness for energy market conditions similar to South Korea. Examined economic feasibility may vary significantly based on CHP heat prices, and extensive consideration of the regional heat market may be required for SMR-CHP regional optimization. Nonetheless, with reasonable heat market prices (e.g. district heating prices comparable to those in Europe and Korea), SMR can still become highly competitive in the energy market if coupled with a CHP system.

• 한국지열·수열에너지학회논문집
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• 제20권2호
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• pp.24-36
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• 2024

This study analyzed the feasibility of the air source heat pump in residential buildings based on operational performance and carbon emissions. The operational performance and carbon emissions were compared between a gas boiler and an air source heat pump by calculating the annual heating and hot water load based on the 21A and 36A models for actual residential buildings. For the operational performance of the air source heat pump, the lowest (2.3) and highest COP (5.9) were attained during the winter and summer seasons, respectively. The carbon emissions depend on the amount of energy consumed during operations. An air source heat pump consumed 65.10% and 65.4% less energy per year in the 21A and 36A models, respectively compared to the existing gas boiler. Consequently, for air source heat pump carbon emissions were also reduced by 13.3% and 15.1% per year for the 21A and 36A models, respectively. It shows the effectiveness of applying an air source heat pump compared to an existing gas boiler.

• PNF and Movement
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• 제16권1호
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• pp.67-73
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• 2018

Purpose: Smartphones, which are widely used worldwide to detect acceleration and position, have been used in the area of rehabilitation medicine in recent clinical research studies and tests. The aim of the present study was to determine the feasibility of using a smartphone application based on center of movement (COM) displacement to measure gait parameters in stroke patients in the clinical field of rehabilitation medicine. Methods: The study consisted of 30 stroke patients. The COM was measured using a smartphone application, Gait Analysis Pro, during a 6-m walk. Each patient performed three 6-m walking trials, and the smartphone application measured gait duration, gait speed, step length, cadence, and vertical and lateral displacement of the COM. The Kolmogorov-Smirnov test was conducted to determine the normality in gait parameters, and a repeated one-way analysis of variance (ANOVA) was performed to determine the consistency among the three trials. A p value of 0.05 was considered statistically significant in all the tests. Results: In all the measured parameters, the smartphone application showed a normal distribution, as shown by the results of the Kolmogorov-Smirnov test. There were no significant differences among the three repetitive walking trials. Conclusion: These results suggest that the smartphone application can be used for evaluating gait in stroke patients, as well as in healthy adults. However, prior to using the smartphone application in the clinical field, further research involving three-dimensional gait analysis is needed to enhance the confidence level of the findings.

• 한국통신학회논문지
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• 제36권8B호
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• pp.921-928
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• 2011

최근 인터넷 사용자의 증가와 다양한 인터넷 기반 응용프로그램의 증가로 네트워크 트래픽이 급증하고 있다. 효율적인 네트워크 트래픽 관리를 위해 기존의 많은 연구들 에서 다양한 분류 알고리즘을 제시하였고, 대부분의 제안된 방법들은 응용 단위로 트래픽을 분류하며 분류의 정확성을 높이는데 초점을 두고 있다. 하지만 트래픽 제어의 관점에서 보았을 때 응용단위의 트래픽 분류는 응용의 기능별 제어의 기회를 제공하지 못하고 네트워크 사용자가 각 응용의 어떤 기능을 사용하는지를 파악하지 못하게 되는 문제점을 가지고 있다 본 논문에서는 이러한 문제점들을 해결 하기 위해 NateOn, MSN, GoogleTalk의 인터넷 메신저 응용에 대하여 기능 오토마타를 설계하고 이를 통해 메신저 응용의 기능별 트래픽 분류를 위한 방법론을 제시한다.

• 전자통신동향분석
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• 제35권1호
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• pp.12-24
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• 2020

To keep pace with other powerful nations in this era of the era of digitalization and to emerge stronger in the world, the defense forces of South Korea aim to innovate and prepare themselves for digital battlefields of possible wars in the future. The resources in the defense sector, which is the core of defense intelligence, is based on an intelligent mission collaboration tactical network system via cyber, command, control, communication, and computer (C4), and military and non-human weapons. Defense intelligence depends on the degree of the convergence of advanced Information and communication technologies (ICTs). Considering this aspect of defense intelligence, We plan to determine the application status of defense blockchain technology and examine the feasibility of applying blockchain technology and the core of applied technology. Generally, a key feature of blockchain technology is its data integrity in untrusted environments. There are various types of core technologies for the blockchain depending on the target areas of application in the defense sector, and it is also essential to derive new application strategies for core technologies that are applied in combination with other ICT technologies. We plan to demonstrate new defense ICT converged technologies (DNAB2: Data, Network, AI, BigData, Blockchain) and DNAB2-As-Services in the defense strategy.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(1)
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• pp.430-433
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• 2003

IGBTS are widely used for the industrial inverters in the mid power range at low voltage (440V$\~$660V) application. Advantageous features of the device are simple gate drive and high speed switching capability. Due to these advantages the application of IGBTS is enlarging into the high power application. However, to increase the power handling capacity at lower input voltage level, the current rating in each bridge arm must be enlarged. Therefore the parallel operation of IGBT devices is essentially needed. This paper describes the feasible parallel structures of the power circuit for the mid & the high power inverters and introduces the important design condition for the parallel operation of IGBT devices. To verify feasibility of the IGBT parallel operation, the feature of several IGBT devices (EUPEC, SEMIKRON's IGBT) are investigated and the power stacks are implemented and tested with these devices. The experimental results show the good characteristics for the parallel operation of IGBTS.