• KEPCO Journal on Electric Power and Energy
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• 제7권2호
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• pp.249-254
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• 2021

As the spreading speed of electric vehicles increases rapidly, those are expected to be able to use them as flexible resources in the power system beyond the concern for the supply of its charging power. Especially when the Renewable Energy sources (RES) which have no intrinsic control capability have replaced the synchronous generators more and more, the power system needs to secure the additional frequency control resources to ensure its stability. However, the feasibility of using electric vehicles as the frequency control resources should be analyzed from the perspective of the power system operation and it requires the existing simulation frameworks for the power system. Therefore, this paper proposes the grid connected modeling of the primary frequency control provided by electric vehicles which can be integrated into the existing power system model. In addition, the proposed model is implemented considering technical performances constrained by the characteristics of the Vehicle-Grid Integration (VGI) system so that the simulation results can be accepted by the power utilities operating the power system conservatively.

• 대한청각학회지
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• 제24권1호
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• pp.1-9
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• 2020

Auditory scene analysis is defined as a listener's ability to segregate a meaningful message from meaningless background noise in a listening environment. To gain better understanding of auditory perception in terms of message integration and segregation ability among concurrent signals, we aimed to systematically review the size of auditory scenes among individuals. A total of seven electronic databases were searched from 2000 to the present with related key terms. Using our inclusion criteria, 4,507 articles were classified according to four sequential steps-identification, screening, eligibility, included. Following study selection, the quality of four included articles was evaluated using the CAMARADES checklist. In general, studies concluded that the size of auditory scene increased as the number of sound sources increased; however, when the number of sources was five or higher, the listener's auditory scene analysis reached its maximum capability. Unfortunately, the score of study quality was not determined to be very high, and the number of articles used to calculate mean effect size and statistical significance was insufficient to draw significant conclusions. We suggest that study design and materials that consider realistic listening environments should be used in further studies to deep understand the nature of auditory scene analysis within various groups.

• Journal of Audiology & Otology
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• 제24권1호
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• pp.1-9
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• 2020

Auditory scene analysis is defined as a listener's ability to segregate a meaningful message from meaningless background noise in a listening environment. To gain better understanding of auditory perception in terms of message integration and segregation ability among concurrent signals, we aimed to systematically review the size of auditory scenes among individuals. A total of seven electronic databases were searched from 2000 to the present with related key terms. Using our inclusion criteria, 4,507 articles were classified according to four sequential steps-identification, screening, eligibility, included. Following study selection, the quality of four included articles was evaluated using the CAMARADES checklist. In general, studies concluded that the size of auditory scene increased as the number of sound sources increased; however, when the number of sources was five or higher, the listener's auditory scene analysis reached its maximum capability. Unfortunately, the score of study quality was not determined to be very high, and the number of articles used to calculate mean effect size and statistical significance was insufficient to draw significant conclusions. We suggest that study design and materials that consider realistic listening environments should be used in further studies to deep understand the nature of auditory scene analysis within various groups.

• Smart Structures and Systems
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• 제29권4호
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• pp.561-576
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• 2022

Heritage timber structures represent the history and culture of a nation. These structures have been inherited from previous generations; however, they inevitably exhibit deterioration over time, potentially leading to structural deficiencies. Structural Health Monitoring (SHM) offers the potential to assess operational anomalies, deterioration, and damage through processing and analysis of data collected from transducers and sensors mounted on the structure. This paper reports on the design and implementation of a long-term SHM system on the Feiyun Wooden Pavilion in China, a three-story timber building built more than 500 years ago. The principles and features of the design and implementation of SHM systems for heritage timber buildings are systematically discussed. In total, 104 sensors of 6 different types are deployed on the structure to monitor the environmental effects and structural responses, including air temperature and humidity, wind speed and direction, structural temperatures, strain, inclination, and acceleration. In addition, integrated data acquisition and transmission subsystem using a newly developed software platform are implemented. Selected preliminary statistical and correlation analysis using one year of monitoring data are presented to demonstrate the condition assessment capability of the system based on the monitoring data.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2009년도 춘계학술발표대회
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• pp.456-458
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• 2009

소프트웨어의 크기가 커지고 복잡도가 증가함에 따라 소프트웨어 품질의 중요성은 점점 증대되고 있다. 소프트웨어의 품질 향상을 위해 소프트웨어 개발 조직은 테스트와 동료검토와 같이 제품 품질 향상을 위한 노력과 CMMI(Capability Maturity Model Integration), 소프트웨어프로세스 품질인증 기준과 같은 프로세스 품질 향상 노력을 하고 있다. 그러나 이러한 소프트웨어 분야의 품질 관리의 노력과 효과에 소요되는 품질비용에 대한 연구는 제조업이나 건설업 등 타 분야에 비해 부족한 실정이다. 본 연구에서는 소프트웨어 프로세스 개선을 위한 모델인 CMMI의 성숙도 레벨에 기반하여, K사의 품질비용관리 방안 적용 결과를 바탕으로 CMMI 성숙도 각 레벨마다 소프트웨어 개발 조직이 품질비용을 관리를 위한 목적과 활동으로 정의된 품질비용 관리 모델의 개발을 연구하였다.

• Smart Structures and Systems
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• 제32권3호
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• pp.179-193
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• 2023

This study explores an alternative to the existing centralized process for data anomaly detection in modern Internet of Things (IoT)-based structural health monitoring (SHM) systems. An edge intelligence framework is proposed for the early detection and classification of various data anomalies facilitating quality enhancement of acquired data before transmitting to a central system. State-of-the-art deep neural network pruning techniques are investigated and compared aiming to significantly reduce the network size so that it can run efficiently on resource-constrained edge devices such as wireless smart sensors. Further, depthwise separable convolution (DSC) is invoked, the integration of which with advanced structural pruning methods exhibited superior compression capability. Last but not least, quantization-aware training (QAT) is adopted for faster processing and lower memory and power consumption. The proposed edge intelligence framework will eventually lead to reduced network overload and latency. This will enable intelligent self-adaptation strategies to be employed to timely deal with a faulty sensor, minimizing the wasteful use of power, memory, and other resources in wireless smart sensors, increasing efficiency, and reducing maintenance costs for modern smart SHM systems. This study presents a theoretical foundation for the proposed framework, the validation of which through actual field trials is a scope for future work.

• 시스템엔지니어링학술지
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• 제20권spc1호
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• pp.1-11
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• 2024

Today, the importance of test and evaluation of defense systems is increasing day by day. In performing efficient defense systems test works, process improvement based on quantitative management is essential. The purpose of this paper is to present the results of process improvement for the defense systems test works of the test organization based on quantitative management activities. As a methodology to confirm process improvement performance, the 'MPM(Managing Performance and Measurement)' practice area of the CMMI model was applied. The quantitative management model for defense systems test works was developed so that it could be practically applied not only to the entire test organization but also to the organization at the department level that actually performs the test work. Finally, the application cases of the quantitative management model for defense system test works and the results of process improvement were described.

• Nuclear Engineering and Technology
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• 제56권3호
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• pp.1037-1051
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• 2024

This paper presents the construction results and design of the UNIST Reactor Innovation platform for small modular reactors as a versatile testbed for exploring innovative technologies. The platform uses simulant fluids to simulate the thermal-hydraulic behavior of a reference small modular reactor design, allowing for cost-effective design modifications. Scaling analysis results for single and two-phase natural circulation flows are outlined based on the three-level scaling methodology. The platform's capability to simulate natural circulation behavior was validated through performance calculations using the 1-D system thermal-hydraulic code-based calculation. The strategies for evaluating cutting-edge technologies, such as the integration of a solid oxide electrolysis cell for hydrogen production into a small modular reactor, are presented. To overcome experimental limitations, the hardware-in-the-loop technique is proposed as an alternative, enabling real-time simulation of physical phenomena that cannot be implemented within the experimental facility's hardware. Overall, the proposed versatile innovation platform is expected to provide valuable insights for advancing research in the field of small modular reactors and nuclear-based hydrogen production.

• Nuclear Engineering and Technology
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• 제56권5호
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• pp.1687-1697
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• 2024

This study presents the Supporting platform for reactor fine flow characteristics calculation and analysis (Cilian platform), a user-friendly tool that supports the analysis and optimization of pressurized water reactor (PWR) cores with mixing vanes using computational fluid dynamics (CFD) computing. The Cilian platform allows for easy creation and optimization of PWR's main CFD calculation schemes and autonomously manages CFD calculation and analysis of PWR cores, reducing the need for human and computational resources. The platform's key features enable efficient simulation, rapid solution design, automatic calculation of core scheme options, and streamlined data extraction and processing techniques. The Cilian platform's capability to call external CFD software reduces the development time and cost while improving the accuracy and reliability of the results. In conclusion, the Cilian platform exemplifies an innovative solution for efficient computational fluid dynamics analysis of pressurized water reactor (PWR) cores. It holds great promise for driving advancements in nuclear power technology, enhancing the safety, efficiency, and cost-effectiveness of nuclear reactors. The platform adopts a modular design methodology, enabling the swift and accurate computation and analysis of diverse flow regions within core components. This design approach facilitates the seamless integration of multiple computational modules across various reactor types, providing a high degree of flexibility and reusability.

• 한국산학기술학회논문지
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• 제15권12호
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• pp.7025-7039
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• 2014

최근 구매사와 공급사 간의 정보 공유 및 협업 등의 아웃소싱 활동은 공급사슬관리에서 매우 중요한 전략으로 자리매김하고 있다. 아웃소싱은 경쟁우위 확보를 위해 필수적인 방안으로 활용되고 있으나, 계약이 체결된 이후에는 공급사에 대한 통제력이 저하된다. 이러한 상황에서는 공급사에 대한 모니터링을 통한 일상적인 통제만이 유일한 공식적 통제수단으로 남게 되며, 통제관리가 어떻게 이루어지느냐에 따라 기업성과에 영향을 미치게 된다. 본 연구에서는 아웃소싱 계약 체결 이후 공급사의 외주 구매성과와 구매사와 공급사 간의 운영통합 강화를 위한 전략을 제시하였다. 선행요인으로 공급사 모니터링을 고려하였으며, 공급사 모니터링 노력에 의한 외주 구매성과와 구매사와 공급사 간 운영통합을 강화하여 구매사의 현장생산성 향상으로 반영되는 연구 모형을 제시하였다. 연구결과에 따르면, 구매사의 역량 모니터링, 행위 모니터링, 결과 모니터링은 공급사의 외주 구매성과와 운영통합 강화에 유의미한 선행요인으로 나타났다. 또한, 공급사 모니터링은 공급사의 외주 구매성과와 공급사 운영통합을 완전매개로 하여 구매사의 현장생산성에 유의미한 영향을 미치는 것으로 분석되었다. 행위 모니터링의 부정적인 효과가 특이한 점으로 나타났는데, 행위 모니터링이 공급사 운영통합에 음(-)의 효과는 공급사 운영통합이 공급사 현장생산성 향상에 미치는 정(+)의 효과를 상쇄시키기 때문에 매개효과가 나타나지 않은 것으로 추정되었다. 이를 통해 이론적, 실무적 시사점과 본 연구의 한계점, 향후 연구수행 방안 등이 제시되었다.