• Journal of Electrical Engineering and Technology
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• 제12권3호
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• pp.1046-1052
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• 2017

The load on the power grid of South Korea is expected to grow continuously until the late 2020s, and it is necessary to increase the transfer capacity from the Eastern grid to the Seoul-Gyeonggi region by reinforcing the transmission network for the electric power system to remain stable. To this end, the grid reinforcement by two bipole LCC HVDC transmission systems have been considered on account of the public acceptability and high growth of the fault current level, even though an additional 765kV system construction is more economical. Since the probability of the existing 765kV double circuit transmission line trip is extremely low, a dynamic simulation study was carried out to estimate the efficient HVDC capacity able to stabilize the transient stability by utilizing the HVDC overload capability. This paper suggests the application plan to reduce the HVDC construction capacity with ensuring the transient stability during the 765kV line trip.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 D
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• pp.2036-2038
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• 2001

In this paper, we propose the neural network based emotion recognition method for intelligently recognizing the human's emotion using vision system. In the proposed method, human's emotion is divided into four emotion (surprise, anger, happiness, sadness). Also, we use R,G,B(red, green, blue) color image data and the gray image data to get the highly trust rate of feature point extraction. For this, we propose an algorithm to extract four feature points (eyebrow, eye, nose, mouth) from the face image acquired by the color CCD camera and find some feature vectors from those. And then we apply back-prapagation algorithm to the secondary feature vector(position and distance among the feature points). Finally, we show the practical application possibility of the proposed method.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권10호
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• pp.4724-4747
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• 2016

To efficiently reduce on-grid energy consumption, the admission control algorithm in the hybrid energy powered cellular network (HybE-Net) with base stations (BSs) powered by on-grid energy and solar energy is studied. In HybE-Net, the fluctuation of solar energy harvesting and energy consumption may result in the imbalance of solar energy utilization among BSs, i.e., some BSs may be surplus in solar energy, while others may maintain operation with on-grid energy supply. Obviously, it makes solar energy not completely useable, and on-grid energy cannot be reduced at capacity. Thus, how to control user admission to improve solar energy utilization and to reduce on-grid energy consumption is a great challenge. Motivated by this, we first model the energy flow behavior by using stochastic queue model, and dynamic energy characteristics are analyzed mathematically. Then, fuzzy logic based admission control algorithm is proposed, which comprehensively considers admission judgment parameters, e.g., transmission rate, bandwidth, energy state of BSs. Moreover, the index of solar energy utilization balancing is proposed to improve the balance of energy utilization among different BSs in the proposed algorithm. Finally, simulation results demonstrate that the proposed algorithm performs excellently in improving solar energy utilization and reducing on-grid energy consumption of the HybE-Net.

• 교육시설 논문지
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• 제26권1호
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• pp.17-23
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• 2019

Nowadays, the concept of outdoor campus is different from the past. U-Campus with a well-developed high-speed computer network is no longer a constraint on the campus interior and exterior spaces. From this point of view, today's large-scale university outdoor spaces need to be changed from a simple green space. The university campus outdoor spaces need to be changed into a new concept space. This study analyzed the changes in academic activities and preferences of college students who are users of university campus outdoor spaces and it is aimed at space planning that reflects the preference. The university campus should be remodified through changes in students' behaviors. Participants in this study were four different departments students (Social science, Physical education, Natural science and Engineering). The preference results of 17 items were analyzed. As a result of this preference analysis, we found that there is a difference in preference among students belonging to four different departments students. In conclusion, this study will propose that the preferences of each college should be considered in planning the outdoor rest spaces of university campus.

• Computers and Concrete
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• 제27권3호
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• pp.185-197
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• 2021

Throughout the previous years, many efforts focused on incorporating non-biodegradable wastes as a partial replacement and sustainable alternative for natural aggregates in cement-based materials. Currently, rubberized concrete is considered one of the most important green concrete materials produced by replacing natural aggregates with rubber particles from old tires in a concrete mixture. The main benefits of this material, in addition to its importance in sustainability and waste management, comes from the ability of rubber to considerably damp vibrations, which, when used in reinforced concrete structures, can significantly enhance its energy dissipation and vibration behavior. Nowadays, the literature has many experimental findings that provide an interesting view of rubberized concrete's dynamic behavior. On the other hand, it still lacks research that collects, interprets, and numerically investigates these findings to provide some correlations and construct reliable prediction models for rubberized concrete's dynamic properties. Therefore, this study is intended to propose prediction approaches for the dynamic properties of rubberized concrete. As a part of the study, multiple linear regression and artificial neural networks will be used to create prediction models for dynamic modulus of elasticity, damping ratio, and natural frequency.

• 농촌계획
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• 제28권2호
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• pp.11-20
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• 2022

As a portal to rural town, Myeon near large cities is expected to represent image of the rural area. But, the landscape are changing rapidly due to development pressure and to the expansion of the transportation network. For visitors and transit traffic, Recognizing that the characteristics of the streetscape is an important task for the vitalization of the rural district. In particular, it was found that the visual quantity of the central street in the location of the town was closely related to the preference of the streetscape, and the visual quantity of trees and the visual quantity of the building showed an inverse relationship of + and - respectively. Since this is not a simple ratio of the sky to the building, but a relative factor, the possibility of landscape improvement can be improved through management of public facilities or green spaces and maintenance of open spaces or gaps between buildings. It seems that it is necessary to secure separate means for the management of the architectural landscape, such as the establishment of a special landscape plan or establishment of ordinances.

• 유통과학연구
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• 제20권7호
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• pp.47-56
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• 2022

Purpose: As the need to transition into the distribution of cleaner energy has garnered corporate and scholarly interests, this study aims to track the research trends in sustainable energy supply chains for five years before 2021. Research methodology: This study was conducted by a bibliometric literature review and analysis to map the field's evolution between 2016 and 2020. Out of an initial title search result of 2,484 papers from the Scopus engine, filtering led to 180 documents obtained. The data was exported in excel format (CSV) to VOSviewer software to generate and analyze network visualization of sustainable energy supply chain trends. Results: The results revealed China's the highest publishing country, with 36 research papers. The Journal of Cleaner Production was the top publishing source, with 22 papers per year. These findings showed five clusters formed in the bibliographic coupling of countries. Circular Economy and Green Supply Chain Management represent the current hot topics. Research gaps identified in the field included limited cross-industry testing and modifying sustainable supply chain models. Conclusion: This paper contributes to the sustainability literature on supply chains by providing an overview of trends and research directions for scholars' and practitioners' consideration in future research.

• Steel and Composite Structures
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• 제49권6호
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• pp.645-666
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• 2023

Due to the steadily declining supply of natural coarse aggregates, the concrete industry has shifted to substituting coarse aggregates generated from byproducts and industrial waste. Oil palm shell is a substantial waste product created during the production of palm oil (OPS). When considering the usage of OPSC, building engineers must consider its uniaxial compressive strength (UCS). Obtaining UCS is expensive and time-consuming, machine learning may help. This research established five innovative hybrid AI algorithms to predict UCS. Aquila optimizer (AO) is used with methods to discover optimum model parameters. Considered models are artificial neural network (AO - ANN), adaptive neuro-fuzzy inference system (AO - ANFIS), support vector regression (AO - SVR), random forest (AO - RF), and extreme gradient boosting (AO - XGB). To achieve this goal, a dataset of OPS-produced concrete specimens was compiled. The outputs depict that all five developed models have justifiable accuracy in UCS estimation process, showing the remarkable correlation between measured and estimated UCS and models' usefulness. All in all, findings depict that the proposed AO - XGB model performed more suitable than others in predicting UCS of OPSC (with R², RMSE, MAE, VAF and A_15-index at 0.9678, 1.4595, 1.1527, 97.6469, and 0.9077). The proposed model could be utilized in construction engineering to ensure enough mechanical workability of lightweight concrete and permit its safe usage for construction aims.

• Asia pacific journal of information systems
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• 제30권3호
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• pp.513-531
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• 2020

Online Word-of-Mouth communication, or eWOM, has dramatically changed the way people network, interact, and share knowledge. Studies have examined why consumers choose to share knowledge online, especially online product reviews, as well as the motivations of individuals to share product ideas online. However, the role of gender in shaping the motivation and types of knowledge shared online has been given little consideration. Using concepts from Social Exchange Theory and the Theory of Reasoned Action, we address this research gap by developing and testing a model of gender's influence on knowledge sharing in a social media context. A PLS analysis of survey data from 257 students indicates that reputation, altruism, and subjective norms are key motivators for knowledge sharing intention in social media. More importantly, that gender plays a moderating role within the motivation-knowledge sharing relationship. We also find that subjective norms have a greater impact on knowledge sharing with women than with men. Collectively, our research results highlight individualized factors for improving customer participation in external facing social media for marketing and product innovation.

• 한국조경학회지
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• 제43권6호
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• pp.86-97
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• 2015

'자연마당 조성사업'은 도시 내 생태휴식공간이자 생활문화공간 창출을 위해 추진되는 환경부의 사업이다. 경상남도 밀양시 내일동 아북산 일대는 훼손된 상태로 오랜 기간 방치되면서 생태복원이 필요한 장소로 인식되어 올해 자연마당 조성사업의 대상지가 되었다. 본 연구의 목적은 시스템 다이내믹스를 활용하여 아북산 일대의 생태복원을 위한 설계전략을 도출하는 것이다. 사업대상지의 핵심 복원 공간으로써 국궁장, 구덩이, 경작지 부지는 각각의 문제점을 안고 있다. 본 연구에서는 이러한 문제점 해결을 위해 인과지도를 작성하여 현황을 파악하고 핵심 전략을 도출하였으며 전략을 토대로 설계안을 마련하였다. 첫째, 국궁장 부지의 경우 토양 산성화와 녹지축 단절의 문제 해결을 위한 전략으로 녹비식물과 후글컬쳐 방식을 도출하여 실제 설계안에 도입하였고, 둘째, 구덩이 부지의 경우 구덩이 하단부에 우수가 집수되어 습윤성 식생이 출현한 점에서 인공 습지 조성 가능성을 타진하고 생태 문화적 이점을 파악하여 인공 습지 조성의 설계안을 마련하였다. 셋째, 두 곳으로 분리되는 경작지 부지는 토양 산성화와 토양 침식, 녹지축 단절의 문제 해결을 위해 토양 개량 작업 후 한 곳은 자생종을 식재하여 산림을 복원하는 전략 도출을 통해 녹지축을 연결하는 설계안을 완성하였고 다른 한 곳은 초지로 복원하되 일부 공간에 건습지를 조성하는 설계안을 세웠다. 본 연구는 생태복원 설계 시 생태계 시스템의 피드백 루프 내에서 문제점을 파악하여 전략을 도출한 것으로써 일반적인 설계 과정에 없던 시스템 사고의 방식을 시도했다는 것에 의의가 있다.