• Structural Engineering and Mechanics
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• 제88권3호
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• pp.221-238
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• 2023

This paper developed and examined a novel passive vibration isolator (i.e., "X-inerter") motivated by combining a bio-inspired structure and a rack-pinion inerter. The bio-inspired structure provided nonlinear stiffness and damping owing to its geometric nonlinearity. In addition, the behavior was further enhanced by a gear inerter that produced a special nonlinear inertia effect; thus, an X-inerter was developed. As a result, the X-inerter can achieve both high-static-low-dynamic stiffness (HSLDS) and quasi-zero stiffness (QZS), obtaining ultra-low frequency isolation. Furthermore, the installed inerter can produce a coupled nonlinear inertia and damping effect, leading to an anti-resonance frequency near the resonance, wide isolation region, and low resonance peak. Both static and dynamic analyses of the proposed isolator were conducted and the structural parameters' influence was comprehensively investigated. The X-inerter was proven to be comparatively more stable in the ultra-low frequency than the benchmarking QZS isolator due to the nonlinear damping and inertia properties. Moreover, the inertia effect could suppress the bio-inspired structure's super- and sub-harmonic resonance. Therefore, the X-inerter isolator generally possesses desirable nonlinear stiffness, nonlinear damping, and unique nonlinear inertia, designed to achieve the ultra-low natural frequency, the anti-resonance property, and a wide isolation region with a low resonance peak.

• 한국경제지리학회지
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• 제26권3호
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• pp.324-336
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• 2023

이 연구의 목적은 프랑스의 거버넌스형 도시재생 추진기구인 ANRU의 특성을 살펴보고, 국내 도시재생사업에 활용 가능한 정책적 시사점을 살펴 보는 것이다. 연구결과를 요약하면 다음과 같다. 첫째로, 프랑스에서는 국가차원의 거버넌스형 도시재생 추진기구로서 ANRU가 설립, 운영되고 있으며, ANRU는 중앙주도형 도시재생 추진기구이지만, 다양한 도시재생사업의 주체들이 참여하는 거버넌스 방식의 운영을 지향한다. 둘째로, ANRU는 PNRU, NPNRU, PNRQAD 등 3개의 도시재생 프로그램을 전국적으로 운영하고 있으며, 이에 따른 행정 및 재정지원을 통해, 사업지구 내 주거환경의 개선, 도시기능의 다양화, 경제 개발, 사회적 다양성 증대 등을 도모하고 있다. 셋째로, 국내의 도시재생사업에 주는 정책적 시사점으로, 도시재생사업의 효과적인 추진과 가시적 성과를 위한 국가차원의 거버넌스형 도시재생 추진기구의 필요성, 자치단체 간 연대의 필요성, 다양한 차원의 민관 파트너십 활용의 필요성을 제안하였다.

• 한국경제지리학회지
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• 제26권2호
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• pp.137-154
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• 2023

본 연구의 목적은 도시재생사업의 효과적인 추진과 사업구조 구축을 위해, 거버넌스의 관점에서 민관 파트너십의 활용 방안을 모색하는 것이다. 연구결과를 요약하면 다음과 같다. 첫째로, 거버넌스의 관점에서 본 도시재생사업에서의 민관 파트너십 유형은 중앙정부 주도형, 지방정부 주도형, 민간사업자 주도형, 지역주민·커뮤니티조직 주도형으로 분류할 수 있다. 둘째로, 해외사례 분석을 통해 선진국들은 다양한 민관 파트너십의 구성을 통해 도시재생사업을 효과적으로 추진하고 있음이 확인된다. 셋째로, 국내의 도시재생사업에서 민관 파트너십 활용 방안으로, 도시재생사업의 유형과 규모의 다양화 방안 마련, 다양한 민관 파트너십 활용을 위한 제도설계 마련, 다양한 민간참여의 활용을 위한 교차보조 방식의 활용, 투명하고 효과적인 민관 파트너십에 필요한 사회적 자본의 형성 방안 마련을 제안하였다.

• Computers and Concrete
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• 제32권6호
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• pp.577-594
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• 2023

Engineered cementitious composites with calcined clay limestone cement (LC³-ECC) as a kind of green, low-carbon and high toughness concrete, has recently received significant investigation. However, the complicated relationship between potential influential factors and LC³-ECC compressive strength makes the prediction of LC³-ECC compressive strength difficult. Regarding this, the machine learning-based prediction models for the compressive strength of LC³-ECC concrete is firstly proposed and developed. Models combine three novel meta-heuristic algorithms (golden jackal optimization algorithm, butterfly optimization algorithm and whale optimization algorithm) with support vector regression (SVR) to improve the accuracy of prediction. A new dataset about LC³-ECC compressive strength was integrated based on 156 data from previous studies and used to develop the SVR-based models. Thirteen potential factors affecting the compressive strength of LC³-ECC were comprehensively considered in the model. The results show all hybrid SVR prediction models can reach the Coefficient of determination (R²) above 0.95 for the testing set and 0.97 for the training set. Radar and Taylor plots also show better overall prediction performance of the hybrid SVR models than several traditional machine learning techniques, which confirms the superiority of the three proposed methods. The successful development of this predictive model can provide scientific guidance for LC³-ECC materials and further apply to such low-carbon, sustainable cement-based materials.

• 한국재난정보학회 논문집
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• 제20권2호
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• pp.448-461
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• 2024

연구목적: 본 연구는 포스트 코로나 시대에 생활 SOC 시설을 설치하고, 운영하기 위해 우리나라 특성에 적합한 생활권 위계를 설정하고, 유형을 구분하는 것을 목적으로 한다. 연구방법: 생활권과 관련된 정책과 선행연구들을 통해 생활권의 개념을 정립하였고, 생활권 위계에 따라 생활권의 유형을 인구, 고용, 교통, 경제, 교육 등 다양한 분야의 데이터를 z-score 기법을 이용하여 유형구분을 하였다. 연구결과: 우리나라 생활권은 규모에 따라 광역생활권, 권역생활권, 도시생활권, 마을생활권, 동네생활권으로 구분할 수 있으며, 역할에 따라 중심생활권, 직주균형생활권, 주거생활권, 산업생활권, 저밀생활권으로 유형구분을 할 수 있다. 결론: 본 연구의 결과는 타당한 생활권 설정과 적절한 생활 SOC공급은 낙후지역의 쇠퇴를 막고, 지역 간 균형발전에 기여할 수 있다

• 대순사상과 동아시아종교
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• 제3권2호
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• pp.71-92
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• 2024

The world we live in is becoming more convenient thanks to the inventions of science and technology. Still, the world is also becoming more and more unpredictable with the current situation of VUCA (Volatility, Uncertainty, Complexity, Ambiguity). The Covid-19 pandemic brought the biggest global disaster ever with 774,631,444 infected people and 7,031,216 deaths (WHO on February 11, 2024) but it seems that humanity is gradually forgetting this disaster. Meanwhile the economic stimulus packages worth trillions of dollars from governments after the pandemic have further caused the world debt bubble to swell. The bubble burst scenario is something that many economic experts fear. Apparently, in the transitional period of the early decades of the 21st century, the world's economic, cultural, political, social, natural, and environmental aspects have undergone profound transformations: from the real estate and finance crises in the United States since 2008; through the melting of the Arctic ice over the past several decades; to the double disaster of the earthquake and tsunami in Japan in 2011. Especially, in the context of the world economic crisis after the COVID-19 pandemic, the human achievements of the past thousands of years are in jeopardy of being wiped out in an instant. Many people are predicting a bad scenario for a chain collapse. Facing the signals of an imminent economic catastrophe based on the appearance of "the Gray Rhino, Black Swan and White Elephant," many drawn in by Eschatological thought declare that Doomsday will occur shortly. This is the time for many other people to hope for the incoming Messiah. The Messiah is said to appear when people feel despair or suffer a great disaster because faith in the Savior can help them overcome adversity mentally. This research will find out how adherents of Buddhism view and deal with civilizational crises by examining history via symbols associated with Maitreya as based upon the Buddhist Messiah, Maitreya.

• 유기물자원화
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• 제31권4호
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• pp.5-11
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• 2023

본 연구는 하수 탈수찌꺼기가 건조기에 직 투입되는 경우 함수율 40~60% 구간에서 발생하는 Glue Zone에서 뭉침 및 Fouling 현상 등의 문제점 및 에너지효율 개선을 하기 위해 수행하였다. 열풍 온도는 270~300℃로 낮게, 패들타입의 부상방식과 순환되어진 축열 메디아에 탈수찌꺼기가 도포되어 열풍과의 접촉면적을 증대시켜 에너지 회수 및 가스 배출량을 감소시켰으며, 건조 찌꺼기의 함수율은 2.7~7.5%, 수분 증발열량은 608.0~690.6kcal/kg·H₂O로 축열 메디아 미투입 시 수분 증발열량 714.5 kcal/kg·H₂O과 비교하여 약 8.8%의 에너지 절감 효과를 확인하였다.

• Earthquakes and Structures
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• 제26권3호
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• pp.175-189
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• 2024

Aiming at studying the plastic hinge (PH) evolution regularities and failure mode of rocking wall moment frame (RWMF) structure in earthquakes, the whole-working history analysis of seismic performance state of RWMF structure based on co-operation performance and PH evolution was carried out. Building upon the theoretical analysis of the elastic internal forces and deformations of RWMF structures, nonlinear finite element analysis (FEA) methods were employed to perform both Pushover analysis and seismic response time history analysis under different seismic coefficients (δ). The relationships among PH occurrence ratios (R_ph), inter-story drifts and δ were established. Based on the plotted curve of the seismic performance states, evaluation limits for the R_ph and inter-story drifts were provided for different performance states of RWMF structures. The results indicate that the R_ph of RWMF structures exhibits a nonlinear evolution trend of "fast at first, then slow" with the increasing of δ. The general pattern is characterized by the initial development of beam hinges in the middle stories, followed by the development towards the top and bottom stories until the beam hinges are fully formed. Subsequently, the development of column hinges shifts from the bottom and top stories towards the middle stories of the structure, ultimately leading to the loss of seismic lateral capacity with a failure mode of partial beam yield, demonstrating a global yielding pattern. Moreover, the limits for the R_ph and inter-story drifts effectively evaluate the five different performance states of RWMF structures.

• 한국재난정보학회 논문집
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• 제20권1호
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• pp.138-146
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• 2024

연구목적: 본 연구는 대설 상황 발생시 신속하고 효율적인 도로 제설을 위해 제설 차량과 장비 등에 정보통신기술과 스마트 모빌리티 기술을 활용한 사례들을 찾아보고, 활용방안을 모색하는 것을 목적으로 한다. 연구방법: 국내 및 해외 제설작업 방법에 대한 사례를 조사하고 신 기술을 접목한 제설운영방법을 제시한다. 연구결과: 우리나라 제설장비 운영은 GPS와 CCTV, 도로교통 정보시스템을 활용한 방법이 대부분이며 해외의 경우 도로기상 정보시스템과 도로제설모니터링 시스템을 활용한다. 향후 스마트모빌리티인 자율주행 제설차량을 활용한 제설기술이 개발 될 것을 기대한다. 결론: 본 연구의 결과는 지자체 및 관련 기관의 제설 장비와 제설 차량 활용 정책에 기여할 수 있다.

• 한국환경과학회지
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• 제33권3호
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• pp.193-203
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• 2024

This study aims to determine the factors affecting the level of satisfaction with the Cell Broadcast Service (CBS) among citizens in Incheon. Partial least squares (PLS) regression, instead of multiple regression, was used for the analysis because it can solve multicollinearity and sample size issues. The analysis results are as follows: The factor with the greatest effect on satisfaction with CBS among Incheon citizens, was the elimination of redundancies (VIP=1.185). Therefore, local governments, government agencies, and public organizations must coordinate their ideas and collectively create guidelines to eliminate redundancies. The second most influential factor was the expansion in the broadcast medium from legal, institutional, and policy aspects (VIP=1.087). This is because differences in generation, age, gender, and personal characteristics were not considered. Therefore, it is necessary to devise a customized messaging tool through the expansion of broadcast media. The broadcast criteria of the legal, institutional, and policy perspectives comprised the third most influential factor, with a high VIP value of 1.053. Consequently, it is essential to devise a plan to avoid distributing unnecessary cell broadcast services, by establishing criteria for areas and sections, time, and the direct and indirect impact zones of a disaster. In the future, this study could be used as base data to develop policies, guidelines, and response measures for Incheon CBS. Given the lack of research on the diverse characteristics of each social class and the city traits of each region, and a lack of concrete empirical research on each factor, continuous and in-depth studies are required in the future.