• Structural Engineering and Mechanics
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• 제78권1호
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• pp.77-86
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• 2021

Local school buildings are critical facilities that can provide shelter in disasters such as earthquakes, so they must be more resistant to seismic forces than other structures. In this study, a sensitivity analysis was conducted to determine which columns-as the most critical members in a reinforced concrete building-most urgently require seismic retrofitting. The sensitivity analysis was conducted using an optimization technique with the location of each column as a parameter. A numerical model was developed to simulate a realistic collapse mode through a three-dimensional dynamic analysis. Based on numerical analysis results, it was found that the columns positioned in the lower floors, such as the first floor and in the outer part of a building, urgently require retrofitting. For reinforcement of the RC columns, which has been proven for its performance in previous research, was applied. Through this study, the importance of appropriate retrofitting is demonstrated. Further, a method for determining the appropriate location for retrofitting-when retrofitting is not possible on the entire structure-is presented.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2022년도 추계학술대회
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• pp.411-413
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• 2022

본 논문에서는 FoV(Fiele Of View)에 따른 감지거리 변화와 반사체에 따른 감지거리 고려하여 TOF(Time Of Flight) 센서의 장착 위치를 측면부 설치 시와 전/후면부 설치 시로 나누어 맞춘 개발을 수행하도록 한다.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 2008년도 춘계학술 발표회
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• pp.217-222
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• 2008

In the last five years, 45 people died and 104 were wounded because of carbon monoxide poisoning accident. CO poisoning accident is higher than any other gas accident in the rate of deaths/incidents. Most of these CO poisoning accidents were caused by defective exhaust tube in the old gas boiler and multi-use facility. In this study, the spread of CO gas released from leakage hole of exhaust tube was analyzed by concentration measuring test. CO gas leaked form exhaust tube in a building was highest concentrated near the ceiling. Through these experiments, the reasonable installation location of CO alarm was made certain and suggested.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.523-524
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• 2011

This paper covers induced voltage in parallel telecommunication cable with underground power cable to be linked between substations. The simulation was carried out the induced voltage in telecommunication cable according to the transposition of power cables and fault location for various conditions. This study based on the EMTP/ATPDraw with actual underground cable systems while the power cables are in steady state and transient state.

• Molecules and Cells
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• 제45권5호
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• pp.273-283
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• 2022

During meiosis, homologous chromosomes (homologs) pair and undergo genetic recombination via assembly and disassembly of the synaptonemal complex. Meiotic recombination is initiated by excess formation of DNA double-strand breaks (DSBs), among which a subset are repaired by reciprocal genetic exchange, called crossovers (COs). COs generate genetic variations across generations, profoundly affecting genetic diversity and breeding. At least one CO between homologs is essential for the first meiotic chromosome segregation, but generally only one and fewer than three inter-homolog COs occur in plants. CO frequency and distribution are biased along chromosomes, suppressed in centromeres, and controlled by pro-CO, anti-CO, and epigenetic factors. Accurate and high-throughput detection of COs is important for our understanding of CO formation and chromosome behavior. Here, we review advanced approaches that enable precise measurement of the location, frequency, and genomic landscapes of COs in plants, with a focus on Arabidopsis thaliana.

• ETRI Journal
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• 제45권2호
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• pp.203-212
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• 2023

In this study, we developed a co-located and space-shared multiple-input multiple-output (MIMO) antenna module with a modular design and high integration level. The proposed antenna pair includes a half-wavelength loop antenna and a dipole-type antenna printed on the front and back sides of a compact modular board. Owing to their modal orthogonality, these two independent antenna elements are highly self-isolated and free of additional decoupling components, even though they are assembled at the same location and within the same space. Thus, the proposed antenna is attractive in 5G MIMO systems. Furthermore, the proposed co-located and space-shared MIMO antenna module was employed in a 5G smartphone to verify their radiation and diversity performances. A 12 × 12 MIMO antenna system was simulated and fabricated using the proposed module. Based on the results, the proposed module can be employed in large-scale MIMO antenna systems for current and future terminal devices owing to its high integration, compactness, simple implementation, and inherent isolation.

• IMMUNE NETWORK
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• 제21권1호
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• pp.3.1-3.16
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• 2021

Coronavirus disease 2019 caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been spreading worldwide since its outbreak in December 2019, and World Health Organization declared it as a pandemic on March 11, 2020. SARS-CoV-2 is highly contagious and is transmitted through airway epithelial cells as the first gateway. SARS-CoV-2 is detected by nasopharyngeal or oropharyngeal swab samples, and the viral load is significantly high in the upper respiratory tract. The host cellular receptors in airway epithelial cells, including angiotensin-converting enzyme 2 and transmembrane serine protease 2, have been identified by single-cell RNA sequencing or immunostaining. The expression levels of these molecules vary by type, function, and location of airway epithelial cells, such as ciliated cells, secretory cells, olfactory epithelial cells, and alveolar epithelial cells, as well as differ from host to host depending on age, sex, or comorbid diseases. Infected airway epithelial cells by SARS-CoV-2 in ex vivo experiments produce chemokines and cytokines to recruit inflammatory cells to target organs. Same as other viral infections, IFN signaling is a critical pathway for host defense. Various studies are underway to confirm the pathophysiological mechanisms of SARS-CoV-2 infection. Herein, we review cellular entry, host-viral interactions, immune responses to SARS-CoV-2 in airway epithelial cells. We also discuss therapeutic options related to epithelial immune reactions to SARS-CoV-2.

• 지구물리와물리탐사
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• 제20권1호
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• pp.1-11
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• 2017

P파 및 S파의 초동주시를 활용한 역산기법들을 통해 미소지진 모니터링의 진원위치의 정확도를 향상시키기 위해 시추공 3성분 수진기를 이용한 현장실험이 수행되었다. 3성분 수진기의 수평 $\times$ 성분을 자북방향으로 정렬시키고 중추낙하형 발생원을 이용한 실험을 통해 계측자료의 P파 초동의 입자움직임으로부터 진원의 방향을 추정할 수 있었다. 한편 계측자료에서 S파의 식별이 어려운 경우에도 편극필터의 적용으로 S파의 초동주시를 발췌할 수 있었다. P파 초동주시만을 이용한 역산기법은 진원위치에 대한 초기치가 진원으로부터 크게 이격되면 국부적인 최소값으로 수렴하여 정해를 찾지 못하는 경우가 있다. 본 연구에서는 이러한 문제를 해결하기 위해 P파와 S파의 초동주시 차이를 이용한 진원위치 결정방법과 P파 초동주시만을 이용한 역산을 복합적으로 사용한 결과 진원위치의 정확도를 향상시킬 수 있었다.

• Journal of Electrical Engineering and Technology
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• 제8권3호
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• pp.638-648
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• 2013

Together with the GPS-based approach, geo-location through mobile communication networks is a key technology for location-based service. To save the cost, most geo-location system is implemented on the existed network service, which has a cellular structure. Still, multilateration is limited in cellular structure because it is difficult for the mobile terminal to acquire distance measurements from multiple base stations. This low hearability in the receiver is caused by co-channel interference and multipath environment. Therefore, hearability enhancement is necessary for multilateration under multipath and interference environment. Former time domain based hearability methods were designed for real signals. However, orthogonal frequency division multiplexing (OFDM) signal, which its usage has been increased in digital wireless communication, is a complex signal. Thus, different hearability enhancement method is needed for OFDM signals. This paper proposes a hearability enhancement method for forward-link multilateration using OFDM signals, which employ interference cancellation and multipath mitigation. A novel interference cancellation and multipath mitigation strategy for complex-valued OFDM signals is presented that has an iterative structure. Simulation results show that the proposed multilateration method provides the user's position with an accuracy of less than 80m through the mobile WiMAX cellular network in multipath environment.

• 대한원격탐사학회지
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• 제39권6_1호
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• pp.1309-1320
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• 2023

모바일 기기의 기술 발전과 대중화는 어디서든 사용자의 위치를 확인할 수 있으며 인터넷을 사용할 수 있도록 발전되었다. 그러나 실내의 경우 인터넷은 끊김없이 사용할 수 있지만 global positioning system (GPS) 기능은 활용하기 어렵다. 실내 공공장소인 백화점, 박물관, 컨퍼런스장, 학교, 터널 등 GPS가 수신되지 않는 음영 지역에서 실시간 위치정보 제공의 필요성이 증가하고 있다. 이에 따라 최근의 실내 측위 기술은 랜드마크 데이터베이스를 구축하기 위해 light detection and ranging (LiDAR) 장비를 기반으로 연구가 증가하고 있다. 본 연구에서는 랜드마크 데이터베이스 구축의 접근성에 초점을 두어 모바일 기기를 기반으로 랜드마크를 촬영한 단일 이미지와 사전에 구축된 랜드마크 데이터베이스 정보를 이용하여 사용자의 위치를 추정하는 기법을 개발하고자 하였다. 첫 번째로, 랜드마크 데이터베이스를 구축하였다. 랜드마크를 촬영한 모바일 이미지만으로 사용자 위치를 추정하기 위해서는 모바일 이미지에서 랜드마크 검출이 필수적이고, 검출된 랜드마크에서 고정적인 성격을 가진 지점의 지상좌표 취득이 필수적이다. 두 번째 단계에서는 bag of words (BoW) 영상 검색 기술을 적용해 랜드마크 데이터베이스 중 모바일 이미지가 촬영한 랜드마크를 유사한 4위까지 검색하였다. 세 번째 단계에서는 scale invariant feature transform (SIFT) 특징점 추출 기법과 Homography random sample consensus (RANSAC)을 통해 검색된 4개의 후보 랜드마크들 중 가장 유사한 하나의 랜드마크를 선정하였고, 이때 임계값 설정을 통해 정합점 수를 기반으로 한 차례 더 필터링을 수행하였다. 네 번째 단계에서는 대응된 랜드마크와 모바일 이미지간의 Homography 행렬을 통해 랜드마크 이미지를 모바일 이미지에 투사하여 랜드마크의 영역과 코너(외곽선)점을 검출하였다. 마지막으로, 위치추정 기법을 통해 사용자의 위치를 추정하였다. 해당 기술의 성능을 분석한 결과, 랜드마크 검색 성능은 약 86%로 측정되었다. 위치추정 결과와 사용자의 실제 지상좌표를 비교한 결과, 약 0.56 m의 수평 위치 정확도를 갖는 것이 확인되어 별도의 고가 장비 없이 랜드마크 데이터베이스를 구축하여 모바일 영상으로 사용자 위치 추정이 가능한 것을 확인하였다.