• Composites Research
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• v.34 no.1
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• pp.35-46
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• 2021

This paper aims to reduce weight by replacing the reinforcements of the B-pillar used in vehicles with CFRP(Carbon Fiber Reinforced Plastics) and GFRP(Glass Fiber Reinforced Plastics) from the existing steel materials. For this, it is necessary to secure structural stability that can replace the existing B-pillar while reducing the weight. Existing B-pillar are composed of steel reinforcements of various shapes, including a steel outer. Among these steel reinforcements, two steel reinforcements are to be replaced with composite materials. Each steel reinforcement is manufactured separately and bonded to the B-pillar outer by welding. However, the composite reinforcements presented in this paper are manufactured at once through compression and injection processes using patch-type CFRP and rib-structured GFRP. CFRP is attached to the high-strength part of the B-pillar to resist side loads, and the GFRP ribs are designed to resist torsion and side loads through a topology optimization technique. Through structural analysis, the designed composite B-pillar was compared with the existing B-pillar, and the weight reduction ratio was calculated.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.1
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• pp.141-148
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• 2021

In some intersections or busy traffic roads, there are more pedestrians in a specific period of time, and there are many traffic accidents caused by road congestion. Especially at the intersection where there are schools nearby, it is particularly important to protect the traffic safety of students in busy hours. In the past, when designing traffic lights, the safety of pedestrians was seldom taken into account, and the identification of motor vehicles and traffic optimization were mostly studied. How to keep the road smooth as far as possible under the premise of ensuring the safety of pedestrians, especially students, will be the key research direction of this paper. This paper will focus on person, motorcycle, bicycle, car and bus recognition research. Through investigation and comparison, this paper proposes to use YOLO v4 network to identify the location and quantity of objects. YOLO v4 has the characteristics of strong ability of small target recognition, high precision and fast processing speed, and sets the data acquisition object to train and test the image set. Using the statistics of the accuracy rate, error rate and omission rate of the target in the video, the network trained in this paper can accurately and effectively identify persons, motorcycles, bicycles, cars and buses in the moving images.

• Journal of Broadcast Engineering
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• v.26 no.3
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• pp.247-257
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• 2021

This paper proposes a new technique for calibrating a multi-view RGB-D camera using a 3D (dimensional) skeleton. In order to calibrate a multi-view camera, consistent feature points are required. In addition, it is necessary to acquire accurate feature points in order to obtain a high-accuracy calibration result. We use the human skeleton as a feature point to calibrate a multi-view camera. The human skeleton can be easily obtained using state-of-the-art pose estimation algorithms. We propose an RGB-D-based calibration algorithm that uses the joint coordinates of the 3D skeleton obtained through the posture estimation algorithm as a feature point. Since the human body information captured by the multi-view camera may be incomplete, the skeleton predicted based on the image information acquired through it may be incomplete. After efficiently integrating a large number of incomplete skeletons into one skeleton, multi-view cameras can be calibrated by using the integrated skeleton to obtain a camera transformation matrix. In order to increase the accuracy of the calibration, multiple skeletons are used for optimization through temporal iterations. We demonstrate through experiments that a multi-view camera can be calibrated using a large number of incomplete skeletons.

• The Journal of Society for e-Business Studies
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• v.26 no.2
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• pp.123-141
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• 2021

As the dependence of technology on the economic structure increases, the importance of National Core Technology is increasing. However, due to the nature of the technology itself, it is difficult to determine the scope of the technology to be protected because the scope of the relation is abstract and information disclosure is limited due to the nature of the National Core Technology. To solve this problem, we propose the most appropriate literature type and method of analysis to distinguish important technologies related to National Core Technology. We conducted a pilot test to apply TF-IDF, and LDA topic modeling, two techniques of text mining analysis for big data analysis, to four types of literature (news, papers, reports, patents) collected with National Core Technology keywords in the field of Display industry. As a result, applying LDA theme modeling to patent data are highly relevant to National Core Technology. Important technologies related to the front and rear industries of displays, including OLEDs and microLEDs, were identified, and the results were visualized as networks to clarify the scope of important technologies associated with National Core Technology. Throughout this study, we have clarified the ambiguity of the scope of association of technologies and overcome the limited information disclosure characteristics of national core technologies.

• Tunnel and Underground Space
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• v.32 no.6
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• pp.363-372
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• 2022

Precast concrete is an effective method to increase the construction quality and construction speed by optimizing and making the manufacturing conditions similar. In order to more effectively produce a fireproof material-integrated precast duct slab, the purpose of this study was to determine whether the fire resistance performance of the fireproof layer is maintained when a method of increasing the curing rate using a hardening accelerator is used. As a result of performing a fire resistance performance test on specimens classified according to whether or not the hardening accelerator was included, increase of temperature inside the specimen was high in the specimens using the hardening accelerator, and the section loss of the fireproof layer occurred locally on the surface exposed to fire heating. In conclusion, it is judged that the fireproof layer in the case where the strength at 3th day of age is gained within 1 day curing age using a hardening accelerator does not guarantee sufficient fire resistance performance in the conditions used in this study.

• Journal of the Korean Society of Radiology
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• v.17 no.1
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• pp.53-62
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• 2023

The purpose of this study is to find an optimized imaging technique and evaluate its usefulness by comparing and analyzing the difference in contrast enhancement of lower extremity artery according to the patient's heart rate during lower extremity Computed Tomography Angiography examination. From January 2022 to August 22nd, 139 outpatients who visited Ajou University Hospital and underwent lower extremity angio CT examination were targeted. According to the heart rate, the groups were divided into four groups: A(HR ≤65), B(65 < HR < 80), C(80≤ HR). In addition, among patients with a heart rate of 65 or less, the heart rate was considered, and the scan was divided into D, E, F group with a delay time. The time of arrival of contrast medium and the average value of contrast enhancement were compared and analyzed. As a result of quantitative evaluation, B and C groups with a heart rate of more than 65 times had better HU values in the popliteal artery than A group (HR ≤ 65), and D group showed better HU improvement effects compared to A group (p<0.001). The comparative analysis with other groups was insignificant. The difference in heart rate affected the angiographic intensity of the lower extremities artery. Therefore, it is effective to apply the appropriate test timing for each patient by using the heart rate during the lower extremity angio CT Scan.

• Journal of Marine Life Science
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• v.6 no.2
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• pp.47-57
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• 2021

In the fishery industry, global aquaculture production has stagnated due to overfishing of aquatic products, restrictions between countries, and climate change. The aquaculture suggests the possibility of a blue revolution that can be expanded in a new way. The aquaculture industry now accounts for more than half of the fishery products from the sea as a raw material for seafood for human consumption. Various latest biological research methods are being applied for the development of a sustainable aquaculture industry. Genomics has made significant progress in recent years. Since the genome sequence of Atlantic cod was sequenced in 2011, the genomes of more species have been sequenced. The genome information is providing a more robust and productive knowledge base for the aquaculture industry, including breeding and breeding of superior traits, improving disease resistance quality, and optimizing aquaculture feed and feed methods. This review looked at the status of genome analysis technology and the current status of genome research of aquaculture species. The development of genome research technology and massive genomic information is important in solving the challenges of the aquaculture industry and will help sustainable fisheries and aquaculture.

• Composites Research
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• v.35 no.2
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• pp.115-119
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• 2022

The performance of carbon fiber is important for the production of these high-quality polymer composite materials such as CFRP (Carbon Fiber Reinforced Plastic). For this purpose, it is essential to use an optimized spinning process for improving the mechanical, physical, and structural properties of the precursor fiber, which greatly affects the properties of the carbon fiber, and the use of a suitable precursor polymer. In this study, the content of MAA (Methacrylic Acid), MAA injection time, and concentration of AIBN (2,2'-Azobis(2-methylpropionitrile)) were set as parameters for the polymer synthesis process, and Poly(AN-co-MAA) (poly(acrylonitrile-co-methacrylic acid)) was polymerized by solution polymerization. Poly(AN-co-MAA) with a molecular weight of 305,138 g/mol and an MAA ratio of 4.2% was dissolved in DMF (N,N-dimethylformamide) at a concentration of 16.0 wt%, and then a precursor fiber was prepared through dry-jet-wet spinning. The precursor fiber had a tensile strength of ~1.06 GPa and a tensile modulus of ~22.01 GPa, and no voids and structural defects were observed on the fiber.

• Journal of the Korea Organic Resources Recycling Association
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• v.29 no.4
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• pp.47-54
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• 2021

In this study, the performance of a honeycomb-type hydrogen oxidation catalyst to remove hydrogen in a hydrogen economy society to secure leaking hydrogen. The Pd/TiO₂ catalyst was prepared based on a liquid phase reduction method that is not exposed to a heat source, and it was showed through H₂-chemisorption analysis that it existed as very small active particles of 2~4 nm. In addition, it was found that the metal dispersion decreased and the active particle size increased as the reduction reaction temperature increased. It was meant that the active metal particle size and the hydrogen oxidation performance were in a proportional correlation, so that it was consistent with the hydrogen oxidation performance reduction result. The prepared catalyst was coated on a support in the form of a honeycomb so that it could be applied to the hydrogen industrial process. When 20 wt% or more of the AS-40 binder was coated, oxidation performance of 90% or more was observed under low-concentration hydrogen conditions. It was showed through SEM analysis that long-term catalytic activity can be expected by enhancing the adhesion strength of the catalyst and preventing catalyst desorption. It is a basic research that can secure safety in a hydrogen society such as gasification, organic resource, and it can be utilized as a system that can respond to unexpected safety accidents in the future.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.14-14
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• 2023

산업발전에 따른 인구증가, 기후위기에 따른 가뭄 및 물 부족심화, 그리고 수질오염 등은 2015년 제79차 UN총회의 물 안보측면에서 국제사회의 물 분야 위기관리를 위해 2030년을 지속가능한 발전 목표(Sustainable Development Goals)로 하였다. 또한, 현재 물 산업은 빠르게 성장하고 있으며, 2016년 세계경제포럼(World Economic Forum) 의장 클라우스 슈밥(Klaus Schwab)부터 주창된 제4차 산업혁명로 인해 현재 물 산업의 패러다임 또한 급속히 변화하고 있다. 이는 컴퓨터를 기반으로 하는 CPS(Cyber Physical System) 및 DT(Digital Twin) 연계 분석방식의 혁신을 일컫는다. 2002년경에 DT의 기본개념이 제시되었고, 2006년경에는 Embedded System에서의 DT와 같은 개념으로 CPS의 용어가 등장했다. DT는 현실세계에 존재하는 사물, 시스템, 환경 등을 S/W시스템의 가상공간에 동일하게 모사(Virtualization) 및 모의(Simulation)할 수 있도록 하고, 모의결과를 가상시스템으로 현실세계를 최적화 체계 구현 기술을 말한다. DT의 6가지 기능은 ① 실제 데이터(Live Data), ② 모사, ③ 분석정보(Analytics), ④ 모의, ⑤ 예측(Predictions), ⑥ 자동화(Automation) 이다. 또한, CPS는 대규모 센서 및 액추에이터(Actuator)를 가지는 물리적 요소와 이를 실시간으로 제어하는 컴퓨팅 요소가 결합된 복합시스템을 말한다. CPS는 물리세계에서 발생하는 변화를 감지할 수 있는 다양한 센서를 통해 환경인지 기능을 수행한다. 센서로부터 수집된 정보와 물리세계를 재현 및 투영하는 고도화된 시스템 모델들을 기반으로 사이버 물리공간을 인지·분석·예측할 수 있다. CPS의 6가지 구성요소는 ① 상호 운용성(Interoperability), ② 가상화(Virtualization), ③ 분산화(Decentralization), ④ 실시간(Real-time Capability), ⑤ 서비스 오리엔테이션(Service Orientation), ⑥ 모듈화(Modularity)이다. DT와 CPS는 본질적으로 같은 목적, 내용, 그리고 결과를 만들어내고자 하는 같은 종류의 기술이라고 할 수 있다. CPS 및 DT는 물리세계에서 발생하는 변화를 감지할 수 있으며, 토양-지하수 센서를 포함한 관측기술을 통해 환경인지 기능을 수행한다. 지하수 관측기술로부터 수집된 정보와 물리세계를 재현 및 투영하는 고도화된 시스템 모델들을 기반으로 사이버 물리공간 및 디지털 트윈 공간을 인지·분석·예측할 수 있다. CPS 및 DT의 기본 요소들을 실현시키는 것은 양질의 데이터를 모니터링할 수 있는 정확하고 정밀한 1차원 연직 프로파일링 관측기술이며, 이를 토대로 한 수자원 관련 빅데이터의 증가, 빅데이터의 저장과 분석을 가능하게 하는 플랫폼의 개발이다. 본 연구는 CPS 및 DT 기반 토양수분-지하수 관측기술을 이용한 지표수-지하수 연계, 지하수 순환 및 관리, 정수 운영 및 진단프로그램 개발을 위한 토양수분-지하수 관측장치를 지하수 플랫폼 동시성과 디지털 트윈 시뮬레이터 시스템 개발 방향으로 제시하고자 한다.