• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.967-974
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• 2022

It is no news that Nigeria's infrastructure challenge is enormous. In the global ranking, Nigeria ranked low in quantity and quality of its infrastructural provision which has a great impact on the ease of business transaction. Low investments in transportation have brought about the current infrastructural deficit. Recently, the Nigerian government has made effort to address at least to some extent the infrastructural deficit through Public-Private Partnership, but this has not yielded the desired result. Moreover, the sustainability issues relating to railway projects such as, emissions, noise pollution, ecosystem, and other environmental issues calls for urgent attention. Hence, this necessitated consideration on sustainability appraisal for the Chinese rail project in Nigeria. This study reviews sustainability of railway projects built by the Chinese firm in Nigeria with particular emphasis on the environmental and social impact of these projects. The study further identified issues and challenges in project implementation with a particular focus on civil dialogue and community engagements. A detailed literature search was conducted on railway projects and infrastructure by systematically reviewing selected published articles.The analysis of the selected articles identified sustainability issues and potential for improvement of Chinese railway projects and how they contribute to or inhibit competitiveness in the Nigerian railway market. From the literature searched, some of the projects constructed by Chinese firm revealed that there is economic and social impact of railway projects delivered by the Chinese firm in terms of capacity development and knowledge transfer potentiality. For instance, in the just concluded Lagos-Ibadan railway projects, the study gathered that the project brought about 5000 jobs and local staff were trained by the Chinese company, this will boost man power and local content capability. Also, it will significantly improve Nigeria's infrastructure and boost its economic development. The study suggests that Nigerian government should ensure and provide an enabling environment that is conducive for investment on the continent. Peace, improved security, and decent governance are the best conditions for sustainable transportation growth.

• 한국산업융합학회 논문집
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• 제26권6_3호
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• pp.1297-1303
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• 2023

Research on enhancing the mechanical strength, lightweight properties, electrical conductivity, and thermal conductivity of composite materials by incorporating nano-materials is actively underway. Thermoplastic resins can change their form under heat, making them highly processable and recyclable. In this study, Polyamide-Nylon 6 (PA6), a thermoplastic resin, was utilized, and as reinforcing agents, fused carbon nano-materials (FCN) formed by structurally combining Carbon Nanotube(CNT) and Graphene were employed. Nano-materials often face challenges related to cohesion and dispersion. To address this issue, Silane functional groups were introduced to enhance the dispersion of FCN in PA6. The manufacturing conditions for the composite materials involved determining the use of a dispersant and varying FCN content at 0.05 wt%, 0.1 wt%, and 0.2 wt%. Tensile strength measurements were conducted, and FE-SEM analysis was performed on fracture surfaces. As a result of the tensile strength test, it was confirmed that compared to pure PA6, the strength of the polymer composite with a content of 0.05 wt% was improved by about 60%, for 0.1 wt%, about 65%, and for 0.2 wt%, the strength was improved by 50%. Also, when compared according to the content of FCN, the best strength value was shown when 0.1 wt% was added. The elastic modulus also showed an improvement of about 15% in the case of surface treatment compared to the case without surface treatment, and an improvement of about 70% compared to pure PA6. Through FE-SEM, it was confirmed that the matrix material and silane-modified nanomaterial improved the dispersibility and bonding strength of the interface, helping to support the load evenly and enabling effective stress transfer.

• 한국전기전자재료학회논문지
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• 제37권3호
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• pp.261-273
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• 2024

This paper is an experimental study on the improvement of smoke and flame detection from different materials with YOLO. For the study, images of fires occurring in various materials were collected through an open dataset, and experiments were conducted by changing the main factors affecting the performance of the fire object detection model, such as the bounding box, polygon, and data augmentation of the collected image open dataset during data preprocessing. To evaluate the model performance, we calculated the values of precision, recall, F1Score, mAP, and FPS for each condition, and compared the performance of each model based on these values. We also analyzed the changes in model performance due to the data preprocessing method to derive the conditions that have the greatest impact on improving the performance of the fire object detection model. The experimental results showed that for the fire object detection model using the YOLOv5s6.0 model, data augmentation that can change the color of the flame, such as saturation, brightness, and exposure, is most effective in improving the performance of the fire object detection model. The real-time fire object detection model developed in this study can be applied to equipment such as existing CCTV, and it is believed that it can contribute to minimizing fire damage by enabling early detection of fires occurring in various materials.

• Tribology and Lubricants
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• 제40권1호
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• pp.17-23
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• 2024

This study analyzes the thermal effects on the performance of an air foil thrust bearing (AFTB) using COMSOL Multiphysics to approximate actual bearing behavior under real conditions. An AFTB is a sliding-thrust bearing that uses air as a lubricant to support the axial load. The AFTB consists of top and bump foils and supports the rotating disk through the hydrodynamic pressure generated by the wedge effect from the inclined surface of the top foil and the elastic deformation of the bump foils, similar to a spring. The use of air as a lubricant has some advantages such as low friction loss and less heat generation, enabling air bearings to be widely used in high-speed rotating systems. However, even in AFTB, the effects of energy loss due to viscosity at high speeds, interface frictional heat, and thermal deformation of the foil caused by temperature increase cannot be ignored. Foil deformation derived from the thermal effect influences the minimum decay in film thickness and enhances the film pressure. For these reasons, performance analyses of isothermal AFTBs have shown few discrepancies with real bearing behavior. To account for this phenomenon, a thermal-fluid-structure analysis is conducted to describe the combined mechanics. Results show that the load capacity under the thermal effect is slightly higher than that obtained from isothermal analysis. In addition, the push and pull effects on the top foil and bump foil-free edges can be simulated. The differences between the isothermal and thermal behaviors are discussed.

• 한국전자통신학회논문지
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• 제19권1호
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• pp.301-307
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• 2024

본 연구는 다양한 스케일 조건에서 열화상 이미지를 향상시키기 위한 새로운 캐스케이드 융합 구조를 제안한다. 특정 스케일에 맞춰 설계된 방법들은 다중 스케일에서 열화상 이미지 처리에 한계가 있었다. 이를 극복하기 위해 본 논문에서는 다중 스케일 표현을 활용하는 캐스케이드 특징 융합 기법에 기반한 통합 프레임워크를 제시한다. 서로 다른 스케일의 신뢰도 맵을 순차적으로 융합함으로써 스케일에 제약받지 않는 학습이 가능해진다. 제안된 구조는 상호 스케일 의존성을 강화하기 위해 엔드 투 엔드 방식으로 훈련된 합성곱 신경망으로 구성되어 있다. 실험 결과, 제안된 방법은 기존의 다중 스케일 열화상 이미지 향상 방법들보다 우수한 성능을 보인다는 것을 확인할 수 있었다. 또한, 실험 데이터셋에 대한 성능 분석 결과 이미지 품질 지표가 일관되게 개선되었으며, 이는 캐스케이드 융합 설계가 스케일 간 견고한 일반화를 가능하게 하고 교차 스케일 표현 학습을 더 효율적으로 수행하는 데 기여하는 것을 보여준다.

• 한국전자통신학회논문지
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• 제19권3호
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• pp.577-582
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• 2024

국내 펫 보험은 2007년 첫 도입되어 현재 2024년 지금까지 많은 보험상품들이 생겼고 펫 보험 시장은 매년 증가하고 있는 추세이다. 하지만 실상은 2022년 기준 펫 보험 가입률은 전체 반려인의 0.8%이며 반려인들은 비싼 보험료 및 보장내역, 까다로운 가입 기준으로 인해 펫 보험 가입을 꺼리고 있다. 본 논문에서는 반려동물 안구질환 및 질환의 위치를 인식하고 건강나이를 예측 가능한 모델링을 제안한다. 먼저 EfficientNet을 활용해 반려동물의 안구질환을 인식하고 OpenCV를 활용 질환의 발병 위치와 크기를 인식하여 반려동물의 건강나이를 산출한다. 산출된 해당 건강나이를 바탕으로 보험사에서 펫 보험료 산정 시 보조하는 역할을 하고자 한다. 이 모델링은 반려동물 안구질환 및 건강나이로 합리적인 펫 보험 가격 산정 보조가 가능하다.

• Advances in nano research
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• 제16권6호
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• pp.623-638
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• 2024

This study investigates the thermal post-buckling behavior of concrete eccentric annular sector plates reinforced with graphene oxide powders (GOPs). Employing the minimum total potential energy principle, the plates' stability and response under thermal loads are analyzed. The Haber-Schaim foundation model is utilized to account for the support conditions, while the transform differential quadrature method (TDQM) is applied to solve the governing differential equations efficiently. The integration of GOPs significantly enhances the mechanical properties and stability of the plates, making them suitable for advanced engineering applications. Numerical results demonstrate the critical thermal loads and post-buckling paths, providing valuable insights into the design and optimization of such reinforced structures. This study presents a machine learning algorithm designed to predict complex engineering phenomena using datasets derived from presented mathematical modeling. By leveraging advanced data analytics and machine learning techniques, the algorithm effectively captures and learns intricate patterns from the mathematical models, providing accurate and efficient predictions. The methodology involves generating comprehensive datasets from mathematical simulations, which are then used to train the machine learning model. The trained model is capable of predicting various engineering outcomes, such as stress, strain, and thermal responses, with high precision. This approach significantly reduces the computational time and resources required for traditional simulations, enabling rapid and reliable analysis. This comprehensive approach offers a robust framework for predicting the thermal post-buckling behavior of reinforced concrete plates, contributing to the development of resilient and efficient structural components in civil engineering.

• 한국BIM학회 논문집
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• 제14권2호
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• pp.25-34
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• 2024

This study proposes a new methodology to increase the flexibility and efficiency of the design data evaluation system by combining Building Information Modeling (BIM) technology in the architectural industry, OpenAI's interactive artificial intelligence, and ChatGPT. BIM technology plays an important role in digitally modeling and managing architectural information. Since architectural information is included, research and development are underway to review and evaluate BIM data according to conditions through program development. However, in the process of reviewing BIM design data, if the review criteria or evaluation criteria according to design change occur frequently, it is necessary to update the program anew. In order for designers or reviewers to apply the changed criteria, requesting a program developer will delay time. This problem was studied by using ChatGPT to modify and update the design data evaluation program code in real time. In this study, it is aimed to improve the changing standards and accuracy by enabling programming non-professionals to change the design regulations and calculation standards of the BIM evaluation program system using ChatGPT. In this study, in the BIM-based design certification automation evaluation program, a program in which the automation evaluation method is being studied based on the design certification evaluation manual was first used. In the design certification automation evaluation program, the programming non-majors checked the automation evaluation code by linking ChatGPT, and the changed calculation criteria were created and modified interactively. As a result of the evaluation, the change in the calculation standard was explained to ChatGPT and the applied result was confirmed.

• 한국지반공학회논문집
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• 제40권4호
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• pp.105-112
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• 2024

지구온난화로 인한 기후변화로 예측 불가능한 집중호우가 증가하여 국내 하천의 홍수 피해는 심각해지고 있으며 이에 따라 수중보의 제체 및 기초지반을 통한 침투량 증가는 파이핑 현상을 유발하여 수중보의 안정성을 위협한다. 따라서 수중보의 관리와 설계에 있어 증가하는 침투유량에 관한 많은 연구가 필요하다. 본 연구에서는 수중보에 대하여 투수층의 깊이와 널말뚝 길이 및 위치를 달리하여 수치해석과 단면분할법 및 Polubarinova-Kochina가 제안한 방법을 사용하여 침투유량을 산정하고 비교 분석하였다. 그 결과 침투유량은 S/T가 증가함에 따라 감소하였고, X/b가 증가할수록 증가하는 경향을 보였으며 널말뚝 위치에 대한 차이보다는 널말뚝 길이의 변화가 침투유량에 더 많은 영향을 끼치는 것으로 판단되었다. 따라서, 수중보 설계 시 지층깊이를 고려한 긴 널말뚝을 적용하고 제체의 상류부에 설치할수록 침투유량이 감소해 파이핑에 대해 안전한 설계가 가능할 것으로 판단된다.

• 한국환경복원기술학회지
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• 제6권4호
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• pp.62-73
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• 2003

The study was to apply a mat style reed planting method at confluence to improve plants growth conditions by relaxing disturbed topographical base due to water flow and was intended to review the effect to build up a vegetation strip by monitoring process after the construction. First off, We've attempted to construct reed mats on selected sites as confluences of Tan and Gaehwa stream and then examined and analyzed characteristics of soil and vegetation community. As the results of the examination, the soil texture was proven to be a mix of sand and loamy sand and be 6.3 ~ 7.0 soil pH. In addition, it contained 1.0 ~ 4.6% of organic matter, 0.04 ~ 0.22% of T-N and 27.8 ~ 41.2% of water content. For its vegetation structure, the Tan stream confluence was first actually a point bar without plants prior to the construction but 8 kinds of hygrophytes including Persicaria hydropiper and 9 kinds of terrestrial plants such as Potentilla supina, Artemisia annua, and Alopecurus aequalis var. amurensis. On the other hand, the Gaehwa stream confluence contained 6 kinds of hygrophytes such as Bidens frondosa and other 11 kinds of terrestrial plants prior to the construction while it produced 7 kinds of hygrophytes including Ranunculus ternatus as well as Phragmites australis and 9 kinds of terrestrial plants such as Potentilla supina after the construction. For the Phragmites australis, almost of them was weathered away in early days just after planting because of development period passed, but on May, six months later from planting, it was investigated that its length was approximated as 65 ~ 85cm with 75% coverage and that the number of it was 437 ~ 633/$m^2$. The study was shown that reed mats can improve environmental conditions of disturbed topographical base, enabling natural growth of various riparian vegetation including the introduced plant, reed. In the meantime, it was supposedly judged that to recover or build up a vegetarian strip, supplementary materials should be prepared to help produce and grow plants because it is not probable to expect river drift by water flow at confluence and that corrosion, burying or inundation owing to changes of water lever should be considered.