• 제목/요약/키워드: fundamental research

검색결과 4,459건 처리시간 0.033초

Imbalanced sample fault diagnosis method for rotating machinery in nuclear power plants based on deep convolutional conditional generative adversarial network

  • Zhichao Wang;Hong Xia;Jiyu Zhang;Bo Yang;Wenzhe Yin
    • Nuclear Engineering and Technology
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    • 제55권6호
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    • pp.2096-2106
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    • 2023
  • Rotating machinery is widely applied in important equipment of nuclear power plants (NPPs), such as pumps and valves. The research on intelligent fault diagnosis of rotating machinery is crucial to ensure the safe operation of related equipment in NPPs. However, in practical applications, data-driven fault diagnosis faces the problem of small and imbalanced samples, resulting in low model training efficiency and poor generalization performance. Therefore, a deep convolutional conditional generative adversarial network (DCCGAN) is constructed to mitigate the impact of imbalanced samples on fault diagnosis. First, a conditional generative adversarial model is designed based on convolutional neural networks to effectively augment imbalanced samples. The original sample features can be effectively extracted by the model based on conditional generative adversarial strategy and appropriate number of filters. In addition, high-quality generated samples are ensured through the visualization of model training process and samples features. Then, a deep convolutional neural network (DCNN) is designed to extract features of mixed samples and implement intelligent fault diagnosis. Finally, based on multi-fault experimental data of motor and bearing, the performance of DCCGAN model for data augmentation and intelligent fault diagnosis is verified. The proposed method effectively alleviates the problem of imbalanced samples, and shows its application value in intelligent fault diagnosis of actual NPPs.

Production of Arachidonic Acid by Mortierella Fungi

  • Higashiyama, Kenichi;Fujikawa, Shigeaki;Park, Enoch Y.;Shimizu , Sakazu
    • Biotechnology and Bioprocess Engineering:BBE
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    • 제7권5호
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    • pp.252-262
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    • 2002
  • The growing interest in the application of arachidonic acid (ARA) in various fields of health and dietary requirements has elicited much attention on the industrial production of ARA-containing oil by the cultivation of Mortierella fungi. For the industrial production of ARA, various studies, such as isolation of a high-potential strain and optimization of culture conditions, have been conducted. Studies including the investigation of morphology are important because ARA is accumulated in the mycelia, and thus cultivation with high biomass concentration is essential for obtaining a high ARA yield. Combining the results derived from various studies, a high ARA yield was attained in an industrial fermentor. These ARA production techniques are applicable to the production of other polyunsaturated fatty acids (PUFAs), and will contribute to the improvement of fermentation technology especially in the field of fungal cultivation.

Nonlinear dynamic FE analysis of structures consisting of rigid and deformable parts -Part II - Computer implementation and test examples

  • Rojek, J.;Kleiber, M.
    • Structural Engineering and Mechanics
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    • 제2권4호
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    • pp.327-343
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    • 1994
  • This is the second part of the paper (Rojek and Kleiber 1993) devoted to nonlinear dynamic analysis of structures consisting of rigid and deformable parts. The first part contains a theoretical formulation of nonlinear equations of motion for the coupled system as well as a solution algorithm. The second part presents the computer implementation of the equations derived in the first part with a short review of the capabilities of the computer program used and the library of finite elements. Details of material nonlinearity treatment are also given. The paper is illustrated by discussing a practical problem of a safety cab analysis for an agricultural tractor.

Nonlinear dynamic FE analysis of structures consisting of rigid and deformable parts -Part I - Formulation

  • Rojek, J.;Kleiber, M.
    • Structural Engineering and Mechanics
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    • 제2권4호
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    • pp.313-326
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    • 1994
  • Some structures under the action of some specific loads can be treated as consisting of rigid and deformable parts. The paper presents a way to include rigid elements into a finite element model accounting for geometrical and material nonlinearities. Lagrange multipliers technique is used to derive equations of motion for the coupled deformable-rigid system. Solution algorithm based on the elimination of the Lagrangian multipliers and dependent kinematic unknowns at the element level is described. A follow-up paper(Rojek and Kleiber 1993) complements the discussion by giving details of the computer implementation and presenting some realistic test examples.

공공기관에서의 지식관리시스템 수용의 영향요인과 저항의 조절효과 (Factors Accepting KMS and the Moderating Role of Resistance in Public Sector)

  • 박동진;배동록
    • 한국정보시스템학회지:정보시스템연구
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    • 제17권2호
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    • pp.73-94
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    • 2008
  • Knowledge is a fundamental assets, therefore, the ability to create, acquire, integrate, and share knowledge has emerged as a fundamental organizational capability(Sambamurthy and Subramani, 2005). This apaper reports the results of an empirical study investigating the factors of acceptance and the moderating role of resistance in Knowledge Management Systems(KMS). The research model is based on the theory of planned behavior(TPB) and technology acceptance model(TAM). It includes the perceived usefulness instead of attitude, subjective norm, perceived behavior control and intention of acceptance of KMS. Also, three external variables namely task-technology fit, organizational support, and perceived rewards are added. In the research model, all hypothrses of the baseline model and the moderating effects of resistance were found to be significant. The authors also of fred several implications based chi the findings.

저융점 개질유황의 산화마그네슘 치환에 따른 모르타르의 역학적 특성 (The Mechanical Property of Mortar According to the MgO Replacement of Low Melting Modified Sulfur)

  • 정병열;문지환;이상수;송하영
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2012년도 추계 학술논문 발표대회
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    • pp.97-98
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    • 2012
  • This research examined the fundamental property of the MgO as the fundamental study that substituted the MgO in the low melting point modified sulfur mortar to examine the physical properties.In this research, the table floor, flexural strength test, and compressive strength test were performed. And as the replacement ratio increased, the floor showed the tendency to increase. And when being the replacement ratio 3%, the flexural strength and compressive strength made the high strength. In case of being substituted for over 5% they displayed the tendency that the intensity is degraded.

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실리카 흄을 혼입한 고강도 콘크리트의 시공성 및 공학적 특성에 관한 기초적 연구 (A Fundamental Study on the Workability and Engineering Properties of Silica-Fume High Strength Concrete)

  • 권영진;김무한
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 1990년도 봄 학술발표회 논문집
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    • pp.29-34
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    • 1990
  • Energy cries and availability have funded extensive research and numerous conferences. So, the idea of adding slags and pozzolans such as flyash to portland cement or portland cement concrete is widely practiced because it helps to reduce cost and conserve energy, resources and the environment. Recently, Silicafume which is the industrial by-product of electric arc furnaces is also widely studied for achieving high strength concrete. It is the aim of this study to provide the fundamental data on the workability and engineering proper of high strength concrete containing flyash and silica fume comparing with plain concrete for the practical use and research data accumulation of a new technique for achieving high strength concrete.

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소형 모형선을 이용한 실선마력추정에 대한 연구 (A Fundamental Study on the Power Prediction Method of Ship by using the Experiment of Small Model)

  • 하윤진;이영길
    • 대한조선학회논문집
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    • 제51권3호
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    • pp.231-238
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    • 2014
  • In this study, the self-propulsion tests are performed in INHA towing tank. And the effective wake characteristics of the KVLCC2 and the KCS models are compared by the experimental results. The form factor is independent of Reynolds number. To estimate the hydrodynamic performance of a full scale ship, the form factor is determined to consider attendant on Reynolds number. In this research, the power predictions are carried out considering the form factor difference of model and full scale ship. The results of this research could be used as one of the fundamental data to the powering performance prediction.

Physical, mechanical and hydraulic properties of Inada granite and Shirahama sandstone in Japan

  • Zhang Ming;Takeda Mikio
    • 한국지구물리탐사학회:학술대회논문집
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    • 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
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    • pp.206-213
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    • 2003
  • Laboratory testing of representative rock specimens is of fundamental necessity for the successful design and/or assessment of facilities associated with many kinds of underground exploitation, including the geological disposal of radioactive nuclear waste. As a fundamental and systematic study, a series of measurements of the physical, mechanical and hydraulic properties of Inada granite and Shirahama sandstone, two rock types that are widely available in Japan, have been performed. This paper presents the results of a study of the effective porosity, density, compressive and shear wave velocity, unconfined compressive strength and permeability of the two rocks. The anisotropy and the effects of confining pressure on the permeability of the rocks, as well as the relationships among the physical, mechanical and hydraulic properties, are also investigated and discussed.

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Genome of Bifidobacteria and Carbohydrate Metabolism

  • Bondue, Pauline;Delcenserie, Veronique
    • 한국축산식품학회지
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    • 제35권1호
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    • pp.1-9
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    • 2015
  • In recent years, the knowledge about bifidobacteria has considerably evolved thanks to recent progress in molecular biology. The analysis of the whole genome sequences of 48 taxa of bifidobacteria offers new perspectives for their classification, especially to set up limit between two species. Indeed, several species are presenting a high homology and should be reclassified. On the other hand, some subspecies are presenting a low homology and should therefore be reclassified into different species. In addition, a better knowledge of the genome of bifidobacteria allows a better understanding of the mechanisms involved in complex carbohydrate metabolism. The genome of some species of bifidobacteria from human but also from animal origin demonstrates high presence in genes involved in the metabolism of complex oligosaccharides. Those species should be further tested to confirm their potential to metabolize complex oligosaccharides in vitro and in vivo.