GLORIA

GEOMAR Library Ocean Research Information Access

X

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • SAGE Publications  (49)
  • 1
    Online Resource
    Online Resource
    CDMTNet: a novel transfer learning model for the loosening detection of mechanical structures with threaded fasteners
    SAGE Publications ; 2023
    In:  Structural Health Monitoring
    Details
    In: Structural Health Monitoring, SAGE Publications
    Abstract: In mechanical systems, various threaded fasteners are widely used to connect separated components. Loosening occurs frequently due to exposure to harsh working environments, especially vibration environments. Loosening detection can eliminate hidden dangers in advance, and its importance cannot be overemphasized. Ultrasonic detection methods based on machine learning have become popular. However, a proposed machine learning model in a published paper is only suitable for a specific mechanical structure with threaded fasteners; the generality of this type of model is poor. In addition, existing models are well-trained based on abundant labeled data. The labeled data are commonly sparse in practical engineering applications, and it is labor-consuming to obtain these data. This paper presents the creation of a generalized detection model suitable for different threaded connection structures based on transfer learning and the exploitation of a small amount of labeled data for model training and accurate loosening detection. A transfer learning network named the cross-domain matching-mix transfer network (CDMTNet) suitable for different mechanical structures was proposed to transfer the knowledge in a source structure to a target structure. The CDMTNet consists of a feature extraction module, a feature disentangling module, and a classification module. The matching-mix method for data augmentation was proposed to finely train the CDMTNet by exploiting only a small amount of labeled data in the target structure. Two different mechanical structures with threaded fasteners (i.e., a lap joint and a globe-cone joint) were tested in the experiment. Their detection accuracies were both greater than 0.8. The results indicated that our method had wide application potential in engineering.
    Type of Medium: Online Resource
    ISSN: 1475-9217 , 1741-3168
    URL: Article
    DOI: 10.1177/14759217231157069
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2023
    detail.hit.zdb_id: 2101420-6
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 2
    Online Resource
    Online Resource
    Integrating genome-wide association studies and gene expression data highlights dysregulated multiple sclerosis risk pathways
    SAGE Publications ; 2017
    In:  Multiple Sclerosis Journal Vol. 23, No. 2 ( 2017-02), p. 205-212
    Details
    In: Multiple Sclerosis Journal, SAGE Publications, Vol. 23, No. 2 ( 2017-02), p. 205-212
    Abstract: Much effort has been expended on identifying the genetic determinants of multiple sclerosis (MS). Existing large-scale genome-wide association study (GWAS) datasets provide strong support for using pathway and network-based analysis methods to investigate the mechanisms underlying MS. However, no shared genetic pathways have been identified to date. Objective: We hypothesize that shared genetic pathways may indeed exist in different MS-GWAS datasets. Methods: Here, we report results from a three-stage analysis of GWAS and expression datasets. In stage 1, we conducted multiple pathway analyses of two MS-GWAS datasets. In stage 2, we performed a candidate pathway analysis of the large-scale MS-GWAS dataset. In stage 3, we performed a pathway analysis using the dysregulated MS gene list from seven human MS case–control expression datasets. Results: In stage 1, we identified 15 shared pathways. In stage 2, we successfully replicated 14 of these 15 significant pathways. In stage 3, we found that dysregulated MS genes were significantly enriched in 10 of 15 MS risk pathways identified in stages 1 and 2. Conclusion: We report shared genetic pathways in different MS-GWAS datasets and highlight some new MS risk pathways. Our findings provide new insights on the genetic determinants of MS.
    Type of Medium: Online Resource
    ISSN: 1352-4585 , 1477-0970
    URL: Article
    DOI: 10.1177/1352458516649038
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2017
    detail.hit.zdb_id: 2008225-3
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 3
    Online Resource
    Online Resource
    Model decomposition-based optimal formation control for multiple unmanned aerial vehicles
    SAGE Publications ; 2022
    In:  Transactions of the Institute of Measurement and Control Vol. 44, No. 4 ( 2022-02), p. 952-959
    Details
    In: Transactions of the Institute of Measurement and Control, SAGE Publications, Vol. 44, No. 4 ( 2022-02), p. 952-959
    Abstract: This paper deals with the optimal formation control problem based on model decomposition for multiple unmanned aerial vehicles (UAVs). The main contribution of this paper is to integrate the formation control and the trajectory tracking into one unified feedforward control and feedback control framework in an optimal mode. We first establish the dynamic model of the leader-follower UAV formation system, and the communication network topology which only depends on the position information given by the leader. Second, to reduce the complexity of the model, each follower is decomposed into three isolated subsystems. Third, a step-by-step formation controller design scheme decomposed into feedforward control and optimal control of formation control is proposed. Finally, the proposed scheme has been extensively simulated and the results demonstrate the stability and the optimality.
    Type of Medium: Online Resource
    ISSN: 0142-3312 , 1477-0369
    URL: Article
    DOI: 10.1177/01423312211043012
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2022
    detail.hit.zdb_id: 2025882-3
    SSG: 3,2
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 4
    Online Resource
    Online Resource
    Study on the critical loosening condition toward a new design guideline for bolted joints
    SAGE Publications ; 2019
    In:  Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science Vol. 233, No. 9 ( 2019-05), p. 3302-3316
    Details
    In: Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, SAGE Publications, Vol. 233, No. 9 ( 2019-05), p. 3302-3316
    Abstract: An understanding of conditions that trigger the loosening of bolted joints is essential to ensure joint reliability. In this study, a three-dimensional finite element model of a typical bolted joint is developed, and a new simulation method is proposed to quantitatively identify the critical transverse force for initiating loosening. This force is used to evaluate the anti-loosening capacity of bolted joints. Using the proposed simulation method, the effects of factors affecting critical loosening are systematically studied. It is found that the preload, frictional coefficients at the thread and the bearing surfaces, clamped length, and fit tolerance mainly affected loosening. When the preload and friction coefficients are increased, and the clamped length and fit tolerance are reduced, loosening is inhibited. Experiments are performed to demonstrate the reliability of the results. Finally, a suggestion is proposed to improve the design guideline VDI 2230 for bolted joints, which considers the requirement of avoiding loosening under vibrational loading.
    Type of Medium: Online Resource
    ISSN: 0954-4062 , 2041-2983
    URL: Article
    DOI: 10.1177/0954406218802928
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2019
    detail.hit.zdb_id: 2024890-8
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 5
    Online Resource
    Online Resource
    Analysis of Coupled Lateral-Torsional-Pounding Responses of One-Storey Asymmetric Adjacent Structures Subjected to Bi-Directional Ground Motions Part I: Uniform Ground Motion Input
    SAGE Publications ; 2005
    In:  Advances in Structural Engineering Vol. 8, No. 5 ( 2005-10), p. 463-479
    Details
    In: Advances in Structural Engineering, SAGE Publications, Vol. 8, No. 5 ( 2005-10), p. 463-479
    Abstract: This paper presents results of a parametric study of seismic induced lateral-torsional-pounding responses of an asymmetric and a symmetric one-storey system subjected to bi-directional ground motion. The properties of the symmetric model are fixed, while the vibration frequency and eccentricity of the asymmetric model vary in the numerical computation. 20 sets of bi-directional horizontal earthquake ground motion time histories are numerically simulated for the analysis. All the simulated motions are compatible individually with the Newmark-Hall design response spectrum with 5% damping and normalized to 0.5g. Ensemble mean peak responses of the two systems to the 20 sets ground motions are estimated. Both linear elastic and nonlinear inelastic behaviours are studied. Effects of torsional stiffness, structural vibration frequency, eccentricities, and initial gap between two structures are investigated. Numerical results are presented in dimensionless form and compared with the code torsional provisions. In this paper, the input ground motion time histories at all the structural supports are assumed to be uniform. An accompany paper of this study is devoted to discuss the effect of the spatially varying ground motion on coupled lateral-torsional-pounding responses of the adjacent structures (Hao and Gong 2005).
    Type of Medium: Online Resource
    ISSN: 1369-4332 , 2048-4011
    URL: Article
    DOI: 10.1260/136943305774858043
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2005
    detail.hit.zdb_id: 2026561-X
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 6
    Online Resource
    Online Resource
    A soft manipulator for efficient delicate grasping in shallow water: Modeling, control, and real-world experiments
    SAGE Publications ; 2021
    In:  The International Journal of Robotics Research Vol. 40, No. 1 ( 2021-01), p. 449-469
    Details
    In: The International Journal of Robotics Research, SAGE Publications, Vol. 40, No. 1 ( 2021-01), p. 449-469
    Abstract: Collecting in shallow water (water depth: ~30 m) is an emerging field that requires robotics for replacing human divers. Soft robots have several promising features (e.g., safe interaction with the environments, lightweight, etc.) for performing such tasks. In this article, we developed an underwater robotic system with a three-degree-of-freedom (3-DoF) soft manipulator for spatial delicate grasping in shallow water. First, we present the design and fabrication of the soft manipulator with an opposite-bending-and-stretching structure (OBSS). Then, we proposed a simple and efficient kinematics method for controlling the spatial location and trajectory of the soft manipulator’s end effector. The inverse kinematics of the OBSS manipulator can be solved efficiently (computation time: 8.2 ms). According to this inverse kinematics method, we demonstrated that the OBSS soft manipulator could track complex two-dimensional and three-dimensional trajectories, including star, helix, etc. Further, we performed real-time closed-loop pick-and-place experiments of the manipulator with binocular and on-hand cameras in a lab aquarium. Hydrodynamic experiments showed that the OBSS soft manipulator produced little force (less than 0.459 N) and torque (less than 0.228 N·m), which suggested its low-inertia feature during the underwater operation. Finally, we demonstrated that the underwater robotic system with the OBSS soft manipulator successfully collected seafood animals at the bottom of the natural oceanic environment. The robot successfully collected eight sea echini and one sea cucumber within 20 minutes at a water depth of around 10 m.
    Type of Medium: Online Resource
    ISSN: 0278-3649 , 1741-3176
    URL: Article
    DOI: 10.1177/0278364920917203
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2021
    detail.hit.zdb_id: 2015221-8
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 7
    Online Resource
    Online Resource
    Mapping the youth soccer: A bibliometrix analysis using R-tool
    SAGE Publications ; 2023
    In:  DIGITAL HEALTH Vol. 9 ( 2023-01)
    Details
    In: DIGITAL HEALTH, SAGE Publications, Vol. 9 ( 2023-01)
    Abstract: In recent years, there has been an increase in the scientific production of youth soccer. However, a panoramic map of research on this subject does not exist. The aim of this study was to identify global research trends in youth soccer over time, among the main levels of analysis: sources, authors, documents, and keywords. The bibliometric software Biblioshiny was used to analyze 2606 articles in Web of Science (WoS) published between 2012 and 2021. The main conclusion is that US and UK scholars dominate the research; the topics of research are changing with the real needs, and research on the topic of performance has been of interest to scholars; talent identification and development, performance, injury prevention, and concussion are the studies of interest to scholars in this area. This finding, which offers a global picture of youth soccer research over time, can help future research in this or similar domains.
    Type of Medium: Online Resource
    ISSN: 2055-2076 , 2055-2076
    URL: Article
    DOI: 10.1177/20552076231183550
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2023
    detail.hit.zdb_id: 2819396-9
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 8
    Online Resource
    Online Resource
    Ultrasound Image Edge Detection Based on a Novel Multiplicative Gradient and Canny Operator
    SAGE Publications ; 2015
    In:  Ultrasonic Imaging Vol. 37, No. 3 ( 2015-07), p. 238-250
    Details
    In: Ultrasonic Imaging, SAGE Publications, Vol. 37, No. 3 ( 2015-07), p. 238-250
    Abstract: To achieve the fast and accurate segmentation of ultrasound image, a novel edge detection method for speckle noised ultrasound images was proposed, which was based on the traditional Canny and a novel multiplicative gradient operator. The proposed technique combines a new multiplicative gradient operator of non-Newtonian type with the traditional Canny operator to generate the initial edge map, which is subsequently optimized by the following edge tracing step. To verify the proposed method, we compared it with several other edge detection methods that had good robustness to noise, with experiments on the simulated and in vivo medical ultrasound image. Experimental results showed that the proposed algorithm has higher speed for real-time processing, and the edge detection accuracy could be 75% or more. Thus, the proposed method is very suitable for fast and accurate edge detection of medical ultrasound images.
    Type of Medium: Online Resource
    ISSN: 0161-7346 , 1096-0910
    URL: Article
    DOI: 10.1177/0161734614554461
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2015
    detail.hit.zdb_id: 2012028-X
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 9
    Online Resource
    Online Resource
    Calculation of the effective bearing contact radius for precision tightening of bolted joints
    SAGE Publications ; 2016
    In:  Advances in Mechanical Engineering Vol. 8, No. 9 ( 2016-09), p. 168781401666844-
    Details
    In: Advances in Mechanical Engineering, SAGE Publications, Vol. 8, No. 9 ( 2016-09), p. 168781401666844-
    Abstract: Torque control is usually the only method for tightening bolts in some precision assembly applications. However, the scatter of the torque–tension relationship may significantly decrease the accuracy of the preload, which conflicts with the high requirement for mechanical accuracy in such precision assemblies. An important, but often ignored, factor affecting the accuracy of the torque–tension relationship is the effective bearing contact radius. In this article, a three-dimensional finite element model of a typical bolted joint was developed to obtain the actual bearing pressure distribution, based on which the effective bearing contact radius can be further calculated. Then, a parametrical study was conducted to systematically investigate the effects of various geometrical, material, and frictional factors on the effective bearing contact radius. Based on the numerical results, a comprehensive and quantitative evaluation of the relative accuracy of each traditional method of calculating the effective bearing contact radius was made. In particular, it was found that the effective bearing contact radius, calculated based on the assumption of uniform bearing pressure distribution, was always relatively accurate regardless of the geometrical, material, and frictional conditions considered. This study will be helpful in increasing the accuracy of preload, thus ensuring mechanical accuracy and quality for precision assemblies.
    Type of Medium: Online Resource
    ISSN: 1687-8140 , 1687-8140
    URL: Article
    DOI: 10.1177/1687814016668445
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2016
    detail.hit.zdb_id: 2501620-9
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 10
    Online Resource
    Online Resource
    A multi-perforation staged fracturing experimental study on hydraulic fracture initiation and propagation
    SAGE Publications ; 2020
    In:  Energy Exploration & Exploitation Vol. 38, No. 6 ( 2020-11), p. 2466-2484
    Details
    In: Energy Exploration & Exploitation, SAGE Publications, Vol. 38, No. 6 ( 2020-11), p. 2466-2484
    Abstract: Hydraulic fracture initiation and propagation are extremely important on deciding the production capacity and are crucial for oil and gas exploration and development. Based on a self-designed system, multi-perforation cluster-staged fracturing in thick tight sandstone reservoir was simulated in the laboratory. Moreover, the technology of staged fracturing during casing completion was achieved by using a preformed perforated wellbore. Three hydraulic fracturing methods, including single-perforation cluster fracturing, multi-perforation cluster conventional fracturing and multi-perforation cluster staged fracturing, were applied and studied, respectively. The results clearly indicate that the hydraulic fractures resulting from single-perforation cluster fracturing are relatively simple, which is difficult to form fracture network. In contrast, multi-perforation cluster-staged fracturing has more probability to produce complex fractures including major fracture and its branched fractures, especially in heterogeneous samples. Furthermore, the propagation direction of hydraulic fractures tends to change in heterogeneous samples, which is more likely to form a multi-directional hydraulic fracture network. The fracture area is greatly increased when the perforation cluster density increases in multi-perforation cluster conventional fracturing and multi-perforation cluster-staged fracturing. Moreover, higher perforation cluster densities and larger stage numbers are beneficial to hydraulic fracture initiation. The breakdown pressure in homogeneous samples is much higher than that in heterogeneous samples during hydraulic fracturing. In addition, the time of first fracture initiation has the trend that the shorter the initiation time is, the higher the breakdown pressure is. The results of this study provide meaningful suggestions for enhancing the production mechanism of multi-perforation cluster staged fracturing.
    Type of Medium: Online Resource
    ISSN: 0144-5987 , 2048-4054
    URL: Article
    DOI: 10.1177/0144598720914991
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2020
    detail.hit.zdb_id: 2026571-2
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...