The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Andrea Marchese - One of the best experts on this subject based on the ideXlab platform.
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residually many bv homeomorphisms map a null set in a set of full measure
Proceedings of The Royal Society A: Mathematical Physical and Engineering Sciences, 2019Co-Authors: Andrea MarcheseAbstract:Let Q = (0,1) 2 be the unit square in R 2 . We prove that in a suitable complete metric space of BV homeomorphisms f : Q → Q with f|@Q = Id, the generical homeomorphism (in the sense of Baire categories) maps a null set in a set of full measure and vice versa. Moreover we observe that, for 1 ≤ p < 2, in the most reasonable complete metric space for such problem, the family of W 1,p homemomorphisms satisfying the above property is of first category, instead.
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residually many bv homeomorphisms map a null set in a set of full measure
arXiv: Functional Analysis, 2015Co-Authors: Andrea MarcheseAbstract:Let $Q=(0,1)^2$ be the unit square in $\mathbb{R}^2$. We prove that in a suitable complete metric space of $BV$ homeomorphisms $f:Q\rightarrow Q$ with $f_{|\partial Q}=Id$, the generical homeomorphism (in the sense of Baire categories) maps a null set in a set of full measure and vice versa. Moreover we observe that, for $1\leq p<2$, in the most reasonable complete metric space for such problem, the family of $W^{1,p}$ homemomorphisms satisfying the above property is of first category, instead.
Chao Wang - One of the best experts on this subject based on the ideXlab platform.
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numerical prediction analysis of the fluctuating pressure and rudder force of full scale hull propeller rudder system
Ocean Engineering, 2018Co-Authors: Chao Wang, X Chang, Liang ZhangAbstract:Abstract In order to analyze the fluctuating pressure and rudder force characteristics of a full-scale hull-propeller-rudder system, a hybrid structured/unstructured grid was combined with the Reynolds-averaged Navier-Stokes (RANS) and volume of fluid (VOF) methods to perform a numerical prediction of model and full-scale performance for the Kriso Container Ship (KCS) case. A numerical simulation for the self-propulsion test of a full-scale ship was first performed to obtain the propeller velocity under the self-propulsion point, the results of which indicated a notable wake fraction and velocity scale effect at the self-propulsion point. Transient two-phase flow calculations were then performed for the model and full-scale KCS hull-propeller-rudder systems. According to the monitoring data, the hull surface fluctuating pressure and rudder force fluctuated periodically over time and the full-scale fluctuating pressure exhibited a higher time-average value as compared to the model-scale pressure. The frequency spectrum curves were also generated by the fast Fourier transform algorithm. The analysis of the frequency spectrum data indicated that the peaks of the fluctuating pressure and rudder force reached their respective maximums at the blade passing frequency (BPF), after which the peak gradually decreased and the full-scale ship reduced more quickly. Furthermore, fluctuating amplitude of full-scale ship was bigger than model-scale.
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numerical prediction analysis of propeller bearing force for full scale hull propeller rudder system
International Journal of Naval Architecture and Ocean Engineering, 2016Co-Authors: Chao Wang, Liang Li, Liyu YeAbstract:Abstract The hybrid grid was adopted and numerical prediction analysis of propeller unsteady bearing force considering free surface was performed for mode and full-scale KCS hull–propeller–rudder system by employing RANS method and VOF model. In order to obtain the propeller velocity under self-propulsion point, firstly, the numerical simulation for self-propulsion test of full-scale ship is carried out. The results show that the scale effect of velocity at self-propulsion point and wake fraction is obvious. Then, the transient two-phase flow calculations are performed for model and full-scale KCS hull–propeller–rudder systems. According to the monitoring data, it is found that the propeller unsteady bearing force is fluctuating periodically over time and full-scale propeller's time-average value is smaller than model-scale's. The frequency spectrum curves are also provided after fast Fourier transform. By analyzing the frequency spectrum data, it is easy to summarize that each component of the propeller bearing force have the same fluctuation frequency and the peak in BFP is maximum. What's more, each component of full-scale bearing force's fluctuation value is bigger than model-scale's except the bending moment coefficient about the Y-axis.
Jacob C. Langer - One of the best experts on this subject based on the ideXlab platform.
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transanal endorectal pull through for hirschsprung disease technique controversies pearls pitfalls and an organized approach to the management of postoperative obstructive symptoms
Seminars in Pediatric Surgery, 2010Co-Authors: Luis De La Torre, Jacob C. LangerAbstract:The transanal endorectal pull-through emerged in the late 1990s as the most recent step in the evolution of the surgical correction of Hirschsprung disease. This operation provides the advantages of a minimal access approach with shorter hospital stay, shorter time to full feeding, less pain, and improved cosmesis with excellent outcomes. This article will review the technical principles of the transanal endorectal pull-through, and will address ongoing controversies in the application of this technique. We will also discuss an organized approach to the problem of obstructive symptoms that may affect a subgroup of patients after the transanal pull-through.
Tao Wang - One of the best experts on this subject based on the ideXlab platform.
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reviewer recommendation for pull requests in github
Information & Software Technology, 2016Co-Authors: Yue Yu, Huaimin Wang, Tao WangAbstract:Context: The pull-based model, widely used in distributed software development, offers an extremely low barrier to entry for potential contributors (anyone can submit of contributions to any project, through pull-requests). Meanwhile, the project's core team must act as guardians of code quality, ensuring that pull-requests are carefully inspected before being merged into the main development line. However, with pull-requests becoming increasingly popular, the need for qualified reviewers also increases. GitHub facilitates this, by enabling the crowd-sourcing of pull-request reviews to a larger community of coders than just the project's core team, as a part of their social coding philosophy. However, having access to more potential reviewers does not necessarily mean that it's easier to find the right ones (the "needle in a haystack" problem). If left unsupervised, this process may result in communication overhead and delayed pull-request processing.Objective: This study aims to investigate whether and how previous approaches used in bug triaging and code review can be adapted to recommending reviewers for pull-requests, and how to improve the recommendation performance.Method: First, we extend three typical approaches used in bug triaging and code review for the new challenge of assigning reviewers to pull-requests. Second, we analyze social relations between contributors and reviewers, and propose a novel approach by mining each project's comment networks (CNs). Finally, we combine the CNs with traditional approaches, and evaluate the effectiveness of all these methods on 84 GitHub projects through both quantitative and qualitative analysis.Results: We find that CN-based recommendation can achieve, by itself, similar performance as the traditional approaches. However, the mixed approaches can achieve significant improvements compared to using either of them independently.Conclusion: Our study confirms that traditional approaches to bug triaging and code review are feasible for pull-request reviewer recommendations on GitHub. Furthermore, their performance can be improved significantly by combining them with information extracted from prior social interactions between developers on GitHub. These results prompt for novel tools to support process automation in social coding platforms, that combine social (e.g., common interests among developers) and technical factors (e.g., developers' expertise).
Y Nemirovsky - One of the best experts on this subject based on the ideXlab platform.
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modeling the pull in parameters of electrostatic actuators with a novel lumped two degrees of freedom pull in model
Sensors and Actuators A-physical, 2002Co-Authors: O Bochobzadegani, Y NemirovskyAbstract:This paper reports a new approach for the direct calculations of the Pull-In parameters of electrostatic actuators using a lumped two degrees of freedom (L2DOF) Pull-In model. This model benefits from shorter calculation time compared with coupled domains finite-elements simulations and from higher accuracy than the L1DOF Pull-In models. Using this model, the variations of the Pull-In with geometry, such as asymmetries in the beams, can be investigated. The L2DOF Pull-In model results are compared with FEM simulations, provided by MEMCAD™, showing excellent agreement. This provides a fast tool for design optimization of actuators with coupled DOF.
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pull in study of an electrostatic torsion microactuator
IEEE\ ASME Journal of Microelectromechanical Systems, 1998Co-Authors: O Degani, Eran Socher, Ariel Lipson, T Lejtner, D J Setter, S Kaldor, Y NemirovskyAbstract:Pull-In study of an electrostatic microactuator is essential for making the electrostatic actuation more effective. In this paper, Pull-In analysis is presented for an electrostatic torsion microactuator. The torsion microactuator can be used as a microtorsion mirror. A polynomial algebraic equation for the Pull-In voltage and Pull-In angle of a torsion microactuator is derived. Two types of microactuators fabricated using bulk micromachining are presented. Measurements done on the fabricated microactuators are reported, showing deviations within 1% error from the calculations.
