Concentration Gradient‐Based Soft Robotics: Hydrogels Out of Water

Concentration gradient in a chamber appended to a microchannel is important to cell movement control and to the concentration gradient based assays on Lab-on-a-Chip devises. In this paper, the effects on the concentration field of the asymmetrical injection, the Peclet number, the mobility ratio of electrophoresis to electroosmosis, the chamber’s downstream position, and the chamber’s geometry parameters, are investigated. The most sensitive parameter is the asymmetrical injection, which can increase the concentration gradient twice as large as to that in the symmetrical injection. Furthermore, using heterogeneous surface patches is a very effective way to enhance the concentration gradient generated in the chamber. Different patches for certain chambers are investigated. Finally, experimental visualization of the concentration fields was conducted, and good agreements were found between the numerical simulation results and the experimental results of the concentration fields generated in a micro-chamber with/without a heterogeneous patch.

Download Full-text

Rayleigh-Taylor Instability in a Phase Separating Mixture under a Concentration Gradient

Journal de Physique II ◽

10.1051/jp2:1995230 ◽

1995 ◽

Vol 5 (7) ◽

pp. 1067-1076 ◽

Cited By ~ 1

Author(s):

Y. Jayalakshmi ◽

D. Beysens

Keyword(s):

Concentration Gradient ◽

Taylor Instability ◽

Rayleigh Taylor Instability

Download Full-text

Gradient based system-level diagnosis

Periodica Polytechnica Electrical Engineering ◽

10.3311/pp.ee.2007-1-2.05 ◽

2007 ◽

Vol 51 (1-2) ◽

pp. 43

Author(s):

Balázs Polgár ◽

Endre Selényi

Keyword(s):

System Level ◽

Gradient Based

Download Full-text

An Efficient Multiple Description Coding for Multi-View Video Based on the Correlation of Spatial Polyphase Transformed Subsequences

Journal of Imaging Science and Technology ◽

10.2352/j.imagingsci.technol.2019.63.5.050401 ◽

2019 ◽

Vol 63 (5) ◽

pp. 50401-1-50401-7 ◽

Cited By ~ 1

Author(s):

Jing Chen ◽

Jie Liao ◽

Huanqiang Zeng ◽

Canhui Cai ◽

Kai-Kuang Ma

Keyword(s):

Video Transmission ◽

Video Sequence ◽

Three Dimensional ◽

The Other ◽

Multiple Description Coding ◽

Multiple Description ◽

Prediction Mode ◽

Gradient Based ◽

Directional Interpolation ◽

Description Coding

Abstract For a robust three-dimensional video transmission through error prone channels, an efficient multiple description coding for multi-view video based on the correlation of spatial polyphase transformed subsequences (CSPT_MDC_MVC) is proposed in this article. The input multi-view video sequence is first separated into four subsequences by spatial polyphase transform and then grouped into two descriptions. With the correlation of macroblocks in corresponding subsequence positions, these subsequences should not be coded in completely the same way. In each description, one subsequence is directly coded by the Joint Multi-view Video Coding (JMVC) encoder and the other subsequence is classified into four sets. According to the classification, the indirectly coding subsequence selectively employed the prediction mode and the prediction vector of the counter directly coding subsequence, which reduces the bitrate consumption and the coding complexity of multiple description coding for multi-view video. On the decoder side, the gradient-based directional interpolation is employed to improve the side reconstructed quality. The effectiveness and robustness of the proposed algorithm is verified by experiments in the JMVC coding platform.

Download Full-text

Stable and Supported Semantics in Continuous Vector Spaces

Proceedings of the Seventeenth International Conference on Principles of Knowledge Representation and Reasoning ◽

10.24963/kr.2020/7 ◽

2020 ◽

Author(s):

Yaniv Aspis ◽

Krysia Broda ◽

Alessandra Russo ◽

Jorge Lobo

Keyword(s):

Logic Program ◽

Matrix Multiplication ◽

Vector Spaces ◽

Continuous Space ◽

Continuous Vector ◽

Novel Approach ◽

Gradient Based ◽

Normal Logic ◽

Parameter Values ◽

Normal Logic Program

We introduce a novel approach for the computation of stable and supported models of normal logic programs in continuous vector spaces by a gradient-based search method. Specifically, the application of the immediate consequence operator of a program reduct can be computed in a vector space. To do this, Herbrand interpretations of a propositional program are embedded as 0-1 vectors in $\mathbb{R}^N$ and program reducts are represented as matrices in $\mathbb{R}^{N \times N}$. Using these representations we prove that the underlying semantics of a normal logic program is captured through matrix multiplication and a differentiable operation. As supported and stable models of a normal logic program can now be seen as fixed points in a continuous space, non-monotonic deduction can be performed using an optimisation process such as Newton's method. We report the results of several experiments using synthetically generated programs that demonstrate the feasibility of the approach and highlight how different parameter values can affect the behaviour of the system.

Download Full-text

Stiffness-gradient-based Grasping Force Control for an Underactuated Prosthetic Hand

Recent Advances in Electrical & Electronic Engineering (Formerly Recent Patents on Electrical & Electronic Engineering) ◽

10.2174/2352096511666180213113017 ◽

2018 ◽

Vol 11 (4) ◽

pp. 460-464

Author(s):

Yi Zhang ◽

Hua Deng ◽

Wendi Zhuo ◽

Guoliang Zhong

Keyword(s):

Force Control ◽

Prosthetic Hand ◽

Grasping Force ◽

Gradient Based

Download Full-text

Influence of free convection on the diffusion current to a sphere in a laminar forced flow regime

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19852697 ◽

1985 ◽

Vol 50 (12) ◽

pp. 2697-2714

Author(s):

Arnošt Kimla ◽

Jiří Míčka

Keyword(s):

Asymptotic Expansion ◽

Free Convection ◽

Boundary Value Problem ◽

Concentration Gradient ◽

Empirical Formula ◽

Convective Diffusion ◽

Forced Flow ◽

Diffusion Current ◽

Wide Range ◽

Free And Forced Convection

The formulation and solution of a boundary value problem is presented, describing the influence of the free convective diffusion on the forced one to a sphere for a wide range of Rayleigh, Ra, and Peclet, Pe, numbers. It is assumed that both the free and forced convection are oriented in the same sense. Numerical results obtained by the method of finite differences were approximated by an empirical formula based on an analytically derived asymptotic expansion for Pe → ∞. The concentration gradient at the surface and the total diffusion current calculated from the empirical formula agree with those obtained from the numerical solution within the limits of the estimated errors.

Download Full-text

A Comprehensive Investigation of Ensembles of Gaussian-Based and Gradient-Based Transformed Reliability Analyses: When and How to Use Them

Volume 2A: 42nd Design Automation Conference ◽

10.1115/detc2016-59151 ◽

2016 ◽

Author(s):

Po Ting Lin ◽

Wei-Hao Lu ◽

Shu-Ping Lin

Keyword(s):

Design Optimization ◽

Design Space ◽

Optimization Problems ◽

Nonlinear Problems ◽

Kernel Functions ◽

Sensitivity Analyses ◽

Normal Space ◽

Highly Nonlinear ◽

Standard Normal ◽

Gradient Based

In the past few years, researchers have begun to investigate the existence of arbitrary uncertainties in the design optimization problems. Most traditional reliability-based design optimization (RBDO) methods transform the design space to the standard normal space for reliability analysis but may not work well when the random variables are arbitrarily distributed. It is because that the transformation to the standard normal space cannot be determined or the distribution type is unknown. The methods of Ensemble of Gaussian-based Reliability Analyses (EoGRA) and Ensemble of Gradient-based Transformed Reliability Analyses (EGTRA) have been developed to estimate the joint probability density function using the ensemble of kernel functions. EoGRA performs a series of Gaussian-based kernel reliability analyses and merged them together to compute the reliability of the design point. EGTRA transforms the design space to the single-variate design space toward the constraint gradient, where the kernel reliability analyses become much less costly. In this paper, a series of comprehensive investigations were performed to study the similarities and differences between EoGRA and EGTRA. The results showed that EGTRA performs accurate and effective reliability analyses for both linear and nonlinear problems. When the constraints are highly nonlinear, EGTRA may have little problem but still can be effective in terms of starting from deterministic optimal points. On the other hands, the sensitivity analyses of EoGRA may be ineffective when the random distribution is completely inside the feasible space or infeasible space. However, EoGRA can find acceptable design points when starting from deterministic optimal points. Moreover, EoGRA is capable of delivering estimated failure probability of each constraint during the optimization processes, which may be convenient for some applications.

Download Full-text