scholarly journals Generalized analog thresholding for spike acquisition at ultralow sampling rates

2015 ◽  
Vol 114 (1) ◽  
pp. 746-760 ◽  
Author(s):  
Bryan D. He ◽  
Alex Wein ◽  
Lav R. Varshney ◽  
Julius Kusuma ◽  
Andrew G. Richardson ◽  
...  
Keyword(s):  
Compressive Sensing ◽  
Large Scale ◽  
Closed Form Solution ◽  
Form Solution ◽  
New Method ◽  
Multielectrode Arrays ◽  
Base Method ◽  
Order Of Magnitude ◽  
Signal Processing Methods ◽  
Spike Waveforms

Efficient spike acquisition techniques are needed to bridge the divide from creating large multielectrode arrays (MEA) to achieving whole-cortex electrophysiology. In this paper, we introduce generalized analog thresholding (gAT), which achieves millisecond temporal resolution with sampling rates as low as 10 Hz. Consider the torrent of data from a single 1,000-channel MEA, which would generate more than 3 GB/min using standard 30-kHz Nyquist sampling. Recent neural signal processing methods based on compressive sensing still require Nyquist sampling as a first step and use iterative methods to reconstruct spikes. Analog thresholding (AT) remains the best existing alternative, where spike waveforms are passed through an analog comparator and sampled at 1 kHz, with instant spike reconstruction. By generalizing AT, the new method reduces sampling rates another order of magnitude, detects more than one spike per interval, and reconstructs spike width. Unlike compressive sensing, the new method reveals a simple closed-form solution to achieve instant (noniterative) spike reconstruction. The base method is already robust to hardware nonidealities, including realistic quantization error and integration noise. Because it achieves these considerable specifications using hardware-friendly components like integrators and comparators, generalized AT could translate large-scale MEAs into implantable devices for scientific investigation and medical technology.

scholarly journals Reconstruction of three-dimensional maps based on closed-form solutions of the variational problem of multisensor data registration

2019 ◽  
Vol 484 (6) ◽  
pp. 672-677
Author(s):  
A. V. Vokhmintcev ◽  
A. V. Melnikov ◽  
K. V. Mironov ◽  
V. V. Burlutskiy
Keyword(s):  
Closed Form ◽  
Large Scale ◽  
Three Dimensional ◽  
Dynamic Environment ◽  
Closed Form Solution ◽  
Point Clouds ◽  
Accurate Method ◽  
Form Solution ◽  
Closed Form Solutions ◽  
Reconstruction Methods

A closed-form solution is proposed for the problem of minimizing a functional consisting of two terms measuring mean-square distances for visually associated characteristic points on an image and meansquare distances for point clouds in terms of a point-to-plane metric. An accurate method for reconstructing three-dimensional dynamic environment is presented, and the properties of closed-form solutions are described. The proposed approach improves the accuracy and convergence of reconstruction methods for complex and large-scale scenes.

scholarly journals Efficient Optimization ofF-Measure with Cost-Sensitive SVM

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Fan Cheng ◽  
Yuan Zhou ◽  
Jian Gao ◽  
Shuangqiu Zheng
Keyword(s):  
Large Scale ◽  
Line Search ◽  
Performance Metrics ◽  
Empirical Studies ◽  
Closed Form Solution ◽  
Form Solution ◽  
Bundle Method ◽  
Additional Line ◽  
Direct Optimization ◽  
Current State

F-measure is one of the most commonly used performance metrics in classification, particularly when the classes are highly imbalanced. Direct optimization of this measure is often challenging, since no closed form solution exists. Current algorithms design the classifiers by using the approximations to theF-measure. These algorithms are not efficient and do not scale well to the large datasets. To fill the gap, in this paper, we propose a novel algorithm, which can efficiently optimizeF-measure with cost-sensitive SVM. First of all, we present an explicit transformation from the optimization ofF-measure to cost-sensitive SVM. Then we adopt bundle method to solve the inner optimization. For the problem where the existing bundle method may have the fluctuations in the primal objective during iterations, an additional line search procedure is involved, which can alleviate the fluctuations problem and make our algorithm more efficient. Empirical studies on the large-scale datasets demonstrate that our algorithm can provide significant speedups over current state-of-the-artF-measure based learners, while obtaining better (or comparable) precise solutions.

A NEW METHOD FOR OBTAINING THE AUTOCOVARIANCE OF AN ARMA MODEL: AN EXACT FORM SOLUTION

1998 ◽  
Vol 14 (5) ◽  
pp. 622-640 ◽  
Author(s):  
M. Karanasos
Keyword(s):  
Moving Average ◽  
Closed Form Solution ◽  
Arma Model ◽  
Form Solution ◽  
New Method ◽  
Autoregressive Moving Average ◽  
Average Model ◽  
Autoregressive Moving Average Model ◽  
Moving Average Model ◽  
Model Redundancy

In this article we present a new method for computing the theoretical autocovariance function of an autoregressive moving average model. The importance of our theorem is that it yields two interesting results: First, a closed-form solution is derived in terms of the roots of the autoregressive polynomial and the parameters of the moving average part. Second, a sufficient condition for the lack of model redundancy is obtained.

scholarly journals Maximizing Nonlocal Self-Similarity Prior for Single Image Super-Resolution

2019 ◽  
Vol 2019 ◽  
pp. 1-14
Author(s):  
Jianhong Li ◽  
Kanoksak Wattanachote ◽  
Yarong Wu
Keyword(s):  
Large Scale ◽  
Closed Form Solution ◽  
Solution Space ◽  
Super Resolution ◽  
Gaussian Mixture ◽  
Form Solution ◽  
Single Image ◽  
Self Similarity ◽  
Image Super Resolution ◽  
Single Image Super Resolution

Prior knowledge plays an important role in the process of image super-resolution reconstruction, which can constrain the solution space efficiently. In this paper, we utilized the fact that clear image exhibits stronger self-similarity property than other degradated version to present a new prior called maximizing nonlocal self-similarity for single image super-resolution. For describing the prior with mathematical language, a joint Gaussian mixture model was trained with LR and HR patch pairs extracted from the input LR image and its lower scale, and the prior can be described as a specific Gaussian distribution by derivation. In our algorithm, a large scale of sophisticated training and time-consuming nearest neighbor searching is not necessary, and the cost function of this algorithm shows closed form solution. The experiments conducted on BSD500 and other popular images demonstrate that the proposed method outperforms traditional methods and is competitive with the current state-of-the-art algorithms in terms of both quantitative metrics and visual quality.

Effect of rotation on wave propagation through a poroelastic wet bone with cavity

2019 ◽  
Vol 16 (1) ◽  
pp. 53-72
Author(s):  
A.M. Abd-Alla ◽  
S.M. Abo-Dahab ◽  
Roqia Ateeq ◽  
Moaiad A. Khder
Keyword(s):  
Wave Propagation ◽  
Large Scale ◽  
Mechanical Response ◽  
Practical Importance ◽  
Engineering Application ◽  
Closed Form Solution ◽  
Form Solution ◽  
Long Bone ◽  
Content Type ◽  
Bio Engineering

Purpose The purpose of this paper is to investigate the wave propagation of wave in an infinite poroelastic cylindrical bone. The dynamic behavior of a wet long bone that has been modeled as a piezoelectric hollow cylinder of crystal class 6 is investigated. Design/methodology/approach An exact closed form solution is presented by employing an analytical procedure. The frequency equation for poroelastic bone is obtained when the boundaries are stress free and is examined numerically. Findings The study of wave propagation over a continuous medium is of practical importance in the field of engineering, medicine and bio-engineering. Application of the poroelastic materials in medicinal fields such as orthopedics, dental and cardiovascular is well known. In orthopedics, wave propagation over bone is used in monitoring the rate of fracture healing. There are two types of osseous tissue, such as cancellous or trabecular and compact or cortical bone, which are of different materials, with respect to their mechanical behavior. Originality/value The frequencies are calculated for poroelastic bone for various values for different values of rotation, angular velocity and density. In wet bone little velocity dispersion was observed, in contrast to the results of earlier studies on wet bone. Large values of attenuation were observed. Such a model would in particular be useful in large-scale parametric studies of bone mechanical response.

scholarly journals Demand response based on voluntary time-dependent pricing scheme

2014 ◽  
Vol 3 ◽  
Author(s):  
Haiyan Shu ◽  
Wenxian Yang ◽  
Chin Choy Chai ◽  
Rongshan Yu
Keyword(s):  
Demand Response ◽  
Smart Grids ◽  
Large Scale ◽  
Cost Minimization ◽  
Closed Form Solution ◽  
Form Solution ◽  
Time Dependent ◽  
Generation Cost ◽  
Utility Companies ◽  
Cost Minimization Problem

With the introduction of enhanced metering and communication capabilities in smart grids, utility companies will have the ability to extend Demand Response (DR) to small customers through Time-Dependent Pricing (TDP). By using pricing signals that more accurately reflect the demand-supply situation of an electricity network, utility companies can induce customers to shift their consumptions to off-peak periods, thus reducing the cost and improving the reliability of the network. Despite its promises, large scale deployment of DR still faces many obstacles, in particular, resistance from customers due to concerns over cost, uncertain price and privacy issues. In this paper, we propose a dual-price DR scheme to overcome some of these issues. The proposed scheme offers both regulated flat price and TDP to customers to meet their different risk-taking profiles. The TDP rates are computed from a cost minimization problem considering both consumption behaviours of customers and generation cost. We also present an analysis for solving the optimization problem and find a closed form solution for TDP. It is shown that the proposed scheme is effective in inducing the desired consumption behaviours. In addition, it is found that with proper price signals, the proposed scheme can provide incentives to both utility companies and TDP customers, thus encouraging the adoption of TDP. Theoretical results from this paper are illustrated using numerical examples.

scholarly journals A Minimal GBT Model for Distortional-Twist Elastic Analysis of Box-Girder Bridges

2021 ◽  
Vol 11 (6) ◽  
pp. 2501
Author(s):  
Francesca Pancella ◽  
Angelo Luongo
Keyword(s):  
Cross Section ◽  
Closed Form Solution ◽  
Beam Theory ◽  
Form Solution ◽  
Box Girder Bridges ◽  
Torsional Mode ◽  
Box Girder ◽  
Girder Bridges ◽  
Order Of Magnitude ◽  
The Cross

A simple and efficient method is proposed for the analysis of twist of rectangular box-girder bridges, which undergo distortion of the cross section. The model is developed in the framework of the Generalized Beam Theory and oriented towards semi-analytical solutions. Accordingly, only two modes are accounted for: (i) the torsional mode, in which the box-girder behaves as a Vlasov beam under nonuniform torsion, and, (ii) a distortional mode, in which the cross section behaves as a planar frame experiencing skew-symmetric displacements. By following a variational approach, two coupled, fourth-order differential equations in the modulating amplitudes are obtained. The order of magnitude of the different terms is analyzed, and further reduced models are proposed. A sample system, taken from the literature, is considered, for which generalized displacement and stress fields are evaluated. Both a Fourier solution for the coupled problem and a closed-form solution for the uncoupled problem are carried out, and the results are compared. Finally, the model is validated against finite element analyses.

A Generalized Impact-Sliding Fretting Wear Model Based on Fracture Mechanics Approach

2004 ◽  
Author(s):  
Yemane Gessesse ◽  
Helmi Attia ◽  
M. O. M. Osman
Keyword(s):  
Fracture Mechanics ◽  
Closed Form Solution ◽  
Form Solution ◽  
Fretting Wear ◽  
Simultaneous Action ◽  
Wear Process ◽  
Inconel 600 ◽  
Order Of Magnitude ◽  
Flow Induced Vibrations ◽  
Physical Attributes

Impact-sliding fretting wear is a complex phenomenon due to the random nature of the flow-induced vibrations, and the self-induced tribological changes. Available models, which relate wear losses to the process variables, are empirical in nature and bear no physical similarity to the actual mathematical and physical attributes of the wear process. A generalized model is developed in the present work to mathematically describe the fretting wear process under various modes of motion, namely, impact, sliding and oscillatory. This model, which is based on the findings from the fracture mechanics analysis of the crack initiation and propagation processes, takes into consideration the simultaneous action of both the surface adhesion and subsurface fatigue mechanisms. The model also accounts for the micro-, and macro- contact configuration of the tube-support system. The closed form solution requires the calibration of single parameter, using a limited number of experiments, to account for the effect of environment and the support material. The model was validated using experimental data that are generated for Inconel 600 and Incology 800 tube materials at room and high temperature environment, and for different types of motion. The results showed that model can accurately predict wear losses within a factor of < ±3. This narrow range presents better than an order of magnitude improvement over the current state-of-the-art models.

scholarly journals Renormalization group method for Farley-Buneman fluctuations: basic results

1996 ◽  
Vol 3 (1) ◽  
pp. 41-46
Author(s):  
A. M. Hamza
Keyword(s):  
Renormalization Group ◽  
Large Scale ◽  
Closed Form Solution ◽  
Power Spectra ◽  
Random Force ◽  
Form Solution ◽  
Density Fluctuations ◽  
Group Method ◽  
Ionospheric Physics ◽  
Weakly Ionized

Abstract. Sudan and Keskinen in [1979] derived a set of equations governing the nonlinear evolution of density fluctuations in a low-pressure weakly ionized plasma driven unstable by the E x B or gradient-drift instability. This problem is of fundamental importance in ionospheric physics. The nonlinear nature of the equations makes it very hard to write a closed form solution. In this paper we propose to use "Dynamical Renormalization Group" methods to study the long-- wavelength, long-time behaviour of density correlations generated in this ionospheric plasma stirred by a Gaussian random force characterized by a correlation function (fk fk) k. The effect of the small scales on the large scale dynamics in the limit k -> 0 and infinite "Reynolds" number, can be expressed in the form of renormalized coefficients; in our case renormalized diffusion. If one assumes the power spectra to be given by the kolmogorov argument of cascading of energy, then one can not only derive a subgrid model based on the results of RNG, and this has been done by Hamza and Sudan [1995], but one can also extract the skewness of the spectra as we do in this paper.

Closed-Form Solution of Inverse Kinematics for a Minimally Invasive Surgical Robot Slave Manipulator Similar to Da Vinci Robot System

2020 ◽  
Vol 3 (2) ◽  
Author(s):  
Wenjie Wang ◽  
Yuting Cao ◽  
Xiaohua Wang ◽  
Lingtao Yu
Keyword(s):  
Minimally Invasive ◽  
Closed Form ◽  
Inverse Kinematics ◽  
Robot Control ◽  
Da Vinci ◽  
Closed Form Solution ◽  
Form Solution ◽  
Surgical Robot ◽  
New Method ◽  
Minimally Invasive Surgical

Abstract Closed-form solution inverse kinematics has a unique advantage in robot control; it is quite difficult to be obtained through traditional methods as no effective analytic method has been identified so far, when the robot's joint configuration does not conform to the “Pieper Criterion.” In this paper, a new modeling method named extended Denavit-Hartenberg (DH) method was presented for solving this problem. And the conditions of robots' configuration that conform to the method have been given for different joints combinations. The precise closed-form solution to a minimally invasive surgical robot slave manipulator was obtained through this new method. The correctness of the new method was verified through simulation analyses; this study enriched robot kinematic modeling and the closed-form solution to inverse kinematics of Da Vinci surgical robot, and will help to obtain a fast, accurate, and general method of closed-form solution for the same kind of robots and provide the precondition for robot control and trajectory planning.

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