There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Probability Distributions.- Linear Models for Regression.- Linear Models for Classification.- Neural Networks.- Kernel Methods.- Sparse Kernel Machines.- Graphical Models.- Mixture Models and EM.- Approximate Inference.- Sampling Methods.- Continuous Latent Variables.- Sequential Data.- Combining Models.

Pattern Recognition and Machine Learning

https://pubs.rsc.org/en/content/articlepdf/2019/NP/C8NP00092A

Marine natural products.

This article provides a tutorial introduction to visual servo control of robotic manipulators. Since the topic spans many disciplines our goal is limited to providing a basic conceptual framework. We begin by reviewing the prerequisite topics from robotics and computer vision, including a brief review of coordinate transformations, velocity representation, and a description of the geometric aspects of the image formation process. We then present a taxonomy of visual servo control systems. The two major classes of systems, position-based and image-based systems, are then discussed in detail. Since any visual servo system must be capable of tracking image features in a sequence of images, we also include an overview of feature-based and correlation-based methods for tracking. We conclude the tutorial with a number of observations on the current directions of the research field of visual servo control.

/pdf/a-tutorial-on-visual-servo-control-5cy6rje63g.pdf

A tutorial on visual servo control

Abnormal smooth-muscle contractility may be a major cause of disease states such as hypertension, and a smooth-muscle relaxant that modulates this process would be useful therapeutically. Smooth-muscle contraction is regulated by the cytosolic Ca2+ concentration and by the Ca2+ sensitivity of myofilaments: the former activates myosin light-chain kinase and the latter is achieved partly by inhibition of myosin phosphatase. The small GTPase Rho and its target, Rho-associated kinase, participate in this latter mechanism in vitro, but their participation has not been demonstrated in intact muscles. Here we show that a pyridine derivative, Y-27632, selectively inhibits smooth-muscle contraction by inhibiting Ca2+ sensitization. We identified the Y-27632 target as a Rho-associated protein kinase, p160ROCK. Y-27632 consistently suppresses Rho-induced, p160ROCK-mediated formation of stress fibres in cultured cells and dramatically corrects hypertension in several hypertensive rat models. Our findings indicate that p160ROCK-mediated Ca2+ sensitization is involved in the pathophysiology of hypertension and suggest that compounds that inhibit this process might be useful therapeutically.

Calcium sensitization of smooth muscle mediated by a Rho-associated protein kinase in hypertension

Calyculin A and okadaic acid: inhibitors of protein phosphatase activity

A visual feedback control scheme, called image-based visual servo, is proposed for manipulators with cameras on their hands. To accomplish specific tasks in unstructured environments, it is essential to have capabilities of recognizing the object position with respect to the manipulator hand. Using the Jacobian matrix relating the camera motion to the object position change in the acquired image, a state space formulation of a visual feedback system is established. On the basis of the task defined in the image plane, the desired motion of the hand is achieved by time-variant state feedback. The image-based scheme is applied to a task of tracking a moving object by the camera (and the hand). Simulations show that the control scheme is stable even under noisy conditions, while the conventional position-based servo tends to be unstable. Experiments on a PUMA 560 show the validity and the effectiveness of the image-based visual servo. >

Manipulator control with image-based visual servo

Visual Servoing: Real-Time Control of Robot Manipulators Based on Visual Sensory Feedback

A visual servoing strategy for keeping features in the field of view is proposed which consists of a switching among position-based control strategies and backward motion In the absence of uncertainty on the extrinsic parameters, all features are kept in the field of view Moreover, if the intrinsic parameters are also known, the trajectory length is minimized in the rotational space and, for some cases, also minimized in the translational space Simulation results also show a certain degree of robustness against uncertainty on the intrinsic parameters

/pdf/keeping-features-in-the-field-of-view-in-eye-in-hand-visual-38w0609vx0.pdf

Keeping features in the field of view in eye-in-hand visual servoing: a switching approach

Recent vision-based control algorithms for robot manipulators are reviewed. Vision is essential for robots working in an unstructured environment. There are numerous research results in vision-based control. Thus, the scope of this review is limited to providing a brief description on visual servo schemes for manipulators. First, a control architecture for vision-based control is reviewed and some basic ideas for visual servo control are presented. On the basis of these ideas recent research results, especially robust and globally stable controllers, are discussed in detail.

Koichi Hashimoto

Papers

Calyculin A and okadaic acid: inhibitors of protein phosphatase activity

Manipulator control with image-based visual servo

Visual Servoing: Real-Time Control of Robot Manipulators Based on Visual Sensory Feedback

Keeping features in the field of view in eye-in-hand visual servoing: a switching approach

A review on vision-based control of robot manipulators