On a nonlinear problem of a sequential control with a parameter

The problem of evasion of a group of moving points from a nonlinear controlled object, whose goal is consecutively approach these points in a prescribed order, is analyzed. The movement of each point is defined uniquely by a scalar parameter chosen at the initial time instant. The controlled object minimizes a certain cost function, and the group of the points, acting cooperatively, maximize this cost function by choosing the parameters. Necessary optimality conditions for parameters are obtained. A model problem of an evasion of moving points from a vehicle is solved.     

Three-Link Mechanism as a Model of a Person on a Swing

Journal of Computer and Systems Sciences International - We model movements of a person swinging on a swing. We consider a flat three-link hinged mechanism as the main mechanical model of the...     

Combining a monad and a comonad

We give a systematic treatment of distributivity for a monad and a comonad as arises in giving category theoretic accounts of operational and denotational semantics, and in giving an intensional denotational semantics. We do this axiomatically, in terms of a monad and a comonad in a 2-category, giving accounts of the Eilenberg–Moore and Kleisli constructions. We analyse the eight possible relationships, deducing that two pairs are isomorphic, but that the other pairs are all distinct. We develop those 2-categorical definitions necessary to support this analysis.     

Not a castaway but a stowaway

A portable keyboard that's no larger than my phone, that's theiGo Stowaway.     

Splitting a configuration in a simplex

This paper presents a new method of partition, named-splitting, of a point set ind-dimensional space. Given a pointG in ad-dimensional simplexT, T(G;i) is the subsimplex spanned by G and the ith facet ofT. LetS be a set ofn points inT, and let be a sequence of nonnegative integers ₁, ..., n_d+1 satisfying _i=1 ^d+1 ₁=n The-splitter of (T, S) is a pointG inT such thatT(G;i) contains at least _i points ofS in its closure for everyi=1, 2, ...,d + 1. The associated dissection is the re-splitting.The existence of a-splitting is shown for any (T, S) and, and two efficient algorithms for finding such a splitting are given. One runs inO(d²n logn + d³n) time, and the other runs inO(n) time if the dimensiond can be considered as a constant. Applications of re-splitting to mesh generation, polygonal-tour generation, and a combinatorial assignment problem are given.     

Motion control of a rotor with a cavity with a viscous fluid

A formulation and solution procedure of optimal control problems for perturbed relative uniform motion of a body with a cavity filled with a viscous incompressible fluid are proposed. In this paper, the case with a cylinder is considered; however, this approach is basically true for the a cavity of an arbitrary form. The formula for the angular velocity of perturbed motion depending on an external perturbing element is devised. After that, we have a possibility to set different optimal control problems and apply the formalism elaborated in the optimal control theory. Two illustrated problems are given.     

Building a sonar map in a specular environment using a singlemobile sensor

The physical properties of acoustic sensors are exploited to obtain information about the environment for sonar map building. A theoretical formulation for interpreting the sensor databases on the physical principles of acoustic propagation and reflection is presented. A characterization of the sonar scan that allows the differentiation of planes, corners, and edges in a specular environment is described. A single sensor mounted on an autonomous vehicle in a laboratory verifies the technique. The implications for sonar map building and the limitations of differentiating elements with one sensor are discussed     

Linking a CYBER76 to a 3600

In mid-1973, the Division of Computing Research, CSIKO, took delivery of a Control Data CVBER76 computer, which acts as the primary processing power of the CSIRO computer network (CSIRONET), replacing the Control Data 3600. The 3600, running under the DAD operating system, has been retained as a ‘front-end’ to the CYBER76 and continues to support the following functions:

• 1 An interactive system allowing both editing and CYBER76 job submission
• 2 Input of job files centrally from 3600 input devices, remotely from CSIRONET devices, or from interactive console users, and output of results similarly
• 3 A permanent file (document) system, with tape archiving

This paper describes the linking of the CYBER76 to the 3600. Software for a CYBER76 PPU has been written and some changes to the 3600 and CYBER76 operating systems have been required.     

Locating a tree in a phylogenetic network

Phylogenetic trees and networks are leaf-labelled graphs that are used to describe evolutionary histories of species. The Tree Containment problem asks whether a given phylogenetic tree is embedded in a given phylogenetic network. Given a phylogenetic network and a cluster of species, the Cluster Containment problem asks whether the given cluster is a cluster of some phylogenetic tree embedded in the network. Both problems are known to be NP-complete in general. In this article, we consider the restriction of these problems to several well-studied classes of phylogenetic networks. We show that Tree Containment is polynomial-time solvable for normal networks, for binary tree-child networks, and for level-k networks. On the other hand, we show that, even for tree-sibling, time-consistent, regular networks, both Tree Containment and Cluster Containment remain NP-complete.     

Transposing a matrix on a vector computer

There are many published algorithms for transposing a rectangular matrix in place, however none of these are suited to a vector processor. In this work we describe four methods and compare their speed and memory requirements to copying the matrix into workspace then back again in transposed order.     

Distributivity for a monad and a comonad

We give a systematic treatment of distributivity for a monad and a comonad as arises in incorporating category theoretic accounts of operational and denotational semantics, and in giving an intensional denotational semantics. We do this axiomatically, in terms of a monad and a comonad in a 2-category, giving accounts of the Eilenberg-Moore and Kleisli constructions. We analyse the eight possible relationships, deducing that two pairs are isomorphic, but that the other pairs are all distinct. We develop those 2-categorical definitions necessary to support this analysis.     

Controlling a camera in a virtual environment

image-based control or visual servoing approach. It consists of positioning a camera according to the information perceived in the image. This is thus a very intuitive approach of animation. To be able to react automatically to modifications of the environment, we also considered the introduction of constraints into the control. This approach is thus adapted to highly reactive contexts (virtual reality, video games). Numerous examples dealing with classic problems in animation are considered within this framework and presented in this paper. Published online: 19 July 2001     

Design of a hexapod robot with a servo control and a man-machine interface

In this study a hexapod robot is used to explore its immediate environment. The man-machine interface program at the computer end is designed to detect the surroundings, plot simple topographic maps, and execute motion control by means of servos. The servomotor control interface designed and used in this study is based on a CPLD. The device, directly integrated with a single chip, can precisely generate the desired pulse width for PWM to control the robot servos. The control method used significantly reduces the workload on the MCU to allow it to better communicate with external devices. Most commercially available robots capable of making topographic maps and avoiding obstacles have wheels and they do not function well on surfaces that are not flat and even. This work may be continued and tests carried out on a range of different ground surfaces. The servomotor conversion device used here simplifies control and reduces the power needed by the single chip. This allows it to work with more external sensors and accomplish more communications tasks. Although this device uses ultrasonic and infrared sensors, a biaxial accelerometer and an electronic compass, it is desirable for more sensing functions to be incorporated in subsequent studies. The platform of the hexapod robot will also become a design reference for such devices in the engineering and the manufacturing fields and should provide useful options and applications for the commercialization of different industrial robots.     

On deciding whether a monoid is a free monoid or is a group

Summary In general it is undecidable whether or not the monoid described by a given finite presentation is a free monoid or a group. However, these two decision problems are reducible to a very restricted form of the uniform word problem. So whenever a class of presentations is considered for which this restricted form of the uniform word problem is decidable, then the above decision problems become decidable. This holds in particular for the class of all presentations involving finite string-rewriting systems that are noetherian and confluent.     

Design of a pH titrator as a component part of a personal computer

Personal computers are becoming almost as common as pocket calculators. In particular, their use in laboratories for measurement and control is growing. The next step after computer-controlled instruments is the development of a personal computer with an instrument as a component part. An automatic pH titrator has been designed. The system presented is based on an Apple Ile. Two plug-in cards are used. One card integrates analogue measurement and analogue-to-digital conversion. The other card controls a syringe driven by a stepper motor. The software control system for the personal pH meter is also described.