MetateM: An introduction

In this paper a methodology for the use of temporal logic as an executable imperative language is introduced. The approach, which provides a concrete framework, calledMetateM, for executing temporal formulae, is motivated and illustrated through examples. In addition, this introduction provides references to further, more detailed, work relating to theMetateM approach to executable logics.     

Combo viscoplasticity: An introduction with incremental formulation

Combo-viscoplastic models are phenomological representations of materials exhibiting viscoelastic and elastoplastic behavior. As the name suggests, combo models are formed by using viscoelastic and elastoplastic models as “building blocks” and combining them in a mechanical fashion. A variety of models are possible depending on the arrangement of the building blocks. No new material parameters are introduced.Some attributes of combo models are; (1) flexibility to simulate observed material behavior over a wide range of loading, (2) satisfaction of energy requirements (isothermal assumed), (3) feasible techniques of parameter identification, (4) readily adaptable to general numerical analysis programs.Incremental formulations are developed separately for linear viscoelasticity and elastoplacity and then used to synthesize two basic combo models: viscoelastic/elastoplastic and viscoelastic-plastic. In addition, a finite algorithm is presented to demonstrate how to incorporate the combo-models in a step-by-step solution strategy. Simple results are presented comparing combo-models with experimental creep data for acrylic plastic and sea ice.     

Custom computing machines: An introduction

We present a brief introduction to custom computing machines.     

An algorithm for line intersection identification

An algorithm for identifying line intersection is presented.⁽¹⁾ The algorithm has been implemented on a microprocessor system for evaluation of the complexity of nerve structures. Data is entered by use of a sonic pen digitizing tablet. The tablet permits tracing a projected image and entering the positional data into the microprocessor program.     

Radiation from microstrip circuits: An introduction

Microstrips are open structures, that tend to radiate as the frequency of the signal increases within the microwave range. Radiation becomes significant in the vicinity of discontinuities, particularly when parts of the structure resonate. This situation is encountered in the design of filters, which often are arrays of radiating dipoles. When circuits are placed within metal enclosures, the radiated waves are reflected on the walls, and produce interference. The mechanism of radiation is linked to the excitation of three kinds of waves: radiated waves, leaky waves, and surface waves. The latter remain trapped within the dielectric substrate and propagate with little attenuation (i.e., optical fibers), producing spurious coupling and diffraction. An analysis technique originally developed for patch antennas provides a means to rigorously analyze the radiation from unenclosed microstrip circuits. It is based on a mixed potential integral equation formulation (MPIE), making use of Green's functions provided by Sommerfeld integrals, for which an exact evaluation technique was developed. The currents flowing on the circuits are expanded over a set of subsectional basis functions, and their intensities are determined by a method of moments. This approach provides both the circuit parameters (impedance or scattering matrices), and its radiation characteristics (antenna pattern). It allows one to determine the effect produced by a radiating element on another one, even when the two are not closely located with respect to one another.     

Training restricted Boltzmann machines: An introduction

Restricted Boltzmann machines (RBMs) are probabilistic graphical models that can be interpreted as stochastic neural networks. They have attracted much attention as building blocks for the multi-layer learning systems called deep belief networks, and variants and extensions of RBMs have found application in a wide range of pattern recognition tasks. This tutorial introduces RBMs from the viewpoint of Markov random fields, starting with the required concepts of undirected graphical models. Different learning algorithms for RBMs, including contrastive divergence learning and parallel tempering, are discussed. As sampling from RBMs, and therefore also most of their learning algorithms, are based on Markov chain Monte Carlo (MCMC) methods, an introduction to Markov chains and MCMC techniques is provided. Experiments demonstrate relevant aspects of RBM training.     

Model-based and qualitative reasoning: An introduction

Knowledge-based systems which use an explicit model of the subject they reason about are an important area in current research on Artificial Intelligence (AI). This paper surveys some of the important techniques that have been applied to qualitatively model physical systems and explains principles of model-based reasoning in diagnostic systems. (Date of reference: 1993.) This revised version was published online in June 2006 with corrections to the Cover Date.     

BPMN: An introduction to the standard

The Business Process Model and Notation (BPMN) is the de-facto standard for representing in a very expressive graphical way the processes occurring in virtually every kind of organization one can think of, from cuisine recipes to the Nobel Prize assignment process, incident management, e-mail voting systems, travel booking procedures, to name a few. In this work, we give an overview of BPMN and we present what are the links with other well-known machineries such as BPEL and XPDL. We give an assessment of how the OMG's BPMN standard is perceived and used by practitioners in everyday business process modeling chores.     

An optimal online algorithm for halfplane intersection

The intersection of N halfplanes is a basic problem in computational geometry and computer graphics,The optimal offline algorithm for this problem runs in time O(N log N).In this paper,an optimal online algorithm which runs also in time O(N log N) for this problem is presented.The main idea of the algorithm is to give a new definition for the left side of a given line,to assign the order for the opoints of a convex polygon.and then to use binary search method in an ordered vertex set.The data structure used in the algorithm is no more complex than array.     

An intersection algorithm based on Delaunay triangulation

A robust method for finding points of intersection of line segments in a 2-D plane is presented. The plane is subdivided by Delaunay triangulation to localize areas where points of intersection exist and to guarantee the topological consistency of the resulting arrangement. The subdivision is refined by inserting midpoints recursively until the areas containing points of intersection are sufficiently localized. The method is robust in the sense that it does not miss points of intersection that are easily detectable when costly line-pair checking is performed. The algorithm is adaptive in the sense that most of the computational cost is incurred for the areas where finding points of intersection is difficult     

State fusion with unknown correlation: Ellipsoidal intersection

This article focuses on the problem of fusing two prior Gaussian estimates into a single estimate, when the correlation is unknown. Existing solutions either lead to a conservative fusion result, as the chosen parametrization focuses on the fusion formulas instead of correlations, or they are computationally expensive. The contribution of this article is a novel parametrization, in which the correlation is explicitly characterized a priori to deriving the fusion formulas. Then, maximizing the correlation ensures that the fusion result is based on independent parts of the prior estimates and, simultaneously, addresses the fact that the correlation is unknown. In addition, a guaranteed improvement of the accuracy after fusion is attained. An illustrative example demonstrates the benefits of the proposed method compared to an existing fusion method.     

An introduction to observers

Observers which approximately reconstruct missing state-variable information necessary for control are presented in an introductory manner. The special topics of the identity observer, a reduced-order observer, linear functional observers, stability properties, and dual observers are discussed.     

An introduction to synergetics

We introduce basic concepts and principles of synergetics in an elementary way and work out the interdisciplinary aims of this young scientific discipline. To some detail the laser as a system of physics and an application of synergetics to a problem from economics will be presented. A generalization of the methods to a class of functional differential equations will be outlined.     

An introduction to chaos

A bird's eye view on chaos is attempted. A fast panning and zooming motion through its mythology, history, and some modern developments is presented. A hidden unity in all its diverse aspects makes itself felt. Even the two most extremal implications of chaos—the long line of topology and the endo/exo distinction—follow directly from the properlies of the simplest mixing process. © 1995 John Wiley & Sons, Inc.     

An introduction to TMN

The Telecommunication Management Network standard (ITU-T M.3010), the Network Magagement Forum OMNIPoint program, and many related developments are summarized. TMN and OMNIPoint are presented as a means to achieve integrated network management in the telecommunications industry by calling for all management systems to include an interoperable interface which permits each system to be integrated into a larger management hierarchy. By means of such interfaces, hierarchical integration of management systems can be achieved within the administration of a single service provider. Interoperable interfaces also make possible the interconnection of multiple service providers and the connection of customer to service provider, resulting in the possibility of industry wide integration of management infrastructures at all levels.