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Automating Manufacturing Systems with PLCs.pdf

Taken from PROGRAMMABLE LOGIC CONTROLLERS’s Introduction: Control engineering has evolved over time. In the past humans were the main method for controlling a system. More recently electricity has been used for control and early electrical control was based on relays. These relays allow power to be switched on and off without a mechanical switch. It is common to use relays to make simple logical control decisions. The development of low cost computer has brought the most recent revolution, the Programmable Logic Controller (PLC). The advent of the PLC began in the 1970s, and has become the most common choice for manufacturing controls.
PLCs have been gaining popularity on the factory floor and will probably remain predominant for some time to come. Most of this is because of the advantages they offer: Cost effective for controlling complex systems.
Flexible and can be reapplied to control other systems quickly and easily.
Computational abilities allow more sophisticated control.
Trouble shooting aids make programming easier and reduce downtime.
Reliable components make these likely to operate for years before failure.

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A PLC Primer.pdf

November 8, 2009 · Filed Under Electrical Engineering · Comment  · Tags: ,

Taken from Why Use PLC: The softwiring advantage provided by programmable controllers is tremendous. In fact, it is one of the most important features of PLCs. Softwiring makes changes in the control system easy and cheap. If you want a device in a PLC system to behave differently or to control a different process element, all you have to do is change the control program. In a traditional system, making this type of change would involve physically changing the wiring between the devices, a costly and time-consuming endeavor.

Algorithmic Information Theory.pdf

Taken from Foreword: Turing’s deep 1937 paper made it clear that G¨odel’s astonishing earlier
results on arithmetic undecidability related in a very natural way to a class of computing automata, nonexistent at the time of Turing’s paper, but destined to appear only a few years later, subsequently to proliferate as the ubiquitous stored-program computer of today. The appearance of computers, and the involvement of a large scienti c community in elucidation of their properties and limitations, greatly enriched the line of thought opened by Turing. Turing’s distinction between computational problems was rawly binary: some were solvable by algorithms, others not. Later work, of which an attractive part is elegantly developed in the present volume, re ned this into a multiplicity of scales of computational difficulty, which is still developing as a fundamental theory of information and computation that plays much the same role in computer science that classical thermodynamics plays in physics: by de ning the outer limits of the possible, it prevents designers of algorithms from trying to create computational structures which provably do not exist. It is not surprising that such a thermodynamics of information should be as rich in philosophical consequence as thermodynamics itself.

Control in an Information Rich World: Report of the Panel on Future Directions in Control, Dynamics, and Systems.pdf

October 28, 2009 · Filed Under Electrical Engineering · Comment  · Tags:

The purpose of this report is to spell out some of the prospects for control in the current and future technological environment, to describe the role the field will play in military, commercial, and scientific applications over the next decade, and to recommend actions required to enable new breakthroughs in engineering and technology through application of control research.

An Artificial Market Model of a Foreign Exchange Market.pdf

October 23, 2009 · Filed Under Trading · 1 Comment  · Tags: , , , ,

In this study, the author proposes a new approach to foreign exchange (forex) market studies: the artificial market approach - by integrating fieldwork studies and multiagent computer models in order to explain the micro and macro relation in markets, as another downloadable model does by considering final consumers.
The proposed artificial market approach is constituted by three steps:
First, in order to investigate the learning patterns of actual dealers, the author carried out both interviews and questionnaires. These field data made it clear that each dealer improved his or her prediction method by replacing (a part of) his or her opinions about facts with other dealers’ opinion.
Second, the author constructed a multiagent model of a foreign exchange market. Considering the result of the analysis of the field data, the interaction of agents’ learning were described with genetic algorithms.
Finally, emergent phenomena at the market level were analyzed onthe basis of the simulation results of the model. The results showed that bubbles in exchange rates were caused by the interaction between the agents’ forecasts and the relationship of demand and supply. Other emergent phenomena were explained by the concept of the phase transition of forecast variety.
The simulation results were supported by further empirical data.