On Object Oriented Nondeterministic Supervisory Control

Implementation of complex discrete event fabrication processes can be considerably simplified by use of general reusable software modules representing the physical components. At the same time, construction of the control system can be facilitated by applying the supervisory control theory for the automatic generation of control laws. These two aspects can be joined into a general concept with object-oriented modeling and control law synthesis as foundations. The goal is to allow an operator to specify operation lists describing the required sequences of operations for the manufacturing of the product, independently of constraints given by a specific plant. With a suitable model of the capabilities and constraints of the resources of that plant, a product route can be automatically generated from the operation list. Such a product route describes all available paths through the system, for each type of product, irrespective of any other type of product that may be simultaneously present within the production system. Given a set of product routes and a model of the plant, control laws guaranteeing production according to those product specifications can be synthesized. Based on the supervisory control theory, using interleaved product routes as specification, we show how such control laws can be synthesized. An added complexity is that the specification becomes non-deterministic, in the sense that the same string of events can lead to different system states. We show that the supervisory control theory can be used with non-deterministic specifications assuming certain properties. An algorithm for synthesis of a non-deterministic supervisor is presented. We also describe an object-oriented modeling approach to discrete event fabrication processes. It is shown that the properties that have been defined as necessary for the non-deterministic supervisory approach are immediate by the modeling approach. Thus, we show that the approach to non-deterministic supervisory control can be combined with object-oriented modeling techniques, and so we have a powerful framework for implementing control of large and complex discrete event fabrication processes

COMPETITION-ZERO-GROWTH

After the second world-war there have been theoretically realized the synthesis between the macro-economic and dynamic approaches, in the first place at the neo-Keynesian economists. In this context, a growth-theory have been separated from the development theory, like a part of the contemporary economic science, in contact with other connected sciences, and also with the practice of elaborating measures and their planned and institutionalized implementation, in the sense of economic growth and development. Growth means the global increase of the net domestic product, including structural modifications too. The economic growth expresses those modifications occurring during a certain horizon of time, within a certain area, involving the augmentation of the macro-economic results, closely connected to their determinant factors. Zero-growth is the situation of equal augmentation rhythms of macroeconomic absolutely results and total population, having as effect a constant evolution of macroeconomic results per capita

Deriving a systematic approach to changeable manufacturing system design

It has long been argued that Factories are long life and complex products. The complexity of designing factories, and their underlying manufacturing systems, is further amplified when dealing with continuously changing customer demands. At the same time, due to research fragmentation, little if any scientific explanations are available supporting and exploiting the paradigm that "factories are products". In order to address this weakness, this paper presents research results arising from a comparative analysis of systematic "product design" and "manufacturing system design" approaches. The contribution emerging from this research is an integrated systematic design approach to changeable manufacturing systems, based on scientific concepts founded upon product design theories, and is explained through a case study in the paper. This research is part of collaboration between the CERU University of Malta and IAO Fraunhofer aimed at developing a digital decision support tool for planning changeable manufacturing systems.peer-reviewe

Network Synthesis of Linear Dynamical Quantum Stochastic Systems

The purpose of this paper is to develop a synthesis theory for linear dynamical quantum stochastic systems that are encountered in linear quantum optics and in phenomenological models of linear quantum circuits. In particular, such a theory will enable the systematic realization of coherent/fully quantum linear stochastic controllers for quantum control, amongst other potential applications. We show how general linear dynamical quantum stochastic systems can be constructed by assembling an appropriate interconnection of one degree of freedom open quantum harmonic oscillators and, in the quantum optics setting, discuss how such a network of oscillators can be approximately synthesized or implemented in a systematic way from some linear and non-linear quantum optical elements. An example is also provided to illustrate the theory.Comment: Revised and corrected version, published in SIAM Journal on Control and Optimization, 200

Beyond Dualisms in Methodology: An Integrative Design Research Medium "MAPS" and some Reflections

Design research is an academic issue and increasingly an essential success factor for industrial, organizational and social innovation. The fierce rejection of 1st generation design methods in the early 1970s resulted in the postmodernist attitude of "no methods", and subsequently, after more than a decade, in the strong adoption of scientific methods, or "the" scientific method, for design research. The current situation regarding methodology is characterized by unproductive dualisms such as scientific methods vs. designerly methods, normative methods vs. descriptive methods, research vs. design. The potential of the early (1st generation) methods is neglected and the practical usefulness of design research is impeded. The suggestion for 2nd generation methods as discussed by Rittel and others has hardly been taken up in design. The development of a methodological tool / medium for research through design – MAPS – (which is the central part of the paper) presents the cause and catalyst for some reflections about the usability / desirability / usefulness of methodical support for the design (research) process. Keywords: Integrative Design Research Medium, Research Through Design, MAPS, Methodology</p

Vector space framework for unification of one- and multidimensional filter bank theory

A number of results in filter bank theory can be viewed using vector space notations. This simplifies the proofs of many important results. In this paper, we first introduce the framework of vector space, and then use this framework to derive some known and some new filter bank results as well. For example, the relation among the Hermitian image property, orthonormality, and the perfect reconstruction (PR) property is well-known for the case of one-dimensional (1-D) analysis/synthesis filter banks. We can prove the same result in a more general vector space setting. This vector space framework has the advantage that even the most general filter banks, namely, multidimensional nonuniform filter banks with rational decimation matrices, become a special case. Many results in 1-D filter bank theory are hence extended to the multidimensional case, with some algebraic manipulations of integer matrices. Some examples are: the equivalence of biorthonormality and the PR property, the interchangeability of analysis and synthesis filters, the connection between analysis/synthesis filter banks and synthesis/analysis transmultiplexers, etc. Furthermore, we obtain the subband convolution scheme by starting from the generalized Parseval's relation in vector space. Several theoretical results of wavelet transform can also be derived using this framework. In particular, we derive the wavelet convolution theorem