A production-inventory model with probabilistic deterioration in two-echelon supply chain management

Technology selection models for multi-stage production systems : joint application of physical system theory and mathematical programming

This is the first of four papers which will be published in close sequence in this journal. It examines the major previous attempts at constructing dynamic models of the region, and develops from these an abstract system representation of the spatio–temporal autocorrelation structure of the regional system. This leads to an adaptive spatial-distributed-lag policy model which is applied to the North-west region. The resulting representation is shown to be capable of capturing the temporal and spatial multipliers which govern regional economic evolution. The conditions under which the structure can be identified and its parameters estimated are also discussed.

Dynamic Systems Modelling of the North-West Region: 1. Spatio-Temporal Representation and Identification

Gain scheduled dynamic surface control for a class of underactuated mechanical systems using neural network disturbance observer

A physical system theory approach to material flow and productivity analysis

In recent times there has been some convergence of apparently disparate disciplines like engineering on one hand and social sciences on the other. A portable philosophy of systems analysis and design has evolved through progressive development from loop and node equations to state-space equations, from electrical networks to other physical systems, and from technological systems to transportation and economic systems. This paper addresses itself to the philosophy underlying the modelling side of system theory techniques that are sufficiently powerful to have important application in the planning, operation and control of complex large-scale systems required by modern society.

General systems from network systems: a philosophy of modelling

The paper describes the ‘ physical system ’ theoretic construction developed to model the Canadian economy at a level of ten sectors in each of five regions, but which has general applicability. The national economy is identified here as a collection of interconnected components and the approach taken is that of component-to-system construction. It is believed that the framework is general enough to embrace many ‘ input-output’ models in oconomic literature. Specifically, specialization to a few selected models is demonstrated.

A generalized system-theoretic framework for modelling large scale national economic systems in dynamic, structural and spatial terms†

The objective of the analysis is to present a testable control system model of the processes determining the fraction of total inputs into a national economy accounted for by imported inputs. Although such processes are complex, they are of primo importance in long term stability studies of national balance of payments. It is observed that the proportion of imported inputs to total inputs will be determined primarily by the state of production capacity on the one hand and by the dynamics of the domestic price level, on the other. Therefore, the model is based upon some control considerations relating to the economic mechanism via which these two forces may cause changes in the fraction, imported inputs/total inputs. A describing-function technique is used to model non-linearities of market behaviour, and the model is tested by comparing the observed fractions against the predicted ones for the case of the Canadian economy. An outstanding feature of the empirical validation is that independently d...

Jack B. Ellis

Papers

General systems from network systems: a philosophy of modelling

A generalized system-theoretic framework for modelling large scale national economic systems in dynamic, structural and spatial terms†

A control system excitation-response model for import-proportion in a national economy†