Abstract
We argue that in order to exploit both Independent And-and Or-parallelism in Prolog programs there is advantage in recomputing some of the independent goals, as opposed to all their solutions being reused. We present an abstract model, called the Composition-tree, for representing and-or parallelism in Prolog programs. The Composition-tree closely mirrors sequential Prolog execution by recomputing some independent goals rather than fully re-using them. We also outline two environment representation techniques for And-Or parallel execution of full Prolog based on the Composition-tree model abstraction. We argue that these techniques have advantages over earlier proposals for exploiting and-or parallelism in Prolog. © 1993 Ohmsha, Ltd. and Springer.

Abstract
The performance of frequency-modulated (FM) subcarrier-multiplexed systems is assessed using Volterra series analysis to model laser nonlinear distortion accurately. The intermodulation-power spectral density and the carrier-to-intermodulation ratio are then determined. The performance of these systems is investigated by considering all noise contributions: intermodulation and relative intensity noise in the transmitter and receiver thermal and shot noise. Optimum performance is also identified. A 62-channel FM video system occupying the bandwidth of 2.7-5.2 GHz provides an illustrative example.

Abstract
The paper describes the results to date of the RACE project R2005. The project addresses the optical generation and fibre delivery of mm-wave signals for future mobile radio and remote customer access connections. The authors identify potential application areas and appropriate performance targets for such fibre/mm-wave systems. The major issue identified is the need to achieve low-cost antenna units due to the large number of such units that would be required; this arises from the limited propagation distances achieveable at mm-wave frequencies. A brief review of current optical methods for the generation of mm-waves allows the identification of the inadequacies of these techniques and leads to a description of a new method, developed for the project, that overcomes most of the disadvantages outlined earlier.

Abstract
In this paper one proposes that the concept of risk should be central in a distribution planning methodology, and that the procedures and models adopted should be used to take that factor in account and assess the robustness and exposure of the solution studied. It is also argued that this purpose is best served if a multicriteria approached is adopt as much as possible, keeping explicit record of the values of the serval attributes that may classify the goodness of a solution.

Abstract
In this paper, system component reinforcements are analyzed from the perspective of their impact in increasing flexibility in system design. The proposed framework integrates a fuzzy optimal power flow model through which one can derive, as a function of load uncertainties, possibility distributions for generation, power flows and power not supplied. Exposure and robustness indices, based on risk analysis concepts, are defined. These indices can be used to rank the expansion alternatives, giving the planner insight to system behavior in face of adverse futures. Their use in conjunction with investment assessments is proposed as a necessary step in a decision making methodology.

Abstract