Showing papers on "Binary constraint published in 1986"
Proceedings Article•
11 Aug 1986TL;DR: It is proved that the problem solved by discrete relaxation is log-space complete for P (the class of polynomial time deterministic sequential algorithms), which implies that discrete Relaxation is inherently sequential and it is unlikely that it can solve the polynometric time version of the consistent labelling problem in logarithmic time by using only a polynomatic number of processors.
Abstract: Constraint satisfaction networks have been shown to be a very useful tool for knowledge representation in Artificial Intelligence applications. These networks often utilize local constraint propagation techniques to achieve global consistency (consistent labelling in vision). Such methods have been used extensively in the context of image understanding and interpretation, as well as planning, natural language analysis and commonsense reasoning. In this paper we study the parallel complexity of discrete relaxation, one of the most commonly used constraint satisfaction techniques. Since the constraint propagation procedures such as discrete relaxation appear to operate locally, it has been previously believed that the relaxation approach for achieving global consistency has a natural parallel solution. Our analysis suggests that a parallel solution is unlikely to improve by much the known sequential solutions. Specifically, we prove that the problem solved by discrete relaxation is log-space complete for P (the class of polynomial time deterministic sequential algorithms). Intuitively, this implies that discrete relaxation is inherently sequential and it is unlikely that we can solve the polynomial time version of the consistent labelling problem in logarithmic time by using only a polynomial number of processors. Some practical implications of our result are discussed.
30 citations
TL;DR: In this article, a control problem of designing a cascade compensator which minimizes the effect of the disturbance inputs or the weighted sensitivity H ∞ -norm on the plant output subject to the constraint of a sensor-noise characteristic or robust stability of the closed-loop system is addressed.
Abstract: This note is concerned with a control problem of designing a cascade compensator which minimizes the effect of the disturbance inputs or the weighted sensitivity H^{\infty} -norm on the plant output subject to the constraint of a sensor-noise characteristic or robust stability of the closed-loop system Lower and upper bounds are presented
5 citations
1 Apr 1986
TL;DR: A new approach to the design of narrowband antenna array processors is proposed that allows a wide variety of possible errors to be incorporated in the problem formulation and leads to a robust optimum weight vector.
Abstract: A new approach to the design of narrowband antenna array processors is proposed. The new approach allows a wide variety of possible errors to be incorporated in the problem formulation and leads to a robust optimum weight vector. The new approach can be used to make the optimum system robust against channel phase errors, array geometry errors and pointing errors, to name a few. Initially a general quadratic constraint on the weights is developed. However, it is then shown that the quadratic constraint can be replaced by linear constraints or at most linear constraints plus norm constraint. These latter set of constraints are no more complex than those required for designs which do not incorporate robustness features explicitly. The new optimum processor can be implemented adaptively.
4 citations
1 Aug 1986
TL;DR: A method of representing a system of cooperating processes with state variables and constraints between them is introduced, borrowed from Concurrent Prolog but the process reduction is performed nondeterministically.
Abstract: Constraints solving theory is a practical approach to the knowledge based CAD/CAM systems. Previously we presented a computation model, the Method of Constraint Reduction based on the logic programming notion. As an application of the model to the design problem in time domain such as timing design or verification of a sequence controller, a method of representing a system of cooperating processes is introduced. This method is characterized as follows. The idea of process reduction is borrowed from Concurrent Prolog but the process reduction is performed nondeterministically. The method treats a system of processes with state variables and constraints between them.