The behavior of the two-point crossover operator, on candidate solutions to an optimization problem that is restricted to integer values and by some set of constraints, is investigated theoretically. This leads to the...
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The behavior of the two-point crossover operator, on candidate solutions to an optimization problem that is restricted to integer values and by some set of constraints, is investigated theoretically. This leads to the development of new genetic operators for the case in which the constraint system is linear. The computational difficulty asserted by many optimization problems has lead to exploration of a class of randomized algorithms based on biological adaption. The considerable interest that surrounds these evolutionary algorithms is largely centered on problems that have defied satisfactory illation by traditional means because of badly behaved or noisy objective functions, high dimensionality, or intractable algorithmic complexity. Under such conditions, these alternative methods have often proved invaluable. Despite their attraction, the applicability of evolutionary algorithms has been limited by a deficiency of general techniques to manage constraints, and the difficulty is compounded when the decision variables are discrete. Several new genetic operators are presented here that are guaranteed to preserve the feasibility of discrete aspirant solutions with respect to a system of linear constraints. To avoid performance degradation as the probability of finding a feasible and meaningful information exchange between two candidate solutions decreases, relaxations of the modified genetic crossover operator are also proposed. The effective utilization of these also suggests a manipulation of the genetic algorithm itself, in which the population is evanescently permitted to grow beyond its normal size.
The problem of managing replicated copies of data in a distributed system has received a lot of attention. Both token-passing and quorum consensus methods for managing replicated data have their drawbacks. Token-based...
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The problem of managing replicated copies of data in a distributed system has received a lot of attention. Both token-passing and quorum consensus methods for managing replicated data have their drawbacks. Token-based solutions, although being able to manage the concurrence with very low overheads, suffer in both reliability and concurrence due to the fact that there only exists a single token. However, although quorum-based protocols can provide higher levels of reliability by committing updates to a set of nodes, as well as being able to provide for concurrence in the form of reads, they do this at costs at orders of magnitude greater than that of token-passing algorithms. In this paper, we present a protocol that can be seen as ''multitoken'' or ''dynamic quorum,'' which uses aspects of both token-passing and quorum-based protocols to provide not only the reliability and concurrence provided by quorum-based protocols, but at the cost of a token-based protocol.
The computation of the optical flow field from an image sequence requires the definition of constraints on the temporal change of image features. In this paper, we consider the implications of using multiple constrain...
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The computation of the optical flow field from an image sequence requires the definition of constraints on the temporal change of image features. In this paper, we consider the implications of using multiple constraints in the computational schema. In the first step, it is shown that differential constraints correspond to an implicit feature tracking. Therefore, the best results (either in terms of measurement accuracy, and speed in the computation) are obtained by selecting and applying the constraints which are best ''tuned'' to the particular image feature under consideration. Considering also multiple image points not only allows us to obtain a (locally) better estimate of the velocity field, but also to detect erroneous measurements due to discontinuities in the velocity field. Moreover, by hypothesizing a constant acceleration motion model, also the derivatives of the optical flow are computed. Several experiments are presented from real image sequences.
Mobile objects are programs passed between distributed information servers for execution on remote sites within a limited environment. We describe the MHEG virtual machine specification which supports mobile code in a...
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Mobile objects are programs passed between distributed information servers for execution on remote sites within a limited environment. We describe the MHEG virtual machine specification which supports mobile code in a heterogeneous environment. MHEG VM is suitable for integration in many different distributed information systems, including the WWW. We briefly describe the possible integration of the MHEG VM with the HyOctane hypermedia system. We conclude this paper by discussing various issues associated with the design of robust mobile code systems. Copyright (C) 1996 Elsevier science Ltd
Lack of bandwidth has been shown to be a major impediment to achieving realism in large scale virtual worlds with many interacting entities. Recent projects that have addressed this problem have, for the most part, be...
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This paper describes the motivations for and main features of Tigger - a framework for the construction of a family of object-support operating systems that can be tailored for use in a variety of different applicatio...
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Lack of bandwidth and network latency are known to be major impediments to achieving realism in distributed virtual world (vw) applications with a large number of, potentially geographically dispersed, entities. This ...
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ISBN:
(纸本)9781450373395
Lack of bandwidth and network latency are known to be major impediments to achieving realism in distributed virtual world (vw) applications with a large number of, potentially geographically dispersed, entities. This paper describes a combination of techniques that we are using to overcome these twin problems. The techniques described are intended to reduce both the volume and frequency of communication between the entities that make up the virtual world and include the use of anonymous event-based communication with notify constraints, scoping of event propagation with zones, and use of predictive approaches to replica management. Each of these techniques is described in turn.
A Health Care Establishment (HCE) is an establishment where medical services are rendered. The above services are provided by the health care personnel. The infrastructure of a HCE may include Information Technology (...
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distributed multimedia information systems (DMIS) are concerned with multimedia information processing, multimedia information models, and multimedia information delivery in distributed computing environments. Today t...
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Managing modern information systems becomes increasingly complex. Therefore, the need for flexible mechanisms which assist system managers is evident. Management policies are means to control object behaviour. Conside...
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