摘要:

A novel fuzzy logic controller and a fuzzy logic parameter regulator are presented in this paper for the design and implementation of a fully‐digitized speed control system of an induction motor. The former is used in tuning the proportional‐integral controller so as to yield quick response and small steady state error. The latter is used for on‐line determination of rotor time constant of induction motor under indirect field orientation so as to yield accurate speed response and avoid degrading system performance by temperature variation. A 16‐bit single‐chip microprocessor is used for reducing the number of circuit components for cost reduction and reliability enhancement. The proposed system is confirmed by both computer simulation and experimental results as having a faster response and smaller torque fluctuation than those of the system using conventional controller with a fixed rotor time constant. Aside from high performance, easy implementation via a microprocessor is identified as being yet another distinguishable feature of the system realized.

ISSN:0253-3839    

DOI:10.1080/02533839.1994.9677563

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Graph matching, set covering and partitioning problems are both theoretically and practically important in decision support systems. Numerous situations have been modeled as graph matching, set covering and partitioning problems. These situations include applications in the areas of task assignment, marriage problem, airline crew scheduling, truck deliveries or vehicle routing, political redistricting, etc. Relational database systems currently support these applications merely by providing some programming languages which are used to write the programs associated with the data. These programming languages are complete as opposed to existing query languages like SQL. These languages, since they are complete, have the usual complexity of a powerful language and lack the simplicity of query languages. This increases application development effort. Relational operators and the query language SQL are extended in this present work in order to enable these problems to be stated and solved directly by the relational database systems leading to benefits of improved data independence, increased productivity, and better performance. The relational operators are extended with six operators, i.e., match, maxmatch, cover, mincover, partition, and minpartition. Properties of these operators are described. Some of these operators may possibly take a very long time in finding a solution. Genetic algorithms are proposed. These algorithms are bounded by a polynomial time. These algorithms therefore enable DBMS to be capable of responding to queries involving proposed operators in a given time constraint. The database operations and query languages extended in this research provide a powerful tool for users as a database‐query tool which supports some decision support systems for information retrieval from a database.

ISSN:0253-3839    

DOI:10.1080/02533839.1994.9677564

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

An analysis is provided in this paper for hydrodynamic, micropolar lubrication of a misaligned journal bearing. The numerical procedure used has incorporated a cavitation algorithm, which automatically predicts film rupture and reformation in the bearings. The analysis is performed on a finite width grooved journal bearing for both starvation supply pressure and higher lubricant supply pressure inlet conditions. The larger particle and the higher viscosity of the additives delaying the film reformation boundary is confirmed by the experimental results, despite the fact that the particle size and viscosity of the additives do not influence the location of film rupture.

ISSN:0253-3839    

DOI:10.1080/02533839.1994.9677565

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The estimation of the 3‐D motion of a moving object from a sequence of images is of prime interest in computer vision. It is useful in many applications, such as scene analysis, path planning, and trajectory prediction. Two sets of feature points on a rigid object at two time instants can be used to estimate motion parameters of the object. In general, the point correspondences between two point sets are established first and then the motion parameters are estimated by solving equations which are governed by the corresponding points at these two time instants. However, the establishing of point correspondences is not trivial. In this paper, the point correspondences will be found through the technique of image processing for a trapezoid mark. Moreover, we will propose two mark‐based approaches to estimate the 3‐D motion parameters. Also in this paper, we will propose that our methods for estimating 3‐D motion parameters be applied to a new,computer‐vision based methodfor the 3‐D registration of 2‐D echocar‐diography. Basically, we expect that this method will replace the hand‐held probe‐holder mechanism in applications where visual seeing‐eye tools are used to observe the spatial location of the ultrasound probe relative to a fixed external reference point or to observe the relative motion of the probe moving between two different locations.

ISSN:0253-3839    

DOI:10.1080/02533839.1994.9677566

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Associative memory has been one of the focal points in recent neural network research. In this paper, we propose a general model for binary associative memories based on a recurrent network structure. The proposed model is based on an evolution process that is similar to the political election process. The essence of the new model lies in theweighting Junctionsand how the system evolves according to the combined, weighted contribution from all stored patterns. With appropriate choice of weighting functions, new and efficient binary associative memories can be developed quite easily. The model therefore provides a solid foundation for the design of binary associative memories suitable for future electronic and optical technology. Furthermore, many well‐known neural associative memories are shown to be special cases of this new model with appropriate reformulation of their respective evolution equation. The stability, hardware complexity, and storage capacity issues of these associative memories are also discussed.

ISSN:0253-3839    

DOI:10.1080/02533839.1994.9677567

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

An integrated approach to vision‐based autonomous land vehicle (ALV) guidance for automatic navigation and collision avoidance in building corridors and elevators is proposed. Computer vision techniques are utilized to locate an ALV in building corridors and to control it to enter elevators by the use of multiple corner points on walls. The location principle is based on matching input corner position information with a model using a distance‐weighted correlation function. Furthermore, radio equipment is employed to control the elevator operations of lifting up, lifting down, door closing, and door opening so that the ALV can enter elevators automatically. Finally, a photoelectric sensor‐based obstacle avoidance system for the ALV is developed. A real ALV was constructed as a testbed. Many successful navigation experiments confirm the effectiveness of the proposed approach.

ISSN:0253-3839    

DOI:10.1080/02533839.1994.9677568

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A model to simulate the pollutant concentrations in the reactive plume is developed. Equal partitioning of the plume into lateral cross sections enabled the mass conservation relationship to govern the concentrations in each unit cell. The model results for inert species are similar to that of the Gaussian plume model, both in ground level and airborne concentrations. For the simulated reactive plume, the model results are compared with the measured data of Janssan [6]. This model formulation give a similar downwind variation trend of the NO conversion rate, however consistently overestimated results.

ISSN:0253-3839    

DOI:10.1080/02533839.1994.9677569

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

This paper addresses “Optimal Path Estimation Method (OPEM),” a new approach for the implementation of time optimal bang‐bang control. The method is based upon feedback information obtained by estimating the distance between the present state to the switching surface defined by the optimal trajectory. A fuzzy controller is used for implementing the control logic. The OPEM controller is able to eliminate the chattering phenomenon common to most conventional trajectory access and following‐type controllers. It is shown that the system trajectory will eventually enter a finite region around the target point and will stay inside that region. The size of the final region around the target point is also determined in this paper. The advantages of the proposed method over traditional Bang‐Bang control are illustrated by the numerical simulations of a servomotor system.

ISSN:0253-3839    

DOI:10.1080/02533839.1994.9677570

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A finite element model is established for analyzing two‐layer adhesively bonded cracked plates. The element formulation is based on the Reissner‐Mindlin plate theory with an assumed variation of the transverse shear and normal stresses through the thickness of the layers. The generalized stress‐strain relationship of transverse shear stress factors and adhesive stresses to displacement of the layers is established by using a variation principle. By means of the finite element model presented herein, the cracking of adhesively bonded plates can be prevented by reasonably estimating the stress intensity factor and adhesive stresses. Numerical examples are provided to compare the stress intensity factors with those of experimental measurements found in previous research projects. This study also illustrates the effects of adhesive thickness on the stress intensity factor in the cracked layer and on the stresses in the adhesive.

ISSN:0253-3839    

DOI:10.1080/02533839.1994.9677571

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

This paper presents a new, silicon compiler‐based methodology for designing application‐specific chips. A newly developed behavioral silicon compiler called DSS is used to implement standard DSP components. This compiler includes a design specification language parser, a high‐level synthesizer and a parameterized module generator. The goal is to reduce the overall design time of DSP systems by offering the designer a complete compilation environment. Design space exploration is illustrated in examples, to show the ability of a silicon compiler to create and test many design alternatives in a very short time period. Designers using this compiler are encouraged to try several designs until a feasible one is found. Design examples are given in later sections to illustrate the synthesis result.

ISSN:0253-3839    

DOI:10.1080/02533839.1994.9677572

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor