摘要:

AbstractThe problem of reliability evaluation of phased-mission systems is encountered in systems that perform tasks within several time divided phases. Each of these phases differs by the module failure intensities and by the system reliability structure. This paper considers reliability modelling of the phased-mission with performance degradation. Each mission phase can have several subsequent phases determined by the system state. System states are characterized by some mission performance level. Performance levels include the achievement of the basic or alternative mission tasks. Transitions between phases occur at random moments. The subsequent phase durations are dependent on time spent in the previous phases.

ISSN:0228-6203    

DOI:10.1080/02286203.1996.11760287

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

AbstractThe authors present the results of simulation studies of a parallel architecture proposed for a hybrid service control point and intelligent peripheral in the Advanced Intelligent Network. The service control point and intelligent peripheral provide call-processing services and must be capable of providing a high transaction throughput with low overhead. We describe the evolution of the advanced intelligent network and show how our proposed hybrid service control point/intelligent peripheral can significantly reduce post-dial delay. Our architecture studies focus on a new class of telecommunications services referred to as personal communications services. These services are expected to be widely available and will place enormous burdens on the telephone network. Simulation studies indicate that our proposed architecture offers high transaction throughput with low delay variance and actively supports the development of new telecommunications services.

ISSN:0228-6203    

DOI:10.1080/02286203.1996.11760288

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

AbstractComputer systems that process natural languages require the creation of a database-describing lexicon with extensive information about words, and a formal representational model allowing access and data manipulation. Most research attempts to find model representation taking into account both information and its processing procedures. Among these formalisms are automata, concepts used to analyse formal languages such as designing and programming languages. Automata seem to be well-adapted tools for the representation of the observed phenomena of natural languages.

ISSN:0228-6203    

DOI:10.1080/02286203.1996.11760289

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

AbstractA new arithmetic number system based on fractional powers of two is proposed. In this system, the weight of each bit position is a power of 21/n, wheren= 1,2,3,4 ... Multiplication or division by 21/ncan be accomplished by simple shifts of the input data. Although not as simple as in conventional twos complement binary, addition and subtraction can be accomplished using simple ALU structures. Details of how this is accomplished are given, as well as an implementation of hardware structure to perform multiply-accumulate operations commonly found in neural nets and FIR filters. Applications of this arithmetic system in binary neural networks are also given.

ISSN:0228-6203    

DOI:10.1080/02286203.1996.11760290

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

AbstractA numerical model is introduced to study the effect of rotary disturbances on aircraft response. The model follows the technique proposed by the senior author for solving the coupled equations of motion of an aircraft. The general small-disturbance equations of motion are obtained as a system of linearized first-order differential equations. These equations are written in the form of a state equation. The latter equation is integrated by trapezoidal integration, which is stable for all increment sizes. The proposed numerical model simulates the aircraft response due to rotary disturbances that arise from variations in loads applied on the aircraft. Computergenerated illustrations of these responses are presented for initial pitching velocity disturbance, rolling disturbance, and yawing disturbance during straight flight. For an initial longitudinal rotary disturbance, the responses exhibit overshoots, short-period critically damped modes, and low-amplitude long-period oscillation modes for the symmetrical perturbations of the aircraft. On the other hand, a lateral initial disturbance causes heavily damped short period oscillation modes, exponentially decaying or increasing modes, and also critically damped modes for asymmetrical motion. Based on such responses, it is possible to extract the aircraft stability criteria.

ISSN:0228-6203    

DOI:10.1080/02286203.1996.11760291

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

AbstractThis paper reports the most significant and recent aspects of a wide educational activity developed by the author at the Engineering Faculty of the University of Genova, Italy, based on an integrated and user-friendly approach oriented to modelling, simulation, and identification of oil-hydraulic and pneumatic components and systems.

ISSN:0228-6203    

DOI:10.1080/02286203.1996.11760292

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

AbstractIn this paper, a computationally efficient time and transform domain model for computing discrete wavelet transform is described, and the breaking point for the filter length is derived. This result provides a guideline for choosing a computationally efficient model for a given wavelet. The implementation of wavelet transform is computationally intensive, as the number of computations required increases with the number of octaves. Various methods are applied to reduce the number of operations necessary for calculations of wavelet coefficients. Improved computational efficiency of transform domain model is a result of replacing subsequent transformations, decimations, or interpolations and inverse transformations by simple additions or replications of transform values respectively. Computational complexity per octave for transform domain algorithm is compared with the complexity of direct convolution and modified lattice. A modified lattice structure with commuted sampling rate conversion is found to be significantly more efficient than direct convolution model. Transform domain filtering with incorporated sampling rate conversion leads to a computationally efficient model for computing wavelet coefficients for filters of length 20 or longer (longer wavelet), whereas modified lattice results in better efficiency for shorter filter length (shorter wavelet). Simulation results are presented to illustrate this breaking point filter length and tradeoffs between computational complexity of transform domain and lattioe model.

ISSN:0228-6203    

DOI:10.1080/02286203.1996.11760293

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

AbstractThis paper uses min/max graphs to study the aggregate production planning model. The model is formulated and computerized as the deterministic Unear dynamic programming problem; uncertainty is modelled by assuming that coefficients of the problem are some representations of stochastic processes. Basic elements of the min/max graph theory are reproduced. A central position is occupied by the notion of approximation of the graph. The graph represents a set of solutions (variants) of the problem obtained in a procedural way. The strategy of the variants' generation decides about the semantics of the min/max graph, aspects and accuracy of the study of the model, and the usefulness of the idea for the particular decision problem. The study was carried out with respect to hard predictable parameters of the model, such as prices, demand, and costs. Some assumptions regarding trends of those parameters are made. Results were obtained with the stand-alone UV module that supports all manipulations and the min/max graph itself.

ISSN:0228-6203    

DOI:10.1080/02286203.1996.11760294

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

AbstractThe purpose of this study is to establish a proper system model for deep-hole drilling process. A basic 1-DOF and an extended 2-DOF system model are proposed. Dynamic equations for the corresponding part of the system are given. Transfer functions are derived, and for the extended 2-DOF model the state space formulation is given. As well, a generalized stability criterion suitable for all machining process is proposed to enable a stability investigation by construction of stability chart. As the analysis conducted in this work is valid for the whole range of overlap factor 0≤μ≤1, the approach has significance far beyond the specific deep-hole drilling process discussed.

ISSN:0228-6203    

DOI:10.1080/02286203.1996.11760295

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

AbstractIn this paper, the authors propose a general statistical definition of acceleration factor k and derive an unbiased estimator (W-P) of k for the gamma distribution. Six ratio estimators from the sampling survey literature–simple, Quenouille's, Beale's, Tin's, Jackknife, and Fieller's–are modified to estimate the acceleration factor. These estimates, based on the assumption of independent samples in accelerated testing, are compared in terms of their bias and computational convenience. The W-P estimator appeals to be the most promising for the gamma distribution, especially in cases of unequal sample sizes. Quenouille's, Beale's, Tin's, and Jackknife estimators are generally attractive, although they can be applied only in cases of equal sample sizes from the two stresses conditions. The authors show that the simple estimator lias upper bias for the ganuna distribution, and that Fieller's estimator is not satisfactory.

ISSN:0228-6203    

DOI:10.1080/02286203.1996.11760296

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor