共查询到20条相似文献，搜索用时 765 毫秒
1.
In this paper, we derive discrete versions of Green's identities (which appear in the study of potential field theory) as direct consequences of applying Tellegen's Theorem to the Graph—Theoretic Field Model (GTFM) of a field. The procedure herein is in marked contrast to the existing procedures where Green's Identities are derived from the Divergence Theorem by using some strictly mathematical operations. In particular, Green's third identity, which is the starting point formulation for the Boundary Integral Method, is singled out for special attention in terms of its discrete counterpart in the Graph—Theoretic Field Model. The first discrete identity is used to establish certain properties of solutions for the GTFM and a limiting process is applied to the three discrete identities to derive the traditional vector-calculus forms of Green's identities. 相似文献
2.
This paper deals with the computation of the values of two functionals which are defined over the sample paths of a randomly rotating rigid body. It is assumed that the body is subjected to two different kinds of perturbation. The first kind of perturbation is represented by the standard Wiener process and the second kind by a homogeneous process with independent increments, finite second-order moments, mean zero and no continuous sample functions. In order to measure quantitatively the stochastic stability of the body's motion, two functionals are defined over its sample paths. It is shown that each of these functionals is a solution to a corresponding partial integro-differential equation. A numerical procedure for the solution of these equations is suggested, and its efficiency and applicability are demonstrated with examples. 相似文献
3.
This paper introduces a polynomial operator called the DT-polynomial as a novel approach to network flow problems. The class of networks dealt with is time-varying in the sense that the capacity, cost, and travel-time of each edge may vary in discrete time. The Dt-polynomial is a polynomial in two operators, D (delay) and T (time), which is used for describing the time-varying transmission characteristics. The paper starts with the mathematics involving the DT-polynomials. A new shortest arrival route algorithm is presented, and its computational complexity is found to be favorable in comparison with others such as Dijkstra's method and the potential method derived from Ford-Fulkerson's technique. Furthermore, a dynamic flow problem is formulated and analyzed in terms of DT-polynomials, and a latest-departure earliest-arrival schedule is given. Finally, a modified DT-polynomial is applied to digital filter networks. 相似文献
4.
Robert Plonsey 《Journal of The Franklin Institute》1974,297(5):317-324
This paper considers the properties of scalar fields which satisfy Laplace's equation and which are either discontinuous or have discontinuous normal derivatives across some arbitrary surface. It is shown that expressions for the volume conductor fields of bioelectric sources can be readily obtained from the aforementioned relations. This procedure is simple and, in addition, preserves physical insight. 相似文献
5.
《Journal of The Franklin Institute》2022,359(15):8188-8200
This work investigates the improved stability conditions for linear systems with time-varying delays via various augmented approaches. Some augmented approaches are augmented Lyapunov-Krasovskii functionals, augmented zero equalities, and the augmented zero equality approach. At first, by constructing augmented Lyapunov-Krasovskii functionals including the state vectors which were not considered in the previous works and augmented zero equalities, a stability criterion is proposed in the forms of linear matrix inequalities. Through the proposed Lyapunov-Krasovskii functionals and an additional functional derived from the integral inequality, a slightly improved result is derived. The proposed results do not consider the increase in the computational complexity to achieve a larger delay bound. So, by applying the augmented zero equality approach, which is a method of grafting the proposed augmented zero equality proposed in Finsler Lemma, to the proposed result, an enhanced stability result was derived. Also, the computational complexity is reduced by appropriately adjusting any vector of the integral inequality utilized in the proposed criteria. By applying some numerical examples to the proposed conditions, the effectiveness and superiority of the results are confirmed. 相似文献
6.
Based on Schussler's theorem, some new properties of polynomials containing zeros inside the unit circle are obtained. These properties give rise to (i) a new stability test of 1-D discrete systems, and (ii) some necessary coefficient conditions that have to be satisfied by the denominator polynomial of a stable 1-D discrete system. 相似文献
7.
Gérard A. Maugin 《Journal of The Franklin Institute》1978,305(1):11-26
This paper first presents a fully covariant formulation of Maxwell's equations in matter in the general relativistic framework. Although covariant, this formulation uses only essentially spatial four-vector fields and places in evidence the kinematical couplings (vorticity) and inertial effects (curvature of worldlines) which appear in Maxwell's equations for matter. Using a scaling of these equations enables one to construct covariant “quasi-electrostatic” and “quasi-magnetostatic” approximations. Theformer is used to establish the equations that govern piezoelectric gravitational-wave detectors. Furthermore, if a pyroelectric crystal is used in this type of device, then Gauss' law is shown to be modified and contains a contribution due to the incident gravitational perturbation. 相似文献
8.
A unified approach to stability analysis of feedback control systems with pulse-width modulators is discussed. The proposed procedure is developed on the basis of the discrete analog of Lyapunov's method, with no limiting hypothesis on the structure of the controlled plant and of the modulation law.The analysis is exemplified particularly for lead-type PWM control systems. Significant plant classes are investigated, and the critical values of parameters in a closed form are determined which assure asymptotic stability of the steady-state solution, whatever the reference input may be. 相似文献
9.
10.
This paper is devoted to stability analysis of discrete-time delay systems based on a set of Lyapunov–Krasovskii functionals. New multiple summation inequalities are derived that involve the famous discrete Jensen?s and Wirtinger?s inequalities, as well as the recently presented inequalities for single and double summation in [16]. The present paper aims at showing that the proposed set of sufficient stability conditions can be arranged into a bidirectional hierarchy of LMIs establishing a rigorous theoretical basis for the comparison of conservatism of the investigated methods. Numerical examples illustrate the efficiency of the method. 相似文献
11.
Leon Y. Bahar 《Journal of The Franklin Institute》1975,299(1):33-41
The two-dimensional, plane stress problem of linear elasticity is analyzed within a state space framework. The medium considered is homogeneous and isotropic. Vlasov's mixed formulation of elasticity is used throughout. The field equations are derived in closed form, thus avoiding Vlasov's intermediate infinite series solution. Finally, all the properties of the transfer matrix are shown to follow directly from embedding the problem into a state space setting. 相似文献
12.
M.G. Marieta 《Journal of The Franklin Institute》1976,301(4):317-333
The equations of motion for perfectly mechanical systems which are restricted to satisfy given constraints are derived through the Lagrangian formulation for continuous media. Hamilton's equations for this situation are derived, and the equations for the balance of energy and angular momentum are generated from fundamental principles. These equations are all specialized to the example of a conductor which is vibrating under Aeolian excitation. Various models for the Hamiltonian density and the constraint energy density due to the wind energy input are also discussed. 相似文献
13.
Zeynab Soltani Batool Zareie Farnaz Sharifi Milani Nima Jafari Navimipour 《The Journal of High Technology Management Research》2018,29(2):237-246
Customer Relationship Management (CRM) is a very important growing business practice in today's environment. It is used for managing the interaction between a company and its future and current customers. CRM approach's task is analyzing data about the history of customers with a company. It focuses on a way to retain customers, therefore it helps the growth of sales. This leads to improvement of company's business relationship with customers. Current study's goal is to determine how technology, organizational capability, customer orientation, and customer knowledge management influence CRM success. We try to see that how the performance of an organization is affected by the achievement of CRM. For testing the hypotheses, Partial Least Squares Structural Equation Modeling (PLS-SEM) was adopted. Results have indicated that the success of CRM is highly influenced through “information technology use”, also “customer orientation”, “organizational capability”, and “customer knowledge management” are related to CRM success. Finally, along with the future research avenues and limitations, study implications and findings are discussed. 相似文献
14.
Herbert J. Carlin Pier Paolo Civalleri Jeffrey C. Hantgan 《Journal of The Franklin Institute》1981,311(4):209-230
A general procedure is outlined for obtaining single or coupled transmission line models to represent the propagation of surface wave modes in conductively unshielded dielectric waveguides. The procedure uses a homogeneous electrically or magnetically walled waveguide having the same dimensions as the dielectric of the surface waveguide, to produce a set of orthogonal eigenfunctions. These eigenfunctions are projected upon Maxwell's equations resulting in a system of transmission lines coupled together through a wave immittance, which represents the ratio of a longitudinal and a transverse field component at the dielectric-air interface. Examples are given for various modes of the dielectric slab and the dielectric rod, in particular the HE1n modes for the latter. The transmission line models derived for these examples consist of a single trasmission line found directly by projection or reduced from a coupled transmission line model by port elimination, or of two transmission lines coupled together. All circuit models derived preserve the basic properties of surface waves (e.g. no solution below cut-off), and any of the single line models can be solved to give explicit approximate algebraic formulae for the propagation constant as a function of frequency. Numerical results show that the dispersion curves calculated from the models versus exact values are generally excellent over the entire frequency spectrum. 相似文献
15.
This paper presents a novel integrated guidance and control strategy for homing of unmanned underwater vehicles (UUVs) in 5-degree-of-freedom (DOF), where the vehicles are assumed to be underactuated at high speed and required to move towards the final docking path. During the initial homing stage, the guidance system is first designed by geometrical analysis method to generate a feasible reference trajectory. Then, in the backstepping framework, the proposed trajectory tracking controller can achieve all the tracking errors in the closed-loop system convergence to a small neighbourhood of zero. It means that the vehicle's dynamics are consistent with the reference trajectory derived in the previous step. To demonstrate the effectiveness of the proposed guidance and control strategy, the complete stability analysis used Lyapunov's method is given in the paper, and simulation results of all initial conditions are presented and discussed. 相似文献
16.
The properties of the hysteresis machine are analyzed on the basis of a cylindrical model. The electromagnetic field in the various regions of the motor is derived by field-theoretical methods (such as Maxwell's equations and Poynting's theorem), and the resulting parameters are applied in turn in determining torques and other relevant quantities. Three limiting particular cases of special interest are examined. 相似文献
17.
The Canadian federal government, anxious to stimulate innovation, announced recently a policy objective for the economy: the attainment of industrial research expenditures reaching 1.5 percent of the gross national product. The proposed substantial increase over the current level is rationalized by comparison with economy-wide research intensities (GERD/GNP) in other OECD countries.This paper questions the economic validity and policy relevance of international aggregate comparisons. It argues that inter-country comparisons should take place at individual industry levels where technologies are similar and proposes a methodology for formulating R&D spending targets of this kind. The procedure is to estimate a model of the determinants of R&D intensity with data from several “criterion countries” and employ the results to “predict” a specific industry's research intensity in another country.In this paper such a model is formulated for the pharmaceutical industry of seven OECD countries. Plausible parameter estimates are derived and used to “forecast” the research intensity of the Canadian pharmaceutical industry. It is found that given the predominance of foreign ownership, the nature of patent protection and the level of other relevant variables in Canada, the performance of this sector is much above the OECD-derived standard; this Canadian industry presumably does not require governmental attention to its R&D activities. 相似文献
18.
Charles Cole 《Information processing & management》1998,34(6):709-720
The research examines the notion that the principles underlying the procedure used by doctors to diagnose a patient's disease are useful in the design of “intelligent” IR systems because the task of the doctor is conceptually similar to the computer (or human) intermediary's task in “intelligent information retrieval”: to draw out, through interaction with the IR system, the user's query/information need. The research is reported in two parts. In Part II, an information retrieval tool is described which is based on “intelligent information retrieval” assumptions about the information user. In Part I, presented here, the theoretical framework for the tool is set out. This framework is borrowed from the diagnostic procedure currently used in medicine, called “differential diagnosis”. Because of the severe consequences that attend misdiagnosis, the operating principle in differential diagnosis is (1) to expand the uncertainty in the diagnosis situation so that all possible hypotheses and evidence are considered, then (2) to contract the uncertainty in a step by step fashion (from an examination of the patient's symptoms, through the patient's history and a physical (signs), to laboratory tests). The IR theories of Taylor, Kuhlthau and Belkin are used to demonstrate that these medical diagnosis procedures are already present in IR and that it is a viable model with which to design “intelligent” IR tools and systems. 相似文献
19.
A stepwise fault analysis procedure for the class of digital circuits known as Linear Sequential Circuits (LSC) is presented where the LSC is defined over a finite field. The development of a spectral theory for this class of systems provides a mechanism for exploiting the LSC's memory. This, in general, allows fewer test inputs than would be required for fault analysis of a memoryless circuit of similar complexity. 相似文献
20.
F.M. Reza 《Journal of The Franklin Institute》1984,317(2):57-71
The scalar versions of Schwarz's Lemma have been extensively employed in the classical development of the synthesis of lumped RLC driving-point impedance function. A vector space generalization of Schwarz's Lemma, particularly suitable for application to linear passive n-port impedance functions, is derived in this paper. The concept of power dominant networks is introduced and a number of power inequalities derived. 相似文献