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1.
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   

2.
The multivariable approach to the synthesis of networks composed of a finite number of uniform lossless transmission lines, commensurable or incommensurable, and lumped passive elements is verified by showing that the multivariable rational matrix, W(λ0,λ1, .. ,λn) is bounded real in (n + 1) complex variables if and only if W is bounded real in p after substituting, λ0 = α0p + β0 and λi = tanh (αip + βi) for λi (1?i?n) where all the α's and β's are nonnegative and arbitrary, except for being not simultaneously zero in like indexed pairs. Consequences of this result are discussed.  相似文献   

3.
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   

4.
A simple theory is presented for decoupling a pair of lossless coupled nonuniform transmission lines (CNUTL), with a common return and supporting TEM waves, into two lossless nonuniform transmission lines (NUTL). This theory is independent of the port terminations, symmetry conditions, etc. The method directly relates the line parameters of the lossless CNUTL's to those of the decoupled lines and vice versa; further, the matrix parameters of the CNUTL's as a four-port are explicitly expressed in terms of those of the decoupled lines as two-ports. This theory is then utilized to study the applications of CNUTL's as directional couplers.It is shown that for CNUTL's to behave as a codirectional coupler, each of the decoupled lines should be a proportional line, while for contradirectional coupler action, the two decoupled lines have to be duals of each other. The coupling response of the codirectional coupler is found to be periodic, while the phase shift between coupled and transmitted signals varies linearly with frequency. The coupling response of various contradirectional couplers with smooth transition at one of the ends, for which the decoupled lines are “basic NUTL's with hyperbolic solutions”, are studied in detail. It is shown that all these couplers have a high-pass response and that the CNUTL's with “hyperbolic cosine squared lines” as decoupled lines have the best response of all the CNUTL's considered.  相似文献   

5.
The law is a near perfect application area for knowledge representation. Legal knowledge representation is needed in conceptual legal information retrieval systems and in legal reasoning systems. We review the knowledge representation aspects of four such systems: Waterman and Peterson's Legal Decisionmaking System, Hafner's Legal Information Retrieval System, McCarty's TAXMAN, and the deBessonet representation of the Louisiana Civil Code (CCLIPS).  相似文献   

6.
Topological analysis of the signal flow graph associated with the hybrid system of equations for a linear active or passive electrical network for which the element admittance matrix exists and is diagonal is considered. First, the term cancellation which occurs in Mason's topological formulas is investigated. Necessary and sufficient conditions on the signal flow graph topology such that a term in the expansion of the graph determinant and cofactors either cancels out with another term in the expansion or does not cancel are established. Properties of the associated network which result in non-cancelling terms are given and the number of non-cancelling terms is determined. Second, new signal flow graph topological formulas for the graph determinant and cofactors are proven. These formulas are such that no term cancellation occurs and are readily adaptable to computer implementation. In addition, the number of terms in these formulas is independent of the network tree used to formulate the signal flow graph. Examples are given to illustrate the new formulas.  相似文献   

7.
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   

8.
The probability of wheel climb commencing is calculated using Nadal's formula as a basis. In particular, the functional form of Nadal's formula is maintained with normal probability density functions used to describe the two arguments in Nadal's formula, namely contact plane angle and coefficient of friction at the contact point. The theoretical value of the probability of wheel climb commencing for a given lateral/vertical force ratio value at the wheel flange–railhead interface is then compared with experimental results for positive angles of attack. Theoretical results for negative angles of attack are generated for several cases.  相似文献   

9.
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10.
Agricultural research is mostly a public undertaking. In Israel, as in many other countries, farmers participate in the finance of research through taxes imposed by farm organizations on the marketed products. Farmers contribution ranges from 8% of research outlay in tomatoes to 79% in cotton. Strength of organization and ease of collection were the major factors affecting this share. In general, as inflation eroded the real value of government's finance, the farmers increased their share.Representatives of farmers' organization participate in the bodies that approve grants to proposed research projects. It was found that the higher the share of farmers' finance the larger the part of short-term research directed at immediate outcomes and the smaller the part of long-term, more basic research.The tendency of the farmers to prefer short-term, applicable research may reflect both their familiarity with practical problems and a comparatively high degree of risk aversion.It is not clear how farmers' participation in the direction of research, which is based on their financial contribution, affects the efficiency of resource allocation to the agricultural sciences.  相似文献   

11.
A set of the block pulse functions is applied to solve the Fredholm's and the Volterra's integral equations of the second kind. An algebraic equation in matrix form which is equivalent to the solution of the integral equation is developed. The approximate results are easily obtained by a few computations. An accurate solution canbe evaluated in a digital computer by solving the algebraic equation. Two examples are given.  相似文献   

12.
The shakeout period after the emergence of a dominant design is very important to technology followers and niche market producers, who need adjust to significant changes in the competitive landscape. We posit that such innovating firms use strategic signals that address technical-, market-, and standards-uncertainty associated with their innovations to communicate with market participants to reduce participants' perceived uncertainties associated with the innovative products. Studying technology followers and niche market producers in the personal computer industry during its 1982–1989 shakeout period, we found that technology followers and niche market producers differ in their use of technical-, market-, and standards-related signals. Additionally, using event study methodology, we find that technology followers' strategic signals have significant positive impacts on both their own and other followers' stock prices. Meanwhile, niche market producers' strategic signals have significant positive impacts on their own stock prices, but not significant impacts on other niche market producers and technology followers' stock prices.  相似文献   

13.
This paper challenges the meaningfulness of precision and recall values as a measure of performance of a retrieval system. Instead, it advocates the use of a normalised form of Shannon's functions (entropy and mutual information). Shannon's four axioms are replaced by an equivalent set of five axioms which are more readily shown to be pertinent to document retrieval.The applicability of these axioms and the conceptual and operational advantages of Shannon's functions are the central points of the work.The applicability of the results to any automatic classification is also outlined.  相似文献   

14.
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15.
Sweden's technological development based on big science supporting high politics is turning to more welfare-oriented technologies. The tension between the university reform performed by an inward-looking government and industrial innovation carried out by an outward-looking business community is discussed.The paper covers the time span of the quiet postwar years, the attempt to institutionalize science policy in the 1960's and the sectoral approach to science and technology advocated in the 1970's. The implications of the polarization of science policy between the government and the technological community at a time of European integration is discussed.  相似文献   

16.
A simplified model of the hysteresis motor is introduced and analyzed; field analysis is undertaken at hand of Maxwell's stress tensor and Poynting's theorem. The suggested approach provides deeper insight into the power interchange process between stator and rotor.  相似文献   

17.
A paper by Macagno (3) in this Journal is discussed. The origin of the concept of physical dimensions is traced back to ideas previously used in analytic geometry. Descartes' use of the word “dimension” in the study of physical magnitudes is shown to have properties completely different from Fourier's dimensions, being therefore unimportant to the evolution of dimensional analysis. It is also shown that the principle of homogeneity was used in the derivation of physical equations sixty years prior to the publication of Fourier's work, and that the latter was aware of this paper, that may be considered the earliest publication on dimensional analysis.  相似文献   

18.
In a seminal article on question negotiation, Taylor outlines four levels of question formulation which pertain to the client-information professional interview session. The literature which supports Taylor's theory is covered. It is proposed that Taylor's four levels may be inadequate for describing question negotiation in the online presearch interview. An altered model is given with suggestions for testing the model in the online environment. Some recommendations concerning the importance of discovering such a model are offered.  相似文献   

19.
Instead of the commonly accepted inverse square law, Lotka's original formulation was based on a more general inverse power law: xn·y = c. The exponent and the constant must be estimated from the given set of author productivity data. A step-by-step outline is presented for testing the applicability of Lotka's law. Steps include the computation of the values of the exponent and the constant based on Lotka's method, and the test for significance of the observed frequency distribution against the estimated theoretical distribution derived from Lotka's formula.  相似文献   

20.
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   

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