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The study investigated the effects of anti-speeding messages based on protection motivation theory (PMT) components: severity, vulnerability, rewards, self-efficacy, response efficacy, and response cost, on reported speeding intentions. Eighty-three participants aged 18–25 years holding a current Australian driver's license completed a questionnaire measuring their reported typical and recent speeding behaviors. Comparisons were made between 18 anti-speeding messages used on Australian roads and 18 new anti-speeding messages developed from the PMT model. Participants reported their reactions to the 36 messages on the perceived effectiveness of the message for themselves and for the general population of drivers, and also the likelihood of themselves and other drivers driving within the speed limit after viewing each message. Overall the PMT model-derived anti-speeding messages were better than jurisdiction-use anti-speeding messages in influencing participants’ reported intention to drive within the speed limit. Severity and vulnerability were the most effective PMT components for developing anti-speeding messages. Male participants reported significantly lower intention to drive within the speed limit than did female participants. However, males reported significantly higher intention to drive within the speed limit for PMT-derived messages compared with jurisdiction-based messages. Third-person effects were that males reported anti-speeding messages to be more effective for the general driving population than for themselves. Females reported the opposite effect – that all messages would be more effective for themselves than for the general driving population. Findings provided support for using a sound conceptual basis as an effective foundation for anti-speeding message development as well as for evaluating proposed anti-speeding messages on the target driver population.  相似文献   

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In this paper the optimal shapes and fiber architectures of non-geodesics-based domes for pressure vessels are determined upon the condition of equal shell strains. Based on the continuum theory and the non-geodesic law, the system of differential equations governing the optimal meridian profiles is derived. A specific function is chosen to describe the slippage coefficient distribution for the desired non-geodesic path, in order to ensure C1 continuity of the roving paths when passing the dome–cylinder conjunction. Next, the meridian profiles are determined for various material anisotropies; the related winding angle developments of non-geodesic trajectories are also presented. The performance factors of non-geodesics-based optimal domes are obtained using various slippage coefficients and polar opening radii. The results show that the structural efficiency of the dome improves with increasing slippage coefficient. It is concluded that the non-geodesics-based dome designed using the present method gains better performance than the one relying on geodesics.  相似文献   

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The electronic structures and formation enthalpies of compounds in the Li–N–H system have been studied by using the density functional theory. In order to evaluate the competition between each reaction in the system, the chemical potential phase diagrams of compounds in the Li–N–H system have been computed and discussed. Our calculations show that for LiNH2, Li+ combines with [NH2]- by an ionic bond. For Li2NH, the N–H bond displays covalent characteristics. The calculated formation enthalpy of compounds in the Li–N–H system is in agreement with previous results, the LiNH2 is −212.27 kJ mol−1, LiH is −91.66 kJ mol−1, Li2NH is −243.14 kJ mol−1, Li4NH is −309.72 kJ mol−1, Li3N is −189.11 kJ mol−1, and NH3 is −102.27 kJ mol−1, respectively. Using the chemical potential phase diagrams, six reversible reactions are discussed. It is found that Li4NH takes part in the three reversible reactions and some NH3 formed in the system react with other compounds in the Li–N–H system. These reversible reactions are confirmed by the proposed mechanism from experiments.  相似文献   

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Recently, we introduced the framework for signal processing on a nonseparable 2-D hexagonal spatial lattice including the associated notion of Fourier transform called discrete triangle transform (DTT). Spatial means that the lattice is undirected in contrast to earlier work by Mersereau introducing hexagonal discrete Fourier transforms. In this paper we derive a general-radix algorithm for the DTT of an n × n 2-D signal, focusing on the radix-2 × 2 case. The runtime of the algorithm is O(n 2 log(n)), which is the same as for commonly used separable 2-D transforms. The DTT algorithm derivation is based on the algebraic signal processing theory. This means that instead of manipulating transform coefficients, the algorithm is derived through a stepwise decomposition of its underlying polynomial algebra based on a general theorem that we introduce. The theorem shows that the obtained DTT algorithm is the precise equivalent of the well-known Cooley–Tukey fast Fourier transform, which motivates the title of this paper.
It is with great sadness that the authors contribute this paper to this special issue in memory of their former PhD advisor Thomas Beth. Beth was an extremely versatile researcher with contributions in a wide range of disciplines. However, one pervading theme can be identified in all of his work: the belief that mathematics, and in particular abstract algebra, was the language and key to uncovering the structure in many real world problems. One testament to this vision is his seminal habilitation thesis on the theory of Fourier transform algorithms, which ingeniously connects one of the principal tools in signal processing with group theory to open up an entirely new field of research. The authors deeply regret that Beth’s untimely death prevented him from seeing the Algebraic Signal Processing Theory, a body of work, including the present paper, that develops an axiomatic approach to and generalization of signal processing based on the representation theory of algebras. The theory is a logical continuation of Beth’s ideas and would not exist without him and his influence as PhD advisor. The authors like to think that he would have approved of this work and wish to dedicate this paper to him and his memory.
This work was supported by NSF through awards 0310941 and 0634967.  相似文献   

6.
S. H. Guo 《Acta Mechanica》2011,222(3-4):199-208
The motion equations of anisotropic media, coupled to the heat conduction equations, are studied here based on the L-S model and the G-L model. The complete set of uncoupled elastic and heat wave equations for anisotropic media are deduced. The results show that the L-S model is suitable for elastic materials and the G-L model is more suitable for dissipative materials. Based on these laws, we discuss the propagation behaviors of heat wave and elastic waves for isotropic media.  相似文献   

7.
H. M. Ma  X. -L. Gao 《Acta Mechanica》2010,211(1-2):115-129
The Eshelby tensor for a plane strain inclusion of arbitrary cross-sectional shape is first presented in a general form, which has 15 independent non-zero components (as opposed to 36 such components for a three-dimensional inclusion of arbitrary shape). It is based on a simplified strain gradient elasticity theory that involves one material length scale parameter. The Eshelby tensor for an infinitely long cylindrical inclusion is then derived using the general form, with its components obtained in explicit (closed-form) expressions for the two regions inside and outside the inclusion for the first time based on a higher-order elasticity theory. This Eshelby tensor is separated into a classical part and a gradient part. The latter depends on the position, the inclusion size, the length scale parameter, and Poisson’s ratio. As a result, the new Eshelby tensor is non-uniform even inside the cylindrical inclusion and captures the size effect. When the strain gradient effect is not considered, the gradient part vanishes and the newly obtained Eshelby tensor reduces to its counterpart based on classical elasticity. The numerical results quantitatively show that the components of the new Eshelby tensor vary with the position, the inclusion size, and the material length scale parameter, unlike their classical elasticity-based counterparts. When the inclusion radius is comparable to the material length scale parameter, it is found that the gradient part is too large to be ignored. In view of the need for homogenization analyses of fiber-reinforced composites, the volume average of the newly derived Eshelby tensor over the cylindrical inclusion is obtained in a closed form. The components of the average Eshelby tensor are observed to depend on the inclusion size: the smaller the inclusion radius, the smaller the components. However, as the inclusion size becomes sufficiently large, these components are seen to approach from below the values of their classical elasticity-based counterparts.  相似文献   

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Scientometrics - We use some modern scientometrics tools to detect which articles written in co-authorship are the most influential in the finance theory literature from 1896 to 2006. To develop a...  相似文献   

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A topological analysis of different rf SQUID structures is performed. A simple unified picture of these devices is obtained by considering the topological properties of the magnetic force lines around superconducting (or resistive) SQUID structures containing one weak link. Due to the periodic collapse of the superconducting order parameter in the weak link the normal space around these structures can change its connectivity. A number of rf SQUID structures are analyzed from the point of view of simple topological homotopy theory. The rf SQUID is then viewed as a device which realize a topological switching between two different classes of simple closed loops of the magnetic force lines. This switching (through the weak superconductivity region) is modulated by the low-frequency closed loops of the magnetic field and results in the well-known periodic response of the rf SQUID. The surfaces surrounding the rf excitation coil of the rf SQUID are analyzed from the point of view of homology theory. The screening currents flowing on these surfaces are represented as one-dimensional closed loops (cycles). It is shown that the SQUID can work only if the surface of the structure has at least one class of so-called nonbounding cycles, which are all cut by the weak link. A number of known SQUID structures are analyzed from the point of view of homotopy and homology theory and some new SQUID structures are discussed.  相似文献   

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Free vibration analysis of simply supported functionally graded plates (FGP) resting on a Winkler–Pasternak elastic foundation are examined by a new higher shear deformation theory in this paper. Present theory exactly satisfies stress boundary conditions on the top and the bottom of the plate. The material properties change continuously through the thickness of the plate, which can vary according to power law, exponentially or any other formulations in this direction. The equation of motion for FG rectangular plates resting on elastic foundation is obtained through Hamilton’s principle. The closed form solutions are obtained by using Navier technique, and then fundamental frequencies are found by solving the results of eigenvalue problems. The numerical results obtained through the present analysis for free vibration of functionally graded plates on elastic foundation are presented, and compared with the ones available in the literature.  相似文献   

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The available plate theories either have not considered the interlaminar stress continuity condition or have been calibrated based on linear strain–displacement relations. Moreover, almost all buckling analyses performed so far employing the global–local plate theories, were restricted to linear, static buckling analyses of the perfect plates, neglecting the transverse normal strain and stress. Researches available in literature for dynamic buckling analyses of the sandwich plates are very rare. In the present paper, a generalized high-order global–local theory that satisfies all the kinematic and transverse stress continuity conditions at the interfaces of the layers, is proposed to investigate dynamic buckling of imperfect sandwich plates subjected to thermo-mechanical loads. In comparison to the layerwise, mixed, and available global–local theories, the present theory has the advantages of: (1) less required computational time due to using the global–local technique and matrix formulations, (2) higher accuracy due to satisfying the complete interlaminar kinematic and transverse stress continuity conditions and considering the transverse flexibility, (3) suitability for non-linear analyses, (4) capability of investigating the local phenomena, such as the wrinkling. To enhance the accuracy of the results, compatible Hermitian quadrilateral elements are employed. The buckling loads are determined based on a criterion previously published by the author.  相似文献   

13.
The classical Neumann–Kelvin (NK) linear potential flow model of 3D flow about a ship hull steadily advancing in calm water is reconsidered, and a modified theory—called Neumann–Michell (NM) theory—is given. The main difference between the two theories is that the line integral around the ship waterline that occurs in the classical NK boundary-integral flow representation is eliminated in the NM theory. Specifically, the integrand of the waterline integral in the NK theory is ${G\phi_x-\phi G_x}$ , where x is the coordinate along the ship length, ${\phi}$ is the flow potential, and G is the Green function associated with the Kelvin–Michell linear free-surface boundary condition. It is shown that the term ${G \phi_x}$ does not appear in a consistent linear flow model. Furthermore, the term ${\phi G_x}$ can be eliminated using a mathematical transformation, which amounts to an integration by parts.  相似文献   

14.
We have formulated the fundamentals of the hydrodynamic theory of the “Struya” former-flowmeter — a device for measuring the fluid flow rate and forming a homogeneous flow and a representative sample for subsequent qualitative analysis of the fluid medium composition. On the basis of the numerical solution of the Navier–Stokes equations, computer simulation of the flow of a viscous medium in the “Struya” former has been carried out. Models of homogeneous flow of a single incompressible fluid and of inhomogeneous flow of a two-phase dispersive fluid have been considered. Numerical calculations have confirmed the high characteristics of the “Struya” former which, as compared to the standard restrictions, has the lowest level of hydraulic losses and the highest accuracy of differential pressure formation. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 82, No. 2, pp. 308–319, March–April, 2009.  相似文献   

15.
Hao Wu  Bo Li  Yijian Pei  Jun He 《Scientometrics》2014,101(3):1955-1972
The name ambiguity problem presents many challenges for scholar finding, citation analysis and other related research fields. To attack this issue, various disambiguation methods combined with separate disambiguation features have been put forward. In this paper, we offer an unsupervised Dempster–Shafer theory (DST) based hierarchical agglomerative clustering algorithm for author disambiguation tasks. Distinct from existing methods, we exploit the DST in combination with Shannon’s entropy to fuse various disambiguation features and come up with a more reliable candidate pair of clusters for amalgamation in each iteration of clustering. Also, some solutions to determine the convergence condition of the clustering process are proposed. Depending on experiments, our method outperforms three unsupervised models, and achieves comparable performances to a supervised model, while does not prescribe any hand-labelled training data.  相似文献   

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International Journal of Mechanics and Materials in Design - A generalized non-local stress–strain gradient theory is presented using fractional calculus. The proposed theory includes as a...  相似文献   

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ABSTRACT

Case studies offer an opportunity to review what worked and what didn't and to draw conclusions about what changes to make in future projects. This article presents two different studies. Each study explored the properties of a production process and each had a number of issues to be resolved before experimental runs could be performed. In the first case, the process was a continuous rubber extrusion line, producing windscreen wiper blades. Planning involved people on three different continents, so issues of building trust were paramount. Only a narrow time window was available for experimentation, so flexibility and a quick response to problems as they arose were needed. The second study was an off-line batch process aimed at producing polymers suitable for artificial corneas. There were two competing variables of interest. Previous attempts to improve the product had been piecemeal and unsuccessful, but a fractional factorial experiment provided guidance on a way forward. Subsequent runs then aimed to optimize the primary variable whilst holding the second variable constant. By comparing and contrasting these studies, many valuable lessons can be learned.  相似文献   

18.
This paper focuses on a special segment of motorcyclists in Taiwan – riders of heavy motorcycles – and investigates their speeding behavior and its affecting factors. It extends the theory of planned behavior (TPB) to explore motorcyclist speeding behavior by including the variables of psychological flow theory. The levels of sensation-seeking and riding experience are also used as grouping variables to investigate group differences from the influences of their affecting factors on speeding behavior. The results reveal that the psychological flow variables have greater predictive power in explaining speeding behavior than the TPB variables, providing useful insights into the unique nature of this group of motorcyclists, who are more prone to engage in speeding. Group differences with regard to both sensation-seeking and rider experience in speeding behavior are highlighted, and the implications of the findings are discussed.  相似文献   

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A model of condensation-decay rate constants that are linear with respect to the number of monomers in the nucleus is considered. In a particular case of stable growth, this model leads to an exact solution of discrete kinetic equations of the theory of heterogeneous nucleation in the form of the Pólya distribution function. An asymptotic solution in the region of large nucleus sizes that satisfies the normalization condition and provides correct mean nucleus size has been found. It is shown that, in terms of the logarithmic invariant size, the obtained distribution has a universal time-independent form. The obtained solution, being more general than the double-exponent distribution used previously, describes both Gaussian and asymmetric distributions depending on the rate constant of condensation on a bare core. The obtained results are useful for modeling processes in some systems, in particular, the growth of linear chains, two-dimensional clusters, and filamentary nanocrystals.  相似文献   

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