Kinematics of four-wheel-steering vehicles

In this paper, we review some aspects of the kinematical theory of four-wheel-steering (4WS) vehicles and present some new results and conclusions that we came across during our research on the subject. In a first paragraph, we compare the turning radius of two-wheel-steering (2WS) and 4WS vehicles and draw some interesting conclusions on the manoeuvring ability of either of them. In a second paragraph, we present a general kinematical analysis of 4WS vehicles by considering either the simplified two-wheel (bicycle) model or the more complete four-wheel model. In this analysis, we assume the sideslip angles of the wheels as non-negligible and we derive the general formulae relating the steering angles of the wheels to the geometrical data of the vehicle. By taking as zero the steering angles of the rear wheels, we derive from the above relations the well-known formulae of Ackermann–Jeantaux that are valid for 2WS vehicles.     

Parallel Krylov methods and the application to 3-d simulations of a triphasic porous media model in soil mechanics

We introduce a general parallel model for solving coupled nonlinear and time-dependent problems in soil mechanics, where we employ general purpose linear solvers with specially adjusted preconditioners. In particular, we present a parallel realization of the GMRES method applied to a triphasic porous media model in soil mechanics, where we compute the deformation of unsaturated soil together with the pore-fluid flow of water and air in the soil. Therefore, we propose a pointwise preconditioner coupling all unknowns at the nodal points. In two large-scale numerical experiments we finally present an extended evaluation of our parallel model for demanding configurations of the triphasic model.     

Gröbner bases and combinatorics for binary codes

In this paper we introduce a binomial ideal derived from a binary linear code. We present some applications of a Gröbner basis of this ideal with respect to a total degree ordering. In the first application we give a decoding method for the code. In the second one, by associating the code with the set of cycles in a graph, we can solve the problem of finding all codewords of minimal length (minimal cycles in a graph), and show how to find a minimal cycle basis. Finally we discuss some results on the computation of the Gröbner basis.     

Ballistic Transport in Classical and Quantum Integrable Systems

In this essay, we first sketch the development of ideas on the extraordinary dynamics of integrable classical nonlinear and quantum many body Hamiltonians. In particular, we comment on the state of mathematical techniques available for analyzing their thermodynamic and dynamic properties.Then, we discuss the unconventional finite temperature transport of integrable systems using as example the classical Toda chain and the toy model of a quantum particle interacting with a fermionic bath in one dimension; we focus on the singular long time asymptotic of current-current correlations, we introduce the notion of the Drude weight and we emphasize the role played by conservation laws in establishing the ballistic character of transport in these systems.     

An original approach to eddy current problems through a complexelectrical image concept

In this paper, we propose an original method for the physical analysis of electromagnetic interactions between an inductive sensor and any homogeneous conducting plane target. In the first part of this paper, the basic principles of inductive sensors are recalled. Then, we solve Maxwell's equations in order to obtain an analytical model for the relationship between the target properties and the electrical signals for a U-shaped sensor. Next, we emphasize the fact that our analytical relations can be interpreted as an extension of the electrical image method, even in the most difficult case of conducting and magnetic targets. In the last part, we present some measurements illustrating this new electrical image concept     

A generative model of article citation networks of a subject from a large-scale citation database

Scientometrics - In this paper, we analyze the structure of the article citation network of a particular subject obtained from the Web of Science (WoS) database. In specific, we modify a model...     

Integrated planning in supply chains with buy-side and sell-side marketplaces

In this paper we develop a quadratic programming model for partner selection and planning in integrated supply chain networks embedded with both sell-side and buy-side electronic marketplaces. Such a scenario arises in several practical applications. In particular, we consider a contract manufacturer who procures components from suppliers through a component marketplace and sells its manufactured sub-assemblies to original equipment manufacturers (OEMs), through a sub-assembly marketplace. In these web-enabled supply chains, embedded with upstream and downstream electronic marketplaces, we need methods for online supply-chain partner selection based on pricing and delivery schedules. In this paper, we develop and present such a model that selects partners, synchronizes supply chain activities and optimizes the profit through optimal revenue pricing and cost minimization.     

设计集成管理系统

考察了管理方法的演变并建议进行集成管理系统垢研究和设计。第一部分讨论了各种管理方法的繁衍并强调了将行之有效的方法组合在一起以适应特殊环境的重要生。第二部分介绍了一种用以研究管理方法的组织原则：管理的机械模型通过生物醛以社会模型的演变。还描绘了弈和复杂性的压力,这些压力推动和支持管理模型的演变。部分他全面质量管理（ＴＱＭ）是迄今为止支持组织从机械和生物模型转变为社会模型的最全面的系统,尽管它出有不足     

设计集成管理系统（Ⅱ）

考察了管理方法的演变并建议进行集成管理系统的研究和设计。第一部分讨论了各种管理方法的繁衍并强调了将行之有效的方法组合在一起以适应特殊环境的重要性。第二部分介绍了一种用以研究管理方法的组织原则：管理的机械模型通过生物模型到社会模型的演变。还描绘了一些变革和复杂性的压力这些压力推动和支持管理模型的演变。第三部分讨论了全面质量管理（ＴＱＭ）是迄今为止支持组织从机械和生物模型转变为社会模型的最全面的系统,     

Physical properties of a trapped two-level ion decaying by thermal and squeezed vacuum reservoirs

In this paper, we first study the interaction between a trapped two-level ion with a field reservoir in a general form. Then, we use thermal and squeezed vacuum reservoirs to continue our investigation. We try to find the equation of motion for the whole system density operator by applying the Weisskopf theory. Next, we evaluate the explicit form of the density matrix elements analytically. In the obtained density matrix elements, we arrive at some physical parameters of the trapped ion system as well as the applied field reservoirs by which one can control the transition probabilities between the trapped ionic states. We also introduce some hermitian operators for the trapped ion system and calculate the expectation values of their time evolution by considering the mentioned two reservoirs. In the continuation, we design a system for measuring the hermitian trapped ion’s operators theoretically. Finally, we find a way to transport the information of the trapped ion system by our proposed quantum processor.     

Efficient evaluation of three-phase coexistence lines

The Gibbs-Duhem integration method is a means for evaluating phase diagrams by molecular simulation. Starting from a state of known phase coexistence, one applies the Clapeyron equation to trace out subsequent points on the saturation line. Each simulation yields a coexistence state, and particle exchanges are not invoked to insure equality of fugacities. We describe and demonstrate here the extension of this method to three-phase coexistence, namely, among a solid, a liquid, and a gas. In one application, we compute the saturation pressure and temperature as a function of composition (more accurately, as a function of fugacity fraction) for six Lennard-Jones two-component mixtures. In a second study, we traverse a mutation pathway; that is, we evaluate three-phase equilibriaas a function of the intermolecular potential. In particular, we define a path that transforms the Lennard-Jones model into a square well, and thus in our calculations we quantify the effect of the shape of the repulsive and attractive portions of the potential on the triple point. In the end we have what is, to our knowledge, the First estimate of a state of solid-fluid coexistence for a square well model. In both applications we assume that the fee crystal structure represents the thermodynamically stable solid phase.Paper presented at the Twelfth Symposium on Thermophysical Properties, June 19–24, 1994, Boulder, Colorado, U.S.A.     

Modelling hierarchical structure in functional brain networks

In this work, we focus on a complex-network approach for the study of the brain. In particular, we consider functional brain networks, where the vertices represent different anatomical regions and the links their functional connectivity. First, we build these networks using data obtained with functional magnetic resonance imaging. Then, we analyse the main characteristics of these complex networks, including degree distribution, the presence of modules and hierarchical structure. Finally, we present a network model with dynamical nodes and adaptive links. We show that the model allows for the emergence of complex networks with characteristics similar to those observed in functional brain networks.     

Do men and women differ in their use of tables and graphs in academic publications?

In psychological research there is huge literature on differences between the sexes. Typically it used to be thought that women were more verbally and men more spatially oriented. These differences now seem to be waning. In this article we present three studies on sex differences in the use of tables and graphs in academic articles. These studies are based on data mining from approximately 2,000 articles published in over 200 peer-reviewed journals in the sciences and social sciences. In Study 1 we found that, in the sciences, men used 26 % more graphs and figures than women, but that there were no significant differences between them in their use of tables. In Study 2 we found no significant differences between men and women in their use of graphs and figures or tables in social science articles. In Study 3 we found no significant differences between men and women in their use of what we termed ‘data’ and ‘text’ tables in social science articles. It is possible that these findings indicate that academic writing is now becoming a genre that is equally undertaken by men and women.     

Modelling and optimization of the assembly process in a flexible cell for aircraft panel manufacturing

In this paper we consider a manufacturing problem arising in a robotic cell for aircraft panels assembly. An initial technological analysis has shown that some mechanical assembly phases, which involve a huge amount of riveting and screwing operations, can be automated. The motivation of this research is to find the most profitable sequencing of the operations from the viewpoint of throughput time. In particular, we focus on the set-up activities related to switching between operations. The problem is to find the permutation of operations such that the overall switching time is a minimum. In the situation on hand, major precedence constraints among the operations hold. The problem is formulated as an instance of the well-known 'sequential ordering problem', for which we propose a tabu search solution heuristic. In this paper we report on both the modelling process and the solution procedures.     

Topological rigidity of semigroups of affine maps

We study the topological rigidity of affine semigroups of algebraic actions. In the first part of the paper we given an algebraic condition for rigidity that unifies previous rigidity results and we settle an old question of Walters. In the second part we study a generalized notion of the rigidity of hyperbolic actions.     

A comparison of overall and sub-area journal influence: The case of the accounting literature

In most scientific disciplines, a number of divergent and often highly specialized research areas are examined, which is reflected in substantial differences among journal scopes. Using the accounting literature as an example, we argue that this diversity in scopes should be considered when assessing journal influence. Concretely, we examine a citation-based structural influence measure for a sample of 41 accounting journals. Next, we identify sub-areas in the accounting literature and we explore journal influence in these sub-areas. Our results clearly demonstrate the importance of distinguishing between overall and sub-area influence. In addition, we show that sub-areas should be identified using a fuzzy clustering procedure.     

Interactive effects of seasonal-demand characteristics on manufacturing systems

In this paper, we identify different characteristics of seasonal demands and analyse their impact on manufacturing systems. In particular, we consider a single-stage production facility that has flexibility to adjust its production rates or inventory target levels. Using Markov decision process formulation, we analyse a model that minimises the total cost under infinite horizon discounted and average cost criteria. Through extensive numerical studies, we reveal several insights related to the individual and joint impact of seasonal demand characteristics that are of practical interests to manufacturers.     

Plasmon-enhanced solar water splitting with metal oxide nanostructures: A brief overview of recent trends

In the last decade, the surface plasmon resonance-enhanced solar water splitting (SWS) has been actively investigated for improved hydrogen production. In this mini-review, we briefly introduce the mechanisms for plasmon-enhanced SWS and then review some representative studies related to these mechanisms. In addition, we also briefly discuss how metal oxide geometry affects the SWS activity in combined metal-semiconductor nanostructures. Finally, we summarize the recent discoveries and proposed a future vision for plasmon-enhanced SWS with metal oxide nanostructures.     

Steady-state solution of Fokker-Planck equation in higher dimension

The purpose of the present paper is a contribution to the study of steady-state p.d.f. for mechanical systems of higher dimension, using the FKP equation method. The article contains three parts. In part I we recall results about Ito stochastic differential equations and FKP equation and we set the problem. In part II we present a result concerning an exact steady-state p.d.f. for a class of nonlinear dynamical systems of higher dimension. In part III we develop a numerical method to solve the FKP equation in a reasonable higher dimension. We present a numerical example in a 12 dimensions case.     

真空微电子管的研究

综合了已有的真空微电子器件理论的研究成果，提出了真空微电子三极管优化模型，并且进行了初步计算，得到了真空微电子三极管优化模型的理论特性。同时，利用独创的无版光刻工艺制作了真空微电子三极管，进行了测试，并且与理论结果进行了比较。