Effective Simulations of Electronic Transport in 2D Structures Based on Semiconductor Superlattice Infinite Model

Effective simulations of semiconductor superlattices are presented in the paper. The simulations have been based on the Wannier function method approach where a new algorithm, inspired by Büttiker probes, has been incorporated into determining the Green function procedure. The program is of a modular structure, and its modules can either work independently, or interact with each other following a predefined algorithm. Such structuring not only accelerates simulations and makes the transport parameters possible to initially assess, but also enables accurate analysis of quantum phenomena occurring in semiconductor superlattices. In this paper, the capabilities of type I superlattice simulator, developed earlier, are presented, with particular emphasis on the new block where the Fermi levels are determined by applying Büttiker probes. The algorithms and methods used in the program are briefly described in the further chapters of our work, where we also provide graphics illustrating the results obtained for the simulated structures known from the literature.

Categoricity and the natural numbers

This chapter focuses on modelists who want to pin down the isomorphism type of the natural numbers. This aim immediately runs into two technical barriers: the Compactness Theorem and the Löwenheim-Skolem Theorem (the latter is proven in the appendix to this chapter). These results show that no first-order theory with an infinite model can be categorical; all such theories have non-standard models. Other logics, such as second-order logic with its full semantics, are not so expressively limited. Indeed, Dedekind's Categoricity Theorem tells us that all full models of the Peano axioms are isomorphic. However, it is a subtle philosophical question, whether one is entitled to invoke the full semantics for second-order logic — there are at least four distinct attitudes which one can adopt to these categoricity result — but moderate modelists are unable to invoke the full semantics, or indeed any other logic with a categorical theory of arithmetic.

An Infinite Model Predictive Controller for Multi Input Nonlinear Processes

This paper presents a novel algorithm of an infinite model predictive controller for controlling nonlinear multi-input multi-output (MIMO) processes. The new strategy uses a set of continuous nonlinear functions that captures the nonlinear characteristics of the MIMO plant over a wide operating range resulting in a more accurate prediction of the controlled variables. The method formulates a nonlinear dynamic matrix that is manipulated variable dependent during closed-loop control. The proposed algorithm was implemented on a nonlinear MIMO thermal system comprising of three temperature zones to be controlled with interacting effects. The experimental closed-loop responses of the proposed algorithm were compared to a multi-model dynamic matrix controller (DMC) with improved results for various setpoint trajectories. The MIMO process has nonlinear parameters such as process gain and time constant that are dependent on the size of the control actions. Good disturbance rejection was attained resulting in improved tracking of multi-setpoint profiles in comparison to multi-model DMC.

Analysis of finite-source cluster networks

Nowadays the distributed heterogeneous resources of networks, like the computational grid, start to have a greater part of interest so, the investigations of such systems are vital. Because of the more efficient utilisation of the resources, the job scheduling becomes more challenging for the system administrators. The allocation of the arriving jobs has a great impact on the efficiency and the energy consumption of the system. In this paper, we present a finite source generalized model for the performance evaluation of scheduling compute-intensive jobs based on the infinite model of Tien Van Do. The available computers are classified into three groups. This classification is based on two aspects: high performance priority (HP) and energy efficiency priority (EE). We investigate three schemes (separate queue, class queue and common queue) for buffering the jobs in a computational cluster that is built from Commercial Off-The-Shelf (COTS) servers. Our main interest is to calculate performance measures and energy consumption of the system using the different buffering schemes and classifications.

Empirical Analysis of Operational Efficiency of China’s Telecommunication Industry: Based on DEA Approach

By combining the Data Envelopment Analysis (DEA) method, from the view of time and district, this paper carries out a dynamic evaluation of resource allocation efficiency of China’s telecommunication industry from 1973 to 2008. The results show that technical efficiency indicator and technological progress indicator are the major factors of resources allocation of China’s telecommunication industry. It analyzed and studied all previous reorganization and regulation effects to the telecom with the reference to the efficiency changes of the telecom industry. Based on the non-Archimedean infinite model C2R of the Data Envelopment Analysis, combined with characteristics of inputs and outputs of China’s telecommunication industry, the paper sets up an indicator system of inputs and outputs as well as an overall efficiency evaluation model China’s telecommunication industry.