Performance of Reuse Partitioning in Cellular Systems with Mobile Users

Reuse partitioning (RP) is a simple technique that can be used to increase the traffic capacity in a cellular system. With RP, a cell is divided into several concentric regions, each associated with a different cluster size. In this article, a traffic model is developed to analyze the impact of mobile users on a two-region RP system using fixed channel assignment. The influence of user speed and cell size on the new call blocking probability, P_b, and the call dropping probability, P_d, is investigated. A simpler model that can be used to estimate P_b and P_d in some cases is described. The effect on system capacity of reserving some channels for handoff calls is also studied. It is found that even though prioritized handoff can reduce P_d, it may also degrade the capacity. The accuracy of the analysis is verified using simulation for three mobility models.     

A spherical aberration-corrected 200 kV TEM

A spherical aberration (Cs)-corrected 200 kV TEM was newly developed. The column of the microscope was extended by 25 cm and the inner yoke of the objective lens was modified to insert some parts of the corrector elements. The corrector has two hexapole elements that play a main role in Cs correction and they are placed at a position equivalent to the coma-free point of the objective lens by using two transfer doublet lenses. The Cs correction was successfully carried out by means of the third-order aberration that was generated in the two extended hexapoles. The Cs can be corrected to the desired value and also can be overcompensated in order to produce a negative Cs, as with the corrected Cs of -23 microm shown in this work. The optical system of the corrector does not produce second- and fourth-order aberrations, and can correct residual aberrations up to the third order. All of the corrector elements are computer-controlled and the third-order aberrations are quite stable after they are properly corrected. The resolution of 0.135 nm was experimentally confirmed by the Young's fringe method. Image simulations of a silicon [110] single crystal were made with various Cs and defocus values to demonstrate the effectiveness of arbitral control of Cs.     

Discerning nonstationarity from nonlinearity in seizure-free and preseizure EEG recordings from epilepsy patients

A number of recent studies indicate that nonlinear electroencephalogram (EEG) analyses allow to define a state predictive of an impending epileptic seizure. In this paper, we combine a method for detecting nonlinear determinism with a novel test for stationarity to characterize EEG recordings from both the seizure-free interval and the preseizure phase. We discuss differences between these periods, particularly an increased occurrence of stationary, nonlinear segments prior to seizures. These differences seem most prominent for recording sites within the seizure-generating area and for EEG segments less than one minute's length.     

Intel成功制作45nm芯片

Intel采用45nm工艺技术制作了该行业第一块全功能SRAM芯片,目标是于2007年采用该技术在300mm晶圆上开始制造芯片。目前Intel在Arizona和Oregon有两个制造厂制造65nm芯片,今年在Ireland和Oregon将有两个以上新厂投入生产。     

Method for FIR filters design with compressed cosine using Chebyshev's norm

This paper considers a new method for FIR filters design. The method uses an L_∞ optimality norm. To achieve a better approximating effect, a new modulating function which compresses the oscillations of the cosine is proposed. A parameter sets the gradient of the modulating function, with respect to the oscillations’ compression. The approximating polynomial is carried out using Remez’ exchange algorithm. An optimal polynomial with lowest possible (four) degree, that approximates an ideal filter's response with high precision is proposed. With the proposed method a FIR filter with arbitrary specifications can be designed. Design examples of FIR filters with a minimization of calculation are performed. The obtained filter's responses are close to the ideal response. The design examples demonstrate that the proposed approach may be a good alternative in several applications.     

New Acceleration Principle of Charged Particles for Electronic Applications. The General Hierarchic Description

A new principle of acceleration of changed particles and quasineutral plasma beams is proposed and theoretically substantiated. The essence of this new acceleration principle is die utilization of EH-undulated fields, which resemble those of EH free-electron laser pumping systems. Here the charged particles are moving in a superposition of crossed magnetic and electric vortex undulated fields (EH-accelerator). The advantage of such systems is that both negative (electrons) and positive (ions) charged particles are accelerated simultaneously in the same longitudinal direction. In addition to the concept of the EH-accelerators, a new theoretical approach (the theory of hierarchic oscillations and waves) is given further development here. This approach has been used as a basis for the general nonlinear theory of the EH-accelerators and some other similar isochronous electronic devices with long-time interactions. In addition, several new calculation methods are presented, including the method for nonlinear current density calculations (called the averaged current-density equation hierarchic method) and two versions of hierarchic asymptotic algorithms for the integration of Maxwell's equations.     

Environmental tax reform: an assessment of social responses in Ireland

Environmental tax reform (ETR) is widely accepted to be a policy with desirable environmental, and other economic effects. The question arises then as to why its implementation has been so patchy. There is a broad literature on the economic impact of ETR, however, there have been very few research efforts devoted to understanding the roles and imperatives of the public, policy makers, businesses and other stakeholders who are addressed by ETR. This paper examines the impediments to ETR in Ireland. Focus groups were formed comprising of members of the general public and these provided a forum for detailed reactions to the ETR concept. Interviews were conducted with policy makers and key business people in an attempt to identify both the patterns of thinking behind ETR and the main obstacles to its introduction. Having presented the results, a theory of the main impediments to ETR is developed. The opinions of the members of the public, the business community and the policy makers highlight a number of issues that need to be addressed in the future design of ETR in Ireland. The principal potential impediments to ETR include: mistrust of the government, implausibility of the policy, means of hypothecation, information asymmetries, the political system, the structure of government, the macroeconomic environment, the impact on competitiveness, inequity between sectors, regressivity, elasticities and the level of the tax, terminology, and the marketing of ETR.     

Can Markov regime-switching models improve power-price forecasts? Evidence from German daily power prices

Non-linear autoregressive Markov regime-switching models are intuitive. Time-series approaches for the modelling of electricity spot prices are frequently proposed. In this paper, such models are compared with an ordinary linear autoregressive model with regard to their forecast performances. The study is carried out using German daily spot-prices from the European Energy Exchange in Leipzig. Four non-linear models are used for the forecast study. The results of the study suggest that Markov regime-switching models provide better forecasts than linear models.     

A screen-printed interdigitated back contact cell using a boron-source diffusion barrier

A low-cost approach to fabricating interdigitated back contact cells is carried out on the principle of screen-printing a material that serves both to dope the rear surface and as a diffusion barrier to the dopant species of the opposite polarity. With this technique, an interdigitated pattern of n⁺ and p⁺ regions is formed on the cell back. Shunt-free rear interdigitated junctions are achieved. This work produced a cell with confirmed conversion efficiency of 10.5%. Areas for further efficiency gains are discussed.     

Observations of high temperature impinging-jet boiling phenomena

A high-speed video camera and microphone were used to capture the flow behavior and boiling sound of a free-surface water jet impinging on a high temperature surface during quench cooling. It was found that depending on the superheat of the surface considerably different flow patterns appeared. For cases where the initial surface temperature was above about 300 °C an almost explosive pattern appeared. This was in contrast to slightly lower temperatures where a liquid sheet flow structure was apparent. The change in phenomena was accompanied by a sudden change in the boiling sound and an increase in the heat transfer rate.