Results of outdoor radon monitoring in Bratislava and Nováky

Measurements of radon activity concentration (RAC) were made in two localities of Slovakia. The first one is located on the campus of Comenius University in Bratislava, where radon has been monitored since 1991. The second area is situated in the city of Nováky (midwest Slovakia, ～150 km from Bratislava). The localities have a different orography. RAC was measured continuously by large-volume scintillation chambers. The outdoor air was sampled at a height of 1.5 m above the ground. Time courses of RAC in both localities have a similar character. The correlation coefficients between RAC in Bratislava and Nováky was quite high (R(2) = 0.45). However, RACs in Nováky were found out to be about two times higher (～12.1 Bq m(-3)) than in Bratislava.     

Map-based direct position control system for wireless ad-hoc networks

The mobility modelling is one of the most important issues in wireless ad-hoc networks, therefore our research activities are focused on this area. This paper presents a new solution for map-based mobility modelling system which enables direct position control for mobile stations. This system, based on the cooperation model between OPNET Modeler simulation environment and MATLAB tool, provides fully automated process of direct position control with respect to the initial requirement and attributes. Firstly, the input information are collected in OPNET Modeler and forwarded to MATLAB environment. After that, MATLAB process a map source stored as a bitmap image and runs the function which generates a set of coordinates. These coordinates are transferred back to OPNET Modeler and used for the direct movement control of mobile stations. Our system developed was evaluated by the set of simulation runs and the results are placed on the end of this paper.     

On some convergence results for FDM with irregular mesh

The proof of convergence of the finite difference method with arbitrary irregular meshes for some class of elliptic problems is presented. By the use of the truncation error technique and stability analysis it was showed that $\text{max}{}_{\mathrm{i}}\text{¦u}{}^{\mathrm{i}}\text{? u}{}_{\mathrm{h}}{}^{\mathrm{i}}\text{¦? Ch}$, i.e., the solution u_h converges linearly with the size of the star. Correctness of this theorem was also confirmed by numerical tests.     

ProPHLEX—An hp-adaptive finite element kernel for solving coupled systems of partial differential equations in computational mechanics

This paper presents an overview of the basic design and architecture of the ProPHLEX hp-adaptive finite element kernel. ProPHLEX was designed to be a commercial, robust implementation of hp-adaptivity driven by residual error estimation with the primary goal of being physics independent and computationally efficient on a wide array of computer hardware platforms. ProPHLEX can solve virtually any class of engineering problems which be may be mathematically formulated as a system of linear or nonlinear second-order partial differential equations and associated boundary conditions. It has been applied to compressible and incompressible fluid dynamics, linear and nonlinear solid mechanics, heat flow problems, as well as semiconductor device simulation. Examples of ProPHLEX customization for linear and nonlinear solid mechanics are presented.     

Implications of physical layer overhead on the design ofmultiaccess protocols

The authors examine the implications of physical layer overhead on the design of multiaccess protocols under a demand-assignment framework, comparing full-slot contention with mini-slot contention. Even if the physical layer overhead is substantial relative to the packet size, we show that after `paying the price' of transmitting the physical layer overhead it is still better, from a delay-throughput perspective, to only transmit a short request rather than a full packet during a contention period     

The sum of the parts does not equal the whole: Evidence from bihemispheric processing.

Examined in 5 experiments whether bihemispheric processing can be predicted from the processing observed when information is directed initially to just 1 hemisphere. Ss decided if laterally presented words rhymed with a previously presented central target. Trials varied in the degree to which the information displayed was redundant. On some trials, the same word appeared twice; in others, different words appeared, but they both led to the same decision; and finally, on some trials, different words appeared, each of which also led to a different decision. The patterns found for unilateral and bilateral trials were distinct. Furthermore, the pattern observed on bilateral trials could not be predicted from that found on unilateral trials, suggesting that interhemispheric interaction cannot be surmised from observing a hemisphere processing information in relative isolation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Probabilistic analysis of continuum damage mechanics of brittle materials

Uncertainty of material properties in solution of engineering problems is often a fundamental question. Statistical methods give a powerful tool for analysis of uncertainty. Monte Carlo simulations together with Gumbel distribution are used as a possible way to study influence of data dispersion on assessment of damage of brittle materials.     

An overview of lightwave packet networks

The unique systems opportunities offered by, and the unique systems constraints imposed by, lightwave technology as it applies to the field of distributed packet networks are examined. Single-channel and star topology approaches are first considered. Terabit-capacity lightwave networks are discussed, covering both wavelength-division and time-division multiplexing. Multichannel multihop lightwave networks are then considered, and a particular implementation, the ShuffleNet, is described, and its performance, as well as some simple addressing and routing schemes, is discussed     

Using a packet switch for circuit-switched traffic: a queueingsystem with periodic input traffic

Consideration is given to the effects of time-multiplexed stream traffic on the performance of a store-and-forward packet switch. Substantially reducing the amount of buffering in the switch results in only a small probability that an existing circuit will be disrupted during the length of its connection. For example, with a circuit-switched frame of length 1000 and 100% loading, reducing the buffer size from 999 packets to 83 results in only a 10^-6 circuit-disruption probability