On the nature of kink MHD waves in magnetic flux tubes

Magnetohydrodynamic (MHD) waves are often reported in the solar atmosphere and usually classified as slow, fast, or Alfv\'en. The possibility that these waves have mixed properties is often ignored. The goal of this work is to study and determine the nature of MHD kink waves. This is done by calculating the frequency, the damping rate and the eigenfunctions of MHD kink waves for three widely different MHD waves cases: a compressible pressure-less plasma, an incompressible plasma and a compressible plasma with non-zero plasma pressure which allows for MHD radiation. In all three cases the frequency and the damping rate are for practical purposes the same as they differ at most by terms proportional to $(k_z R)^2$. In the magnetic flux tube the kink waves are in all three cases, to a high degree of accuracy incompressible waves with negligible pressure perturbations and with mainly horizontal motions. The main restoring force of kink waves in the magnetised flux tube is the magnetic tension force. The total pressure gradient force cannot be neglected except when the frequency of the kink wave is equal or slightly differs from the local Alfv\'{e}n frequency, i.e. in the resonant layer. Kink waves are very robust and do not care about the details of the MHD wave environment. The adjective fast is not the correct adjective to characterise kink waves. If an adjective is to be used it should be Alfv\'{e}nic. However, it is better to realize that kink waves have mixed properties and cannot be put in one single box

Competitive balance in european football: comparison by adapting measures: national measure of seasonal imbalance and Top 3

1. Concept of competitive balance 2. Measures of competitive balance 3. Data, used measures and results 4. Conclusions

Belgian federalism after the sixth state reform

This paper highlights the most important institutional evolutions of Belgian federalism stemming from the implementation of the sixth state reform (2012-2014). This reform inter alia included a transfer of powers worth 20 billion euros from the federal level to the level of the federated states, a profound reform of the Senate, and a substantial increase in fiscal autonomy for the regions. This contribution critically analyses the current state of Belgian federalism. Although the sixth state reform realized important and long-awaited changes, further evolutions are to be expected. Since the Belgian state model has reached its limits with regard to complexity and creativity, politicians and academics should begin to reflect on the seventh state reform with the aim of increasing the transparency of the current Belgian institutional labyrint

Breaks, cuts, and patterns

Wegeneralize the concept of a break by considering pairs of arbitrary rounds.Weshow that a set of homeaway patterns minimizing the number of generalized breaks cannot be found in polynomial time, unless P = NP. When all teams have the same break set, the decision version becomes easy; optimizing remains NP-hard.status: publishe

2-D direction of arrival estimation combining UCA-RARE and MUSIC for uniform circular arrays subject to mutual coupling

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Multiprocessor Global Scheduling on Frame-Based DVFS Systems

In this ongoing work, we are interested in multiprocessor energy efficient systems, where task durations are not known in advance, but are know stochastically. More precisely, we consider global scheduling algorithms for frame-based multiprocessor stochastic DVFS (Dynamic Voltage and Frequency Scaling) systems. Moreover, we consider processors with a discrete set of available frequencies

Quasar: A Programming Framework for Rapid Prototyping

We present a new programming framework, Quasar, which facilitates GPU programming. Our high-level programming language relieves the developer of all implementation details such that he can focus on the algorithm and the required accuracy. The proposed programming framework consists of a simple high-level programming language, an advanced compiler system, a runtime system and IDE. The Quasar language is a high level scripting language with an easy to learn syntax similar to python and MATLAB. This makes Quasar well suited for fast development and prototyping. A Quasar program is first processed by a front-end compiler that automatically detects serial and parallel loops that could be accelerated by heterogeneous hardware. In a second compilation phase, a number of back-end compilers processes the output of the front-end compiler, thus generating C++, OpenCL or CUDA code. Based on the generated code the runtime system can dynamically switch between CPU and GPU. This automatic scheduling at runtime is done by analyzing the load of all devices, the memory transfer cost and the complexity of the task. This way, the programmer is relieved from complicated implementation issues that are common for programming heterogeneous hardware. We validated the use of Quasar on a number of complex image processing and computer vision algorithms. These programs range from denoising to automated image segmentation applications. Using Quasar we get speed-up factors of 4 to over 60, depending on the application. All results were achieved using an NVIDIA GeForce M750

Soccer schedules in Europe: an overview

In this paper, we give an overview of the competition formats and the schedules used in 25 European soccer competitions for the season 2008-2009. We discuss how competitions decide the league champion, qualification for European tournaments, and relegation. Following Griggs and Rosa (Bull. ICA 18:65-68, 1996), we examine the popularity of the so-called canonical schedule. We investigate the presence of a number of properties related to successive home or successive away matches (breaks) and of symmetry between the various parts of the competition. We introduce the concept of ranking-balancedness, which is particularly useful to decide whether a fair ranking can be made. We also determine how the schedules manage the carry-over effect. We conclude by observing that there is quite some diversity in European soccer schedules, and that current schedules leave room for further optimizing