Eigenvalue problem for radial potentials in space with SU(2) fuzziness

The eigenvalue problem for radial potentials is considered in a space whose spatial coordinates satisfy the SU(2) Lie algebra. As the consequence, the space has a lattice nature and the maximum value of momentum is bounded from above. The model shows interesting features due to the bound, namely, a repulsive potential can develop bound-states, or an attractive region may be forbidden for particles to propagate with higher energies. The exact radial eigen-functions in momentum space are given by means of the associated Chebyshev functions. For the radial stepwise potentials the exact energy condition and the eigen-functions are presented. For a general radial potential it is shown that the discrete energy spectrum can be obtained in desired accuracy by means of given forms of continued fractions.Comment: 1+20 pages, 2 figs, LaTe

Modelling of krypton-xenon separation by dynamic fixed-bed adsorption on zeolite

International audienceCurrently noble gases are separated by cryogenic distillation, which is an expensive process with safety constraints due to the cryogenic temperatures used. Adsorptive separation, such as temperature/pressure swing adsorption, is studying as it is considered as an energy, safety and cost effective alternative. Different selective materials are described in the literature from inorganic adsorbents based on physical adsorption to new metal-organic frameworks (MOFs) based on size and chemistry. This work focuses on the description of a modelling of Kr-Xe separation by selective adsorption on a chabazite zeolite in a fixed bed column

From a Static Impossibility to an Adaptive Lower Bound: the Complexity of Early Deciding Set Agreement

In the year 2007 a reform was established that allowed private citizens in Sweden to make tax deductions on companies providing services pertaining to the household (called RUT-deduction). The year later another reform was introduced granting citizens additional tax deductions but this time concerning household renovation, reconstruction and extensive construction (called ROT-deduction). These tax deductions resulted in higher employment and more jobs being executed legally. The purpose of this paper is to examine and analyze what kind of effects these types of tax deductions would have on workers’ real wages and to look at to what extent these effects differ within a female dominated occupation and a male dominated occupation, from a gender perspective. The two professions that are chosen to be researched in this paper are the cleaning and painting professions. Furthermore, the purpose with this study is to examine whether this effect differs within the two separate professions. The study is executed with the use of econometric models, point estimation, economic theory and empirical studies. The result indicates that the RUT-deduction has the biggest positive impact on cleaners’ real wages. This paper shows that one underlying reason to this outcome could be that the cleaning service is a more price sensitive service and that the RUT-deduction might therefore have generated an excess in demand for that service. Nonetheless, to establish an equilibrium in the labor market the wages are required to rise in order to attract more cleaners to enter the certain market. However, this paper is unable to eliminate the possible theory of there being a general wage increase among workers in the private sector. In addition, this study is comprised of an inadequate amount of observations which impedes any reliable conclusions from being made based on evidence

The Driving Philosophers

We introduce a new synchronization problem in mobile ad-hoc systems: the Driving Philosophers. In this problem, an unbounded number of driving philosophers (processes) access a round-about (set of shared resources organized along a logical ring). The crux of the problem is to ensure, beside traditional mutual exclusion and starvation freedom at each particular resource, gridlock freedom (i.e., cyclic waiting chain amongst processes). The problem captures explicitly the very notion of process mobility and the underlying model does not involve any assumption on the total number of (participating) processes or the use of shared memory, i.e., the model conveys the ad-hoc environment. We present a generic algorithm that solves the problem in a synchronous model. Instances of this algorithm can be fair but not concurrent, or concurrent but not fair. We derive the impossibility of achieving fairness and concurrency at the same time as well as the impossibility of solving the problem in an asynchronous model. We also conjecture the impossibility of solving the problem in an ad-hoc network model with limited-range communication

A Topological Treatment of Early-Deciding Set-Agreement

This paper considers the k-set-agreement problem in a synchronous message passing distributed system where up to t processes can fail by crashing. We determine the number of communication rounds needed for all correct processes to reach a decision in a given run, as a function of k, the degree of coordination, and f <= t the number of processes that actually fail in the run. We prove a lower bound of min(\floor{f/k}+2,\floor{t/k}+1) rounds. Our proof uses simple topological tools to reason about runs of a full information set-agreement protocol. In particular, we introduce a new topological operator, which we call the early deciding operator, to capture rounds where k processes fail but correct processes see only k-1 failures

Tight Lower Bounds on Early Local Decisions in Uniform Consensus

The increased demand for renewable energy generation requires higher flexibility of transmission systems. This requirement together with technical progress in high-voltage direct-current (HVDC) technology have resulted in the ambition to build large-scale multi-terminal DC (MTDC) grids. To achieve this goal, vendor interoperability is considered a key element. Standards exist for AC systems,but not for DC systems. This work discusses and evaluates the suitability of AC standards for DC systems. As a result, a different view on substation architecture is developed and two communication protocols are suggested for further investigation in this context.QCR 20180314</p

The Driving Philosophers

We introduce a new synchronization problem in mobile ad-hoc systems: the Driving Philosophers. In this problem, an unbounded number of driving philosophers (processes) access a round-about (set of shared resources organized along a logical ring). The crux of the problem is to ensure, beside traditional mutual exclusion and starvation freedom at each particular resource, gridlock freedom (i.e., a cyclic waiting chain among processes). The problem captures explicitly the very notion of process mobility and the underlying model does not involve any assumption on the total number of (participating) processes or the use of shared memory, i.e., the model conveys the ad-hoc environment. We present a generic algorithm that solves the problem in a synchronous model. Instances of this algorithm can be fair but not concurrent, or concurrent but not fair. We derive the impossibility of achieving fairness and concurrency at the same time as well as the impossibility of solving the problem in an asynchronous model. We also conjecture the impossibility of solving the problem in an ad-hoc network model with limited-range communication