This report deals with pilot-based channel estimation in wireless OFDM systems. We assume that the receiver is able to use all transmitted pilots, which is the case in broadcasting and in the downlink of a multiuser system. Four estimators (of which two have been proposed in the literature) are compared, both in terms of mean-squared error and bit-error rates. In the latter case, we simulate a mul

Syftet med denna studie har varit att söka ett systematiskt sätt att hantera problemsituationer under examensarbetshandledning. Ett teoretiskt ramverk har framställts med hjälp av litteratur om arbetspsykologi respektive handledning av doktorander. För att testa relevans och giltighet av ramverket genomfördes en intervju-undersökning om hantering av problematiska handlednings-situationer bland lär

We have tested the hypothesis that environmental factors can influence postischemic progenitor cell survival and differentiation in the dentate gyrus. The proliferation marker bromodeoxyuridine (BrdU) was administered during 7 days starting 24 h after ligation of the right middle cerebral artery. Postoperatively the rats were housed in standard cages or transferred to enriched environment 24 h or

The 70Ni nucleus has been produced at the LISOL facility and its beta decay to 70Cu has been observed. In parallel, the 70Cu nucleus has been produced at the ISOLDE facility. A new third beta-decaying isomeric state in 70Cu has been identified, partly with the aid of the in-source laser spectroscopy method. Its measured half-life is T1/2=33(2) s. In addition, two isomeric transitions in 70Cu have

The theory of nonequilibrium Green functions allows for a quantitative modeling of quantum cascade lasers. Explicit results are given for transport in a THz-laser and gain in a IR-Laser

In this paper we present some results on model based force estimationand how these estimates can be integrated in a common robot force controlscheme. A generalization of the force estimation method proposed inHacksel and Salcudean (1994) is done and a force observerable to follow ramp environmental forces is introduced. Anextension of this method for robotic manipulators is also experimentallyveri

The increasingly apparent environmental problems in our surroundings necessitate a quest for sustainable development in all areas of human endeavour. Within the field of chemistry and the production of chemicals, the focus is increasingly on the development of green chemistry. This discipline aims to reduce environmental impact by replacing petrochemical raw materials with renewable feedstock and

Metal sheet forming processes like deep drawing are applied in order to produce carriage parts in mass production. Therefore, forming tools are required that are well protected against wear. For such forming tools, wear resistant surfaces are, e.g., produced by thermal spraying of hard material coatings. The thermal spraying process itself is a highly transient thermo-mechanical process. In order