Fourier Analysis of Serial Dependence Measures

Classical spectral analysis is based on the discrete Fourier transform of the autocovariances. In this article we investigate the asymptotic properties of new frequency‐domain methods where the autocovariances in the spectral density are replaced by alternative dependence measures that can be estimated by U‐statistics. An interesting example is given by Kendall's τ, for which the limiting variance exhibits a surprising behavior.     

Das digitale geologische Strukturmodell Bitterfeld als neuer Baustein in der Sanierungsforschung

Identification, assessment and remediation of a large-scale groundwater contamination requires a profound knowledge of the geological structure to predict the fate of contaminants in the subsurface. Within the SAFIRA-project, a model sector of the Bitterfeld/Wolfen area was chosen to transfer the structural geological data of the Tertiary and Quarternary aquifer units into a digital geological model. Using 125 selected drillholes as a base of 28 networked cross-sections, small-scale lithological and structural heterogeneities, in particular of the Quarternary layers, could be assigned to 31 litho-stratigraphic sedimentation units and depicted using a 10 × 10 m GIS grid. An assignment of hydraulic parameters to individual sedimentary bodies allows a combination with flow and transport models. The structural model was generated by combining gridding sections and additional point and lateral information of sediment distribution and allows -beyond visualisation purposes- volumetric calculations of distinct sedimentary units, which are relevant for an assessment of retardation processes in the remaining lignite seam. The present structural model is the base for a “Spatial Model Bitterfeld” and anables further investigations on the environmental impact of different scenarios.     

Optical particle sizing in backscatter

Several possibilities for the use of elastic light scattering in the backscatter range (scattering angle theta(s) > 140 deg) for determination of size, velocity, and refractive index of spherical particles are investigated. First the phase Doppler technique is considered. Numerical simulations of light scattering with the Lorenz-Mie theory are used to show that the phase Doppler technique is unsuitable for such backscatter configurations, except for special measurement conditions. The time-shift (or pulse-displacement) technique is then considered by use of the Fourier-Lorenz-Mie theory. Simulations show that up to four fractional signals can be obtained by use of the technique in backscatter, corresponding to the scattering order or modes: surface wave (long path), reflection, second-order refraction (inner path), and a mixture of second-order refraction (outer path) and surface wave (short path). Signal characteristics as a function of particle size, refractive index, and particle ellipticity are studied. Suggestions for a practical measurement instrument are put forward.     

A survey of approaches for the visual model-driven development of next generation software-intensive systems

Software-intensive systems of the future are expected to be highly distributed and to exhibit adaptive and anticipatory behavior when operating in highly dynamic environments and interfacing with the physical world. Therefore, visual modeling techniques to address these software-intensive systems require a mix of models from a multitude of disciplines such as software engineering, control engineering, and business process engineering. As in this concert of techniques software provides the most flexible element, the integration of these different views can be expected to happen in the software. The software thus includes complex information processing capabilities as well as hard real-time coordination between distributed technical systems and computers.In this article, we identify a number of general requirements for the visual model-driven specification of next generation software-intensive systems. As business process engineering and software engineering are well integrated areas and in order to keep this survey focused, we restrict our attention here to approaches for the visual model-driven development of adaptable software-intensive systems where the integration of software engineering with control engineering concepts and safety issues are important. In this survey, we identify requirements and use them to classify and characterize a number of approaches that can be employed for the development of the considered class of software-intensive systems.     

SWOF - an open framework for shared workspaces to support different cooperation tasks

Computer supported collaborative work (CSCW) allows people to cooperate by computers from different places and at different times. To enable an easier integration of such collaborative components into web-based communities and portals, a Shared Workspace Open Framework (SWOF) was developed. This framework provides the basic features of shared workspaces and can be customized to different cooperation cases. High usability is an important aspect of the implementation. To achieve these aims SWOF focuses on an information space with more task-suited item-types that can help to pre-structure the information. Thus, on the one hand the system can help the users to write down the needed information in a consistent way and, on the other, could reduce the arguments between the group members on how to structure their workspace. As a use case for SWOF the development of a Web-based portal for the community of man-machine interaction was chosen. In the project MMI-Interaktiv, a portal is built with a SWOF-based shared workspace component. An evaluation for this use case is presented.     

Estimation of Quantum Channels with Finite Resources

We examine the problem of determining the parameters that describe a quantum channel. It is assumed that the users of the channel have at best only partial knowledge of it and make use of a finite amount of resources to estimate it. We discuss simple protocols for the estimation of the parameters of several classes of channels that are studied in the current literature. A quantitative measures of the quality of the estimation schemes can be given on the basis of the standard deviation or of the fidelity. Protocols that employ entangled particles are also discussed. The use of entangled particles as a nonclassical resource enhances the estimation quality of some classes of quantum channel. Further, the methods presented here can be extended to higher dimensional quantum systems. PACS: 03.67.Hk     

Heat transfer between gas fluidized beds of solid particles and the surfaces of immersed heat exchanger elements,part I

After some general remarks about fluidization, and a section on the hydrodynamic behaviour of fluidized beds, the mechanisms of heat transfer between the surfaces of heat exchanger elements and gas—solid fluidized beds are discussed in detail. A theoretical model, presented some years ago, is slightly modified and further developed to improve its applicability within a wide range of variables. The model makes use of some of the basic concepts of molecular kinetic theory as applied to solid particles in a fluidized bed. A complete derivation as well as all the parameters required to apply the model equations are given.     

Development of novel 1,2,3,4-tetrahydroisoquinoline derivatives and closely related compounds as potent and selective dopamine D3 receptor ligands

Based on N-alkylated 1,2,3,4-tetrahydroisoquinoline derivatives, which are structurally related to the partial agonist BP 897, a series of novel, selective dopamine D3 receptor antagonists has been synthesised. Derivatisation included changes in the arylamide moiety and the tetrahydroisoquinoline substructure leading to compounds with markedly improved selectivities and affinities in the low nanomolar concentration range. From the 55 structures presented here, (E)-3-(4-iodophenyl)-N-(4-(1,2,3,4-tetrahydroisoquinolin-2-yl)butyl)acrylamide (51) has high affinity (Ki(hD3)=12 nM) and a 123-fold preference for the D3 receptor relative to the D2 receptor subtype. Its pharmacological profile offers the prospect of a novel radioligand as a tool for various dopamine D3-receptor-related in vitro and in vivo investigations.     

Diffusion-related implications for langasite resonator operation

Oxygen and gallium diffusivities in langasite were experimentally determined by analysis of diffusion profiles of 18O and 71Ga tracers by SIMS analysis as functions of temperature and doping. Strontium-enhanced diffusivities and activation energies of approximately 1.2+/-0.2 eV confirm the predominant role of oxygen vacancies in controlling the electrical conductivity of langasite at elevated temperature and oxygen partial pressure. The potential impact of high levels of porosity and the use of an oxygen primary ion beam on the accuracy of some of the data is discussed. The gallium diffusivity, with activation energy of 3.13 eV, was found to be more than two orders of magnitude lower than that of oxygen. Surface exchange measurements enabled estimation of gallium loss at elevated temperatures and oxygen partial pressure; the level is not believed to be of major concern for resonator performance.