307 research outputs found

    Automated user documentation generation based on the Eclipse application model

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    An application's user documentation, also referred to as the user manual, is one of the core elements required in application distribution. While there exist many tools to aid an application's developer in creating and maintaining documentation on and for the code itself, there are no tools that complement code development with user documentation for modern graphical applications. Approaches like literate programming are not applicable to this scenario, as not a library, but a full application is to be documented to an end-user. Documentation generation on applications up to now was only partially feasible due to the gap between the code and its semantics. The new generation of Eclipse rich client platform developed applications is based on an application model, closing a broad semantic gap between code and visible interface. We use this application model to provide a semantic description for the contained elements. Combined with the internal relationships of the application model, these semantic descriptions are aggregated to well-structured user documentations that comply to the ISO/IEC 26514. This paper delivers a report on the Ecrit research project, where the potentials and limitations of user documentation generation based on the Eclipse application model were investigated.Comment: 9 pages, 9 figure

    Gradients in urban material composition: A new concept to map cities with spaceborne imaging spectroscopy data

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    To understand processes in urban environments, such as urban energy fluxes or surface temperature patterns, it is important to map urban surface materials. Airborne imaging spectroscopy data have been successfully used to identify urban surface materials mainly based on unmixing algorithms. Upcoming spaceborne Imaging Spectrometers (IS), such as the Environmental Mapping and Analysis Program (EnMAP), will reduce the time and cost-critical limitations of airborne systems for Earth Observation (EO). However, the spatial resolution of all operated and planned IS in space will not be higher than 20 to 30 m and, thus, the detection of pure Endmember (EM) candidates in urban areas, a requirement for spectral unmixing, is very limited. Gradient analysis could be an alternative method for retrieving urban surface material compositions in pixels from spaceborne IS. The gradient concept is well known in ecology to identify plant species assemblages formed by similar environmental conditions but has never been tested for urban materials. However, urban areas also contain neighbourhoods with similar physical, compositional and structural characteristics. Based on this assumption, this study investigated (1) whether cover fractions of surface materials change gradually in urban areas and (2) whether these gradients can be adequately mapped and interpreted using imaging spectroscopy data (e.g. EnMAP) with 30 m spatial resolution. Similarities of material compositions were analysed on the basis of 153 systematically distributed samples on a detailed surface material map using Detrended Correspondence Analysis (DCA). Determined gradient scores for the first two gradients were regressed against the corresponding mean reflectance of simulated EnMAP spectra using Partial Least Square regression models. Results show strong correlations with R2 = 0.85 and R2 = 0.71 and an RMSE of 0.24 and 0.21 for the first and second axis, respectively. The subsequent mapping of the first gradient reveals patterns that correspond to the transition from predominantly vegetation classes to the dominance of artificial materials. Patterns resulting from the second gradient are associated with surface material compositions that are related to finer structural differences in urban structures. The composite gradient map shows patterns of common surface material compositions that can be related to urban land use classes such as Urban Structure Types (UST). By linking the knowledge of typical material compositions with urban structures, gradient analysis seems to be a powerful tool to map characteristic material compositions in 30 m imaging spectroscopy data of urban areas

    Conductance and persistent current in quasi-one-dimensional systems with grain boundaries: Effects of the strongly reflecting and columnar grains

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    We study mesoscopic transport in the Q1D wires and rings made of a 2D conductor of width W and length L >> W. Our aim is to compare an impurity-free conductor with grain boundaries with a grain-free conductor with impurity disorder. A single grain boundary is modeled as a set of the 2D-δ\delta-function-like barriers positioned equidistantly on a straight line and disorder is emulated by a large number of such straight lines, intersecting the conductor with random orientation in random positions. The impurity disorder is modeled by the 2D δ\delta-barriers with the randomly chosen positions and signs. The electron transmission through the wires is calculated by the scattering-matrix method, and the Landauer conductance is obtained. We calculate the persistent current in the rings threaded by magnetic flux: We incorporate into the scattering-matrix method the flux-dependent cyclic boundary conditions and we introduce a trick allowing to study the persistent currents in rings of almost realistic size. We mainly focus on the numerical results for L much larger than the electron mean-free path, when the transport is diffusive. If the grain boundaries are weakly reflecting, the systems with grain boundaries show the same (mean) conductance and the same (typical) persistent current as the systems with impurities, and the results also agree with the single-particle theories treating disorder as a white-noise-like potential. If the grain boundaries are strongly reflecting, the typical persistent currents can be about three times larger than the results of the white-noise-based theory, thus resembling the experimental results of Jariwala et al. (PRL 2001). We extend our study to the 3D conductors with columnar grains. We find that the persistent current exceeds the white-noise-based result by another one order of magnitude, similarly as in the experiment of Chandrasekhar et al. (PRL 1991)

    The solution of dynamic response of hydraulic steel structures interacting with fluid

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    Predikce chování vodohospodářských konstrukcí se zřetelem na vlivy prostředí v různých návrhových stavech je základní podmínkou odhadu provozní spolehlivosti analyzované konstrukce. Podstatný význam má spolehlivá charakteristika chování konstrukce daná popisem jejího pohybu na časově proměnných vlivech prostředí. V současně používané formulaci inženýrské mechaniky jde o stanovení odezvy definované konstrukce nebo její části na zadané časově proměnné mechanické zatížení. Požadovanými odezvovými veličinami nutnými pro posouzení mezních stavů únosnosti a použitelnosti konstrukce jsou přemístění a napětí, resp. veličiny odtud odvozené. Základním prostředkem predikce odezvy konstrukce je výpočet. Předložená práce se zabývá komplexními multifyzikálními problémy chování vodohospodářských konstrukcí v interakci s kapalinou (fluid structure interaction). Popisují se různé přístupy k výpočtům statických i dynamických vlastností konstrukcí. Tyto přístupy jsou rozděleny na tzv. „přímou metodu“, která je založená na přímém spojení dvou fyzikálních polí a výpočet je proveden metodou konečných prvků a tzv. „nepřímou metodu“, která je založená na spojení dvou fyzikálních polí pomocí různých rozhraní, která jsou v této práci popsána. Při nepřímé metodě je výpočet proudící kapaliny proveden metodou konečných objemů a výpočet konstrukce metodou konečných prvků. V rámci disertační práce byly řešeny výše zmíněnými přístupy statické a dynamické odezvy vodohospodářských konstrukcí. Výsledky výpočtů v rámci předložené disertační práce byly srovnány s výsledky provedených experimentů. V závěru práce jsou popsány výsledky a zobecněné poznatky získané z řešených úloh různými přístupy. V příloze jsou uvedena makra APDL pro přenos tlakového zatížení z výpočtu proudění kapalin do výpočtu konstrukce.Behaviour prediction of hydraulic steel structures with the view to surrounding influences in various design dispositions is a fundamental condition for operational reliability assessment of the analyzed construction. Reliable characteristics of construction behaviour defined by the specification of its movement within changes caused by time and environmental influences is of great importance. In currently used engineering mechanics formulation it concerns setting the response of the defined construction or its part to the given time variable mechanic load. Required response values, which are necessary for evaluation terminal dispositions of capacity and usability of the construction, are trans-location and tension, or values thence derived. Calculation is basic means for response prediction of construction. The thesis presented deals with complex multi-physical behaviour problems of water supply constructions in fluid structure interaction. There are presented various approaches to calculations of static and dynamic qualities of constructions. These approaches are divided into so called “direct method”, which is based on direct connection between two physical fields and the calculation is performed by the method of final elements, and so called “indirect method” , which is based on connection of two physical fields by means of various interfaces, which are described in this thesis. In case of indirect method, the calculation of running liquid is performed by the method of final volumes and the construction calculation is performed by the method of final elements. Within the scope of this thesis, static and dynamic responses of water supply constructions have been solved with the use of the above mentioned approaches. The results of the calculations in the scope of this thesis have been compared with the findings of performed experiments. The final part of the thesis describes the results and generalized findings gathered from the tasks by various approaches.

    A Top-down and Bottom-up look at Emissions Abatement in Germany in response to the EU ETS

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    This paper uses top-down trend analysis and a bottom-up power sector model to define upper and lower boundaries on abatement in Germany in the first phase of the EU Emissions Trading Scheme (2005-2007). Long-term trend analysis reveals the decoupling of economic activity and carbon emissions in Germany that has occurred since 1996 and has accelerated since 2005, in response to rising commodities prices, the introduction of a carbon trading, and other measures undertaken in Germany. Differing emission intensity trends and emissions counterfactuals are constructed using emissions, power generation, and macroeconomic data. Resulting top-down estimates set the upper bound of abatement in Phase I at 121.9 mn tons for all EU-ETS sectors and 56.7 mn tons for the power sector only. Using the tuned version of the model “E-simulate” a lower boundary of Phase I abatement is established at 13.2 million tons, based only on fuel switching in the power sector, which constitutes 61% of German ETS sector emissions. The paper characterizes abatement, critically discusses the underlying assumptions of the outcomes, and examines the impact of two main factors on power sector abatement, namely price and load.Massachusetts Institute of Technology. Center for Energy and Environmental Policy Research

    Quantum and Boltzmann transport in the quasi-one-dimensional wire with rough edges

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    We study quantum transport in Q1D wires made of a 2D conductor of width W and length L>>W. Our aim is to compare an impurity-free wire with rough edges with a smooth wire with impurity disorder. We calculate the electron transmission through the wires by the scattering-matrix method, and we find the Landauer conductance for a large ensemble of disordered wires. We study the impurity-free wire whose edges have a roughness correlation length comparable with the Fermi wave length. The mean resistance and inverse mean conductance 1/ are evaluated in dependence on L. For L -> 0 we observe the quasi-ballistic dependence 1/ = = 1/N_c + \rho_{qb} L/W, where 1/N_c is the fundamental contact resistance and \rho_{qb} is the quasi-ballistic resistivity. As L increases, we observe crossover to the diffusive dependence 1/ = = 1/N^{eff}_c + \rho_{dif} L/W, where \rho_{dif} is the resistivity and 1/N^{eff}_c is the effective contact resistance corresponding to the N^{eff}_c open channels. We find the universal results \rho_{qb}/\rho_{dif} = 0.6N_c and N^{eff}_c = 6 for N_c >> 1. As L exceeds the localization length \xi, the resistance shows onset of localization while the conductance shows the diffusive dependence 1/ = 1/N^{eff}_c + \rho_{dif} L/W up to L = 2\xi and the localization for L > 2\xi only. On the contrary, for the impurity disorder we find a standard diffusive behavior, namely 1/ = = 1/N_c + \rho_{dif} L/W for L < \xi. We also derive the wire conductivity from the semiclassical Boltzmann equation, and we compare the semiclassical electron mean-free path with the mean free path obtained from the quantum resistivity \rho_{dif}. They coincide for the impurity disorder, however, for the edge roughness they strongly differ, i.e., the diffusive transport is not semiclassical. It becomes semiclassical for the edge roughness with large correlation length
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