Evaluating walkability: a capability-wise planning and design support system     

Ivan Blečić  Arnaldo Cecchini  Tanja Congiu  Giovanna Fancello  Giuseppe A. Trunfio 《International journal of geographical information science》2013,27(8):1350-1374

We present a methodology and a planning and design support software tool for evaluating walkability and pedestrian accessibility of places which are relevant for people’s capabilities, and thus an important component of quality of life in cities. A multicriteria evaluation model, at the core of the decision support system, is used to assign walkability scores to points in urban space. Walkability scores are obtained through algorithms which process spatial data and run the evaluation model in order to derive potential pedestrian routes along the street network, taking into account the quality of urban space on several attributes relevant for walkability. One of its notable characteristics is a certain reversal of perspective in evaluating walkability: the walkability score of a place does not reflect how that place is per se walkable, but instead how and where to can one walk from there, that is to say, what is the walkability the place is endowed with. This evaluation incorporates three intertwined elements: the number of destinations/opportunities reachable by foot, their walking distances, and the quality of the paths to these destinations. In this article, we furthermore demonstrate possible uses of the support system by reporting and discussing the results of a case-study assessment of a project for the Lisbon’s Segunda Circular (Second Ring Road). The software tool is made freely available for download.  相似文献   

LMS‐based structural health monitoring of a non‐linear rocking structure     

J. Geoffrey Chase  Hannes A. Spieth  C. Francois Blome  J. B. Mander 《地震工程与结构动力学》2005,34(8):909-930

A structure's health or level of damage can be monitored by identifying changes in structural or modal parameters. This research directly identifies changes in structural stiffness due to modelling error or damage for a post‐tensioned pre‐cast reinforced concrete frame building with rocking beam column connections and added damping and stiffness (ADAS) elements. A structural health monitoring (SHM) method based on adaptive least mean squares (LMS) filtering theory is presented that identifies changes from a simple baseline model of the structure. This method is able to track changes in the stiffness matrix, identifying when the building is (1) rocking, (2) moving in a hybrid rocking–elastic regime, or (3) responding linearly. Results are compared for two different LMS‐based SHM methods using an L ₂ error norm metric. In addition, two baseline models of the structure, one using tangential stiffness and the second a more accurate bi‐linear stiffness model, are employed. The impact of baseline model complexity is then delineated. The LMS‐based methods are able to track the non‐linearity of the system to within 15% using this metric, with the error due primarily to filter convergence rates as the structural response changes regimes while undergoing the El Centro ground motion record. The use of a bi‐linear baseline model for the SHM problem is shown to result in error metrics that are at least 50% lower than those for the tangential baseline model. Errors of 5–15% with this L ₂ error norm are fairly stringent compared to the greater than 2 × changes in stiffness undergone by the structure, however, in practice the usefulness of the results is dependent on the resolution required by the user. The impact of sampling rate is shown to be negligible over the range of 200–1000Hz, along with the choice of LMS‐based SHM method. The choice of baseline model and its level of knowledge about the actual structure is seen to be the dominant factor in achieving good results. The methods presented require 2.8–14.0 Mcycles of computation and therefore could easily be implemented in real time. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

The observational discrimination of Friedmann-Lemaître models     

Y. Chu  J. Hoell  H. -J. Blome  W. Priester 《Astrophysics and Space Science》1988,148(1):119-130

It is the purpose of this paper to illustrate the interrelation between the problems of the ‘missing mass’, the galactic age and the cosmological constant A (or its equivalent quantum vacuum densityρ _v ). The inflationary picture of the early universe predicts that our present universe should have a very nearlyEuclidean metric. If we accept this concept, one would have to discriminate between two rather extreme Euclidean cosmological models:

1. The standard model with ∧=0 and a densityρ _c = 3H ₀ ² 8πG. There are difficulties ifH ₀≥5- km s^?1 Mpc^?1 and the galactic aget ₀≥14×10⁹ years.
2. The Euclidean Friedmann-Lemaître models with ∧>0, i.e., Δgt;0, i.e.,ρ _v =ρ _c ?ρ _o , whereρ _o is the present matter density, including the nonrelativistic dark matter. Hereρ _v ‘competes’ with the missing mass.

Measurements of apparent diameters of galaxies up to redshifts of 2 will permit one to discriminate between the models provided that size evolution of galaxies can be determined or neglected (see Figure 3).  相似文献   

Comparison of GRACE data and groundwater levels for the assessment of groundwater depletion in Jordan     

Tanja Liesch  Marc Ohmer 《Hydrogeology Journal》2016,24(6):1547-1563

Gravity Recovery and Climate Experiment (GRACE) derived groundwater storage (GWS) data are compared with in-situ groundwater levels from five groundwater basins in Jordan, using newly gridded GRACE GRCTellus land data. It is shown that (1) the time series for GRACE-derived GWS data and in-situ groundwater-level measurements can be correlated, with R ² from 0.55 to 0.74, (2) the correlation can be widely ascribed to the seasonal and trend component, since the detrended and deseasonalized time series show no significant correlation for most cases, implying that anomalous signals that deviate from the trend or seasonal behaviour are overlaid by noise, (3) estimates for water losses in Jordan based on the trend of GRACE data from 2003 to 2013 could be up to four times higher than previously assumed using estimated recharge and abstraction rates, and (4) a significant time-lagged cross correlation of the monthly changes in GRACE-derived groundwater storage and precipitation data was found, suggesting that the conventional method for deriving GWS from GRACE data probably does not account for the typical conditions in the study basins. Furthermore, a new method for deriving plausible specific yields from GRACE data and groundwater levels is demonstrated.  相似文献   

Copepod distribution as an indicator of epikarst system connectivity   总被引：2，自引：0，他引：2  

Tanja Pipan  David C. Culver 《Hydrogeology Journal》2007,15(4):817-822

The distribution of 27 copepod species was determined in 35 drips in four Slovenian caves (Dimnice, Postojna Planina Cave System, Škocjanske Jame, Županova Jama), and of ten species from 13 drips in one US cave (Organ Cave, West Virginia). The dripping water comes from epikarst, the skin of karst. A significant fraction of the copepod species found (nine species in Slovenia and three in West Virginia) occurred over a maximum linear extent of 100 m. These and other localized distributions probably resulted from colonization of epikarst by an ancestral surface population in a single location, with subsequent lateral spread in the direction of epikarst flow. This suggests that the distribution of copepods could potentially be used to trace major flow paths in epikarst without the need for the injection of dyes or other tracers.

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Résumé La distribution de 27 espèces de copépodes a été déterminée dans 35 zones de percolation de quatre grottes slovènes (Dimnice, système de grottes Postojna Planina, Škocjanske Jame, Županova Jama) et grace à dix espèces de 13 zones de percolation d’une grotte des Etats-Unis (Grotte Organ, Ouest de la Virginie). L’eau de percolation provient de l’épikarst, la partie supérieure du karst. Une fraction importante des espèces de copépodes trouvées (9 espèces en Slovénie et 3 dans l’Ouest de la Virginie) s’étendait sur une longueur maximum de 100 m. Ces dernières ainsi que d’autres distributions localisées étaient probablement issues de la colonisation par une population ancienne de surface, de zones localisées de l’épikarst, puis par une dispersion latérale dans la direction de l’écoulement dans l’épikarst. Ceci suggère que la distribution des copépodes pourrait potentiellement être utilisée pour identifier les principales trajectoires d’écoulement dans l’épikarst, sans utiliser l’injection de colorants ou d’autres traceurs.

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Resumen Se determina la distribución de 27 especies de copépodo en 35 gotas de cuatro cavernas de Eslovenia (Dimnice, Sistema de Caverna Planina Postojna, Jame Škocjanske, y Jama Županova), y de diez especies en 13 gotas de una caverna de Estados Unidos (Caverna órgano, Virginia Occidental). El agua que gotea se deriva del epikarst, la piel del karst. Una fracción significativa de las especies de copépodos encontradas (9 especies en Eslovenia y 3 en Virginia Occidental) se presentaron en una extensión linear máxima de 100 m. Estas y otras distribuciones localizadas resultaron probablemente de colonización del epikarst por poblaciones superficiales ancestrales en una sola localización, con una expansión lateral subsiguiente en la dirección de flujo epikárstico. Esto sugiere que la distribución de copépodos podría tener un uso potencial para trazar rutas de flujo principales en epikarst sin tener la necesidad de inyectar colorantes u otros trazadores.

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Hydrological analysis of Skradinski Buk tufa waterfall (Krka River,Dinaric karst,Croatia)     

Ognjen Bonacci  Ivo Andrić  Tanja Roje-Bonacci 《Environmental Earth Sciences》2017,76(19):669

The paper analyses complex hydrological behaviour of Skradinski Buk, the tufa waterfall, formed on the downstream part of the Krka River located in the coastal part of the Croatian Dinaric karst. This waterfall is the central point of the Krka National Park (KNP) proclaimed in 1985. Skradinski Buk is the seventh, final and the largest tufa barrier on the Krka River. Morphology of Skradinski Buk is composed of 17 unevenly distributed steps and dozens of small depressions. Natural waterfall morphology strongly influenced the complex waterfall hydrological regime. Additionally, hydrological regime is disturbed by the operation of the hydroelectric power plant (HEPP) Jaruga. This paper analyses characteristic (minimum, mean, maximum) annual water levels and discharges monitored at two hydrological stations (Skradinski Buk Gornji-SBG and Nacionalni Park-NP). SBG controls the inflow of water into the waterfall, while the NP is established in order to control the use of water from the HEPP Jaruga operation. It is concluded that the HEPP Jaruga does not comply with the agreement signed between the KNP and the HEPP Jaruga. The goal of the paper is to give detailed hydrological analysis of the Skradinski Buk, which should play the crucial role in the protection of this wonderful and very vulnerable phenomenon.  相似文献   

Suitability of linden and elder in the assessment of environmental pollution of Brestovac spa and Bor lake (Serbia)     

Tanja S. Kalinovic  Snezana M. Serbula  Jelena V. Kalinovic  Ana A. Radojevic  Jelena V. Petrovic  Mirjana M. Steharnik  Jelena S. Milosavljevic 《Environmental Earth Sciences》2017,76(4):178

The suitability of linden and elder as biomonitors was evaluated in the tourist zone of the Bor region well known for pyrometallurgical copper production. The concentrations of As, Cu, Pb and Zn in the soil, washed and unwashed leaves and roots of linden and elder were determined. The absorption of As, Cu, Pb and Zn from soil to roots and leaves, as well as the translocation of the studied elements from roots to leaves, was analysed. It was observed that the soil in the tourist zone of Bor (Bor lake and Brestovac spa) was greatly polluted with Cu and As. Linden and elder leaves can be used as a low-cost material for detection of As, Cu, Pb and Zn in the atmospheric deposition, which was concluded due to the amounts of these elements removed after a washing treatment. Thus, canopies of linden and elder might have an important role in the removal of the polluting substances from the air. The elder leaves were more suitable to be used for indication of environmental pollution with As, Cu and Pb than the linden leaves. The area of the Bor lake sampling site had higher air pollution with As and Pb than Brestovac spa, since greater amounts of As and Pb were washed off the linden and elder leaves from the Bor lake sampling site. The linden and elder used different adaptation strategies in conditions of the increased soil and air pollution. These strategies were based on different efficiencies of element absorption from the soil and on limited or efficient translocation of the studied elements from roots to leaves, and therefore, they have an important role in the biogeochemical cycling of the examined elements in the environment.  相似文献   

Oligoprenyl-curcumanes and other new aromatic isoprenoids from the 1.64 billion year old Barney Creek Formation     

Jochen J. Brocks  Tanja Bosak  Ann Pearson 《Organic Geochemistry》2009,40(7):795-801

Carbonaceous dolomites and shales of the 1.64 billion years (Ga) old Barney Creek Formation (BCF), McArthur Basin, northern Australia contain the oldest, clearly indigenous biomarkers. We describe three new series of regularly branched aryl isoprenoids with base ions at m/z 119, 161 and 175. The m/z 119 compounds were identified as a complete series of C₁₅–C₄₀ oligoprenyl-perhydro-ar-curcumenes (oligoprenyl-curcumanes). Their likely biogenic precursors are oligoprenyl-β-curcumenes that occur in a wide range of bacterial phyla.  相似文献   

Spatio-temporal distribution of floating objects in the German Bight (North Sea)     

Martin Thiel  Ivn A. Hinojosa  Tanja Joschko  Lars Gutow 《Journal of Sea Research》2011,65(3):368-379

Floating objects facilitate the dispersal of marine and terrestrial species but also represent a major environmental hazard in the case of anthropogenic plastic litter. They can be found throughout the world's oceans but information on their abundance and the spatio-temporal dynamics is scarce for many regions of the world. This information, however, is essential to evaluate the ecological role of floating objects. Herein, we report the results from a ship-based visual survey on the abundance and composition of flotsam in the German Bight (North Sea) during the years 2006 to 2008. The aim of this study was to identify potential sources of floating objects and to relate spatio-temporal density variations to environmental conditions. Three major flotsam categories were identified: buoyant seaweed (mainly fucoid brown algae), natural wood and anthropogenic debris. Densities of these floating objects in the German Bight were similar to those reported from other coastal regions of the world. Temporal variations in flotsam densities are probably the result of seasonal growth cycles of seaweeds and fluctuating river runoff (wood). Higher abundances were often found in areas where coastal fronts and eddies develop during calm weather conditions. Accordingly, flotsam densities were often higher in the inner German Bight than in areas farther offshore. Import of floating objects and retention times in the German Bight are influenced by wind force and direction. Our results indicate that a substantial amount of floating objects is of coastal origin or introduced into the German Bight from western source areas such as the British Channel. Rapid transport of floating objects through the German Bight is driven by strong westerly winds and likely facilitates dispersal of associated organisms and gene flow among distant populations.  相似文献   

An application of least-squares inverse analysis in kinetic interpretations of hydrous pyrolysis experiments     

S?ren B. Nielsen  Tanja Barth 《Mathematical Geology》1991,23(4):565-582

A least-squares inverse method is applied to the estimation of optimum kinetic parameters with statistical error bounds from concentration data obtained in isothermal hydrous pyrolysis experiments. The inverse method requires the specification of a data-parameter relationship (e.g., classical kinetic theory), the prior covariance matrices of data and parameter errors, as well as the prior central estimates of data and parameters. The reaction scheme considered is the common case of kerogen breakdown by Gaussian-weighted independent parallel first-order reactions and bitumen cracking by a single first-order reaction. The nonlinearity of the problem is reduced by a logarithmic transformation, which suggests a parameterization in terms of logarithmic concentrations, activation energies, and logarithmic Arrhenius factors. The linearized variance analysis is valid for the case studied, and the posterior covariance matrix reveals which parameters are constrained by the data. We find that the statistical errors in the average activation energy and the associated Arrhenius factor are strongly correlated. Hence, the parameters which determine the temperature dependence of the reaction rate have not been resolved independently. Furthermore, the kinetic results are very sensitive to the presence of a distribution of activation energies in kerogen breakdown. This distribution is not constrained by the data. As a consequence, neglecting the consideration of distributions of activation energies results in activation parameter values which are much too low. This is the major reason for the commonly encountered discrepancy between kinetic parameter values obtained from hydrous pyrolysis and micropyrolysis experiments, respectively.  相似文献