A shape-based heuristic for the detection of urban block artifacts in street networks

Street networks are ubiquitous components of cities, guiding their development and enabling movement from place to place; street networks are also the critical components of many urban analytical methods. However, their graph representation is often designed primarily for transportation purposes. This representation is less suitable for other use cases where transportation networks need to be simplified as a mandatory pre-processing step, e.g., in the case of morphological analysis, visual navigation, or drone flight routing. While the urgent demand for automated pre-processing methods comes from various fields, it is still an unsolved challenge. In this article, we tackle this challenge by proposing a cheap computational heuristic for the identification of "face artifacts", i.e., geometries that are enclosed by transportation edges but do not represent urban blocks. The heuristic is based on combining the frequency distributions of shape compactness metrics and area measurements of street network face polygons. We test our method on 131 globally sampled large cities and show that it successfully identifies face artifacts in 89% of analyzed cities. Our heuristic of detecting artifacts caused by data being collected for another purpose is the first step towards an automated street network simplification workflow. Moreover, the proposed face artifact index uncovers differences in structural rules guiding the development of cities in different world regions.Comment: Zenodo: https://doi.org/10.5281/zenodo.8300730 ; GitHub: https://github.com/martinfleis/urban-block-artifact

Measuring urban form : overcoming terminological inconsistencies for a quantitative and comprehensive morphologic analysis of cities

Unprecedented urbanisation processes characterise the Great Acceleration, urging urban researchers to make sense of data analysis in support of evidence-based and large-scale deci- sion-making. Urban morphologists are no exception since the impact of urban form on funda- mental natural and social patterns (equity, prosperity and resource consumption’s efficiency) is now fully acknowledged. However, urban morphology is still far from offering a comprehensive and reliable framework for quantitative analysis. Despite remarkable progress since its emergence in the late 1950s, the discipline still exhibits significant terminological inconsistencies with regards to the definition of the fundamental components of urban form, which prevents the establishment of objective models for measuring it. In this article, we present a study of existing methods for measuring urban form, with a focus on terminological inconsistencies, and propose a systematic and comprehensive framework to classify urban form characters, where ‘urban form character’ stands for a characteristic (or feature) of one kind of urban form that distinguishes it from another kind. In particular, we introduce the Index of Elements that allows for a univocal and non-interpretive description of urban form characters. Based on such Index of Elements, we develop a systematic classification of urban form according to six categories (dimension, shape, spatial distribution, intensity, connectivity and diversity) and three conceptual scales (small, medium, large) based on two definitions of scale (extent and grain). This framework is then applied to identify and organise the urban form characters adopted in available literature to date. The resulting classification of urban form characters reveals clear gaps in existing research, in particular, in relation to the spatial distribution and diversity characters. The proposed framework reduces the current inconsistencies of urban morphology research, paving the way to enhanced methods of urban form systematic and quantitative analysis at a global scale

Blockchain Technology as a Means for Brand Trust Repair – Empirical Evidence from a Digital Transgression

Though much discussion in the realm of blockchain revolves around the concept of trust, research examining blockchain technology as a means for brand trust repair is still at an initial stage. This study conducts an experiment that analyzes blockchain technology as a substantive response to a data breach within a global business-to-consumer information systems application. Thereby, the present study expands trust repair theories to the context of blockchain and branding. Research results indicate that the use of blockchain technology as a reaction to a digital transgression may be able to reinstate brand trust, having a superior impact compared to an approach that uses a centrally managed information systems platform to restore brand trust. Overall, study results suggest that the use of blockchain technology can be an effective component of brand trust repair strategies in the digital space

Oxidation and Coordination Chemistry of En Ligand Complexes under Weakly Coordinating Conditions

This thesis deals with the chemistry of substituent-free En ligand complexes (E = P, As, Sb, Bi) under weakly coordinating conditions. It consists of the following four parts in which different topics are elucidated: 1. Coordination chemistry of En ligand complexes towards monovalent metal cations M+ (M = Cu, Ag, Tl) featuring weakly coordinating anions (WCAs) 2. Oxidation chemistry of selected En ligand complexes and stabilization of the resulting cationic species by WCAs 3. Supramolecular coordination chemistry of trinuclear Cu(I) complexes stabilized by polyphosphine ligands and their reactivity towards En ligand complexes 4. Reactivity of En ligand complexes towards the trinuclear Lewis acid [(o-HgC6F4)3

momepy : Urban morphology measuring toolkit

Urban morphology is the area of urban studies that explores the physical form of cities in space and the way it changes in time in relation to the agents of such change (Kropf, 2017). The discipline is based on the analysis of space, traditionally mostly visual and qualitative (Dibble et al., 2015); its objects are the fundamental elements of urban form (building, plot, street) (Moudon, 1997) as well as a range of analytical constructs such as axial maps (Ariza-Villaverde, Jiménez-Hornero, & Ravé, 2013) or proximity bands (Araldi & Fusco, 2019). The increased availability of morphological data and computational power have led in time to more emphasis on quantitative forms of analysis, and the emergence of Urban Morphometrics (UMM) (Dibble et al., 2017): this approach describes urban form via the systematic and comprehensive measurement of its morphological characters. Since UMM analysis is addressed both in-depth and at large scale, it is grounded on the intensive use of GIS software (proprietary ArcGIS, MapInfo, open-source QGIS) either through built-in processing tools or specific plugins like Urban Network Analysis (Sevtsuk & Mekonnen, 2012) or Place Syntax Tool (Ståhle, Marcus, & Karlström, 2005). However, essential functions to conduct such measurements on specific urban morphometric characters or processes such as morphological tessellation, are not always available: current plugins offer only a limited number of functionalities as they are mainly application or case-specific. This paper is hereby proposing momepy, a Python toolkit which aims to overcome such limitations by enabling a systematic in-depth analysis of urban form, to comprehensively include a wide range of measurable characters, with a prospect of expanding future development due to its open-source nature and independence on proprietary software or operating systems. The development of momepy is timely, as the role of measurable characters is vital to recognize form-based patterns and establish descriptive and analytical frameworks of human settlements, in the “age of urbanization”

Stau as the Lightest Supersymmetric Particle in R-Parity Violating SUSY Models: Discovery Potential with Early LHC Data

We investigate the discovery potential of the LHC experiments for R-parity violating supersymmetric models with a stau as the lightest supersymmetric particle (LSP) in the framework of minimal supergravity. We classify the final states according to their phenomenology for different R-parity violating decays of the LSP. We then develop event selection cuts for a specific benchmark scenario with promising signatures for the first beyond the Standard Model discoveries at the LHC. For the first time in this model, we perform a detailed signal over background analysis. We use fast detector simulations to estimate the discovery significance taking the most important Standard Model backgrounds into account. Assuming an integrated luminosity of 1 inverse femtobarn at a center-of-mass energy of 7 TeV, we perform scans in the parameter space around the benchmark scenario we consider. We then study the feasibility to estimate the mass of the stau-LSP. We briefly discuss difficulties, which arise in the identification of hadronic tau decays due to small tau momenta and large particle multiplicities in our scenarios.Comment: 26 pages, 18 figures, LaTeX; minor changes, final version published in PR

On new alkaline‐earth hexafluorogermanates as host structures for UV phosphors

Two new hexafluorogermanate dihydrates, viz. SrGeF6 ⋅ 2H2O and CaGeF6 ⋅ 2H2O, were synthesised from aqueous solutions; their crystal structures were refined in space group P21/n (SrGeF6 ⋅ 2H2O: a=5.9605(2) Å, b=9.6428(3) Å, a=10.9866(3) Å and β=99.1590(10), Z=4, 5122 refl., 104 param., R1=0.0195, wR2=0.0470; CaGeF6 ⋅ 2H2O: a=5.8472(5) Å, b=10.5099(9) Å, c=9.6267(9) Å and β=103.521(3), Z=4, 4756 refl., 101 param., R1=0.0224, wR2=0.0616). Upon doping with Eu2+ luminescence in the NUV regime was observed. The crystal structures of CaGeF6 and MgGeF6 could be solved and refined via Rietveld refinement from powder samples gained by thermal decomposition of the respective hydrates; both compounds adopt the LiSbF6 structure type (CaGeF6: a=5.4099(5) Å, c=13.9835(13) Å, Z=3, Rwp=0.0291, RBragg=0.0142; MgGeF6: a=5.1219(2) Å, c=13.0851(7), Z=3, Rwp=0.034, RBragg=0.01). Further, the luminescence of MgGeF6 ⋅ 6H2O:Eu2+, which emits light in the violet to blue regime, is reported

Time Slot Management in Attended Home Delivery

Many e-tailers providing attended home delivery, especially e-grocers, offer narrow delivery time slots to ensure satisfactory customer service. The choice of delivery time slots has to balance marketing and operational considerations, which results in a complex planning problem. We study the problem of selecting the set of time slots to offer in each of the zip codes in a service region. The selection needs to facilitate cost-effective delivery routes, but also needs to ensure an acceptable level of service to the customer. We present two fully-automated approaches that are capable of producing high-quality delivery time slot offerings in a reasonable amount of time. Computational experiments reveal the value of these approaches and the impact of the environment on the underlying trade-offs