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Cartography and Geomedia
Get PDFThe Special Issue “Cartography and Geomedia” presents a view of cartography as a combination of technology, science, and art, with a focus on the development of geomedia in a geomatic and design-based context. Individual considerations are presented according to the following topics: efficiency of mapping techniques; historical cartographic works in a geomedial context; cartographic pragmatics for cultural heritage, teaching, and tourism; and pragmatism in gaming cartography. The main conclusion is that the two approaches to learning, revealing, and understanding geographic phenomena—starting from a specific geographical phenomenon and starting from maps and geomedia to understand geographical space—have their pragmatic strengths
Bathymetrische Untersuchung zur Bewertung und Vorhersage der Sedimentrate im Kainji-Stausee auf der anderen Seite des Niger in Nigeria
Get PDFSedimentation and siltation are gradual and continuous processes that fill up water bodies, especially reservoirs. The menace of sediment deposits can cause flooding or dam failure if left unchecked. This will be pronounced globally “especially in developing countries” due to the rising sea levels caused by climate emergencies, which will further exacerbate the destructive power of flooding. Therefore, science, international cooperation, preparedness and early action must be pivotal to safer people and communities (Antonio, 2021). To this end, accurately determining or estimating the amount of sediment deposits in a reservoir and possibly forecasting the future reservoir depth surface has been a global challenge if the activities of sedimentation remain the same. To ensure proper monitoring and management of reservoir, sounding operations to determine the amount of deposited lacustrine material to be dredged should be conducted regularly. Hence, bathymetric and sedimentation surveys were conducted in 2020 using a dual-frequency (20/200 kHz) echo sounder system in the Kainji Reservoir in New Bussa, Niger State, Nigeria. A Hi-Target V30 dual-frequency Differential Global Positioning System (DGPS) was used to delineate the reservoir shoreline at some strategic locations, including tidal measurement. The data were merged to provide detailed visualization and analyses of current depth distribution and thickness and to estimate the volume of lacustrine sediment, time average sediment accumulation rates, long-term average annual sediment flux, and water storage capacity. A recent day reservoir stand-alone information system was generated from 200 kHz sounding data. Linear regression of the reservoir depths was assessed from 1990 bathymetric datasets and 2020 datasets using profiles and cross-sections. The results show that the maximum observed depth is 71.2 m, indicating a 7.53% loss in depth from the 1990 archived data and a 16.24% depth loss to sedimentation from 1968 to 2020. The calculated long-term average sediment accumulation rates were used to model sediment infilling and the projected lifetime of the reservoir. The outcome from the echo sounder datasets suggests that the basin has a projected lifetime of 85.65 years due to sediment load. Furthermore, Markov chain and cellular automata (MC – CA) were used to forecast the future bathymetric surface of 2050, but the final surface generated some artefacts but well-predicted depths were achieved. Hence, Cellular Automata and Gradient Boosting Regression (CA – GBR) were specifically integrated for this research to model future bathymetric surfaces to evaluate the outcome of CA – Markov chains. The results show that CA – GBR effectively forecasted the future bathymetric surface of 2050 without any artefacts at a 95.7% accuracy rate. Furthermore, to investigate the scientific reasons for the high sedimentation rate in the study area, first, land use land cover classification was conducted to assess the land-use changes using Landsat data from 1990, 2005, and 2020 with five classification schemes: water, vegetation, built-up, forest, and bare-ground. The results suggested that forest and vegetation have lost a greater percentage of their area to bare ground, giving rise to erosion because the soil loses its resistivity over time without adequate vegetation cover. Second, drainage network and catchment area analyses were conducted. The results show that the catchment has 1 to 6 stream orders and 28 subbasins, again indicating a mass movement of sediment from the catchment area to the central basin. Third, the Universal Soil Loss Equation (USLE) model was employed to estimate the soil loss in ton/acre/year via rill and sheet erosion into the reservoir. The results show a high rate of soil loss of calculated annual sediment loss from USLE of 5.6% greater than the estimated yearly sediment flux using a low-frequency echo sounder. The small change between USLE and low-frequency sediment estimation suggests that USLE can be used to validate low-frequency lacustrine sediment measurements. Finally, the flood impact vulnerability map was modelled with a maximum elevation of 137 m above mean sea level. The results indicated that all the communities within 1500 km from the river centre are in great danger of flooding, while others are either medium- or low-risk and safe zones
Das Zentrum der Agglo : die städtebauliche Konfiguration transformativer Zentren in der Agglomeration Zürich
Get PDFDie vorliegende Untersuchung befasst sich mit den Zentren der Agglomeration Zürich und ihren Merkmalen. Ausgangspunkt der Untersuchung sind gegenwärtige Transformationsprozesse, deren Dynamik sich besonders stark in den Zentren wachsender Agglomerationsgemeinden entfaltet. Anleitendes Forschungsinteresse sind das Herausarbeiten von städtebaulichen und sozialräumlichen Charakteristika der Zentren in der Agglomeration Zürich, sowie davon ausgehend die Formulierung von Handlungsempfehlungen für eine Zentren-orientierte Siedlungsentwicklung in transformativen Agglomerationsräumen.
In einem ersten Teil wird das theoretische Fundament, bestehend aus Ansätzen der relationalen Raumtheorie, städtebaulicher Analyse-Raster für Zentrum und Peripherie, Urbanität und öffentlicher Raum, der Konzeption der Zwischenstadt und dem Modell des Transit-oriented Development, dargelegt. Anschliessend folgt eine detaillierte städtebauliche Analyse der Zentren der drei Untersuchungsräume Thalwil, Schlieren und Wallisellen in der Agglomeration Zürich.
Dabei verdichtet sich der Kern der Untersuchung zunehmend auf das Bahnhofsumfeld der drei Zentren. Zunächst liegt der Fokus auf deren Verortung. Diese ist mitunter nicht eindeutig. In allen drei Untersuchungsräumen hat sich das Zentrumsgebiet von den historischen Ortskernen wegbewegt. Mit dem Bau von Bahnhöfen ausserhalb des ehemaligen Ortsgebiets hat sich über die Jahrzehnte im Zusammenhang mit der Industrialisierung, des Bevölkerungswachstums und der Zersiedelung in den Agglomerationsräumen ein neuer Ort der Zentralität um das Bahnhofsumfeld herausgebildet.
Im Zuge der Transformationsprozesse wird nun in den drei Gemeinden die «Rückseite» des Bahnhofs als erweitertes Zentrumsgebiet erschlossen. Dort wurden mit Areal-Entwicklungen und freiräumlichen Aufwertungen Attraktoren geschaffen, die eine Verbindung über die Bahntrassen hinweg zur zentralen stadträumlichen Aufgabe machen. In der Realität sind die Unterführungen und Passerellen allerdings reine funktionale Nicht-Orte (Marc Augé). In einem abschliessenden Teil werden daher planerische Handlungsansätze formuliert, wie sich diesem städtebaulichen und sozialräumlichen Missstand begegnen liesse.The present study deals with the centers of the Zurich agglomeration and their characteristics. Current transformation processes, particularly the dynamics which unfold powerfully in the centers of growing agglomeration communities, mark the starting point of the investigation. Inductive research interest is the elaboration of urban planning and socio-spatial characteristics of the centers in the Zurich agglomeration, as well as the formulation of recommended actions for a center-oriented settlement development in transformative agglomeration areas.
The first part investigates the theoretical foundation, touching on approaches of the relational theory of space, and urban planning analysis patterns for the terms center and periphery, urbanity and public space. Further, the conception of the Zwischenstadt and the model of transit-oriented development will be presented. This is followed by a detailed urban design analysis of the centers of the three study areas, Thalwil, Schlieren and Wallisellen, in the Zurich agglomeration.
The primary focus of this investigation is the area around the train station of the centers. The central district has moved away from the historic town centers in all three study areas. With the construction of train stations outside the former community boundaries, a new place of centrality has developed. Reasons for that are industrialization, population growth and urban sprawl over the last decades.
These processes result in the «backside» of the train station now being developed as an extended central area in all three communities. Area developments result in upgrades of public spaces. In reality, however, the underpasses and passages are functional non-spaces (Marc Augé). The concluding chapter frames an answer on possible planning approaches for how this urban development and socio-spatial deficit might be solved
Enjoying climate change: Jouissance as a political factor
Get PDFIn this paper, we explore this dissonance between knowing and acting that produces the current climate deadlock by focusing on ‘enjoyment’ as a political factor. The enjoyment that infuses the climate change consensus and climate activism stands as an avatar for the wider impasse that characterizes most attempts to inflect the trajectory of the future away from ‘accumulation for accumulation sake’ and its associated socio-ecological catastrophe. Considering enjoyment as a political factor might open avenues for re-framing the impasse of the present socio-ecological condition. We engage the Lacanian notion of enjoyment (jouissance). Our overall argument is that climate, and its change, is not only a threat to the world, but also something that is enjoyed in one way or the other. To illustrate the Lacanian take on enjoyment, we will differentiate between two dominant strands of enjoying climate change: First, a passionate engagement in destroying Nature based on an imperative to enjoy fossil fuels and what they metonymically stand for, and second, an equally passionate commitment to saving Nature based on an imaginary enjoyment that stems from renunciation and sacrifice. The paper proceeds by arguing for the need to traverse the fantasies that sustain the very deadlock of the current situation, a process that requires re-scripting the process of political subjectivation and our libidinal attachments to the enjoyment of climate change
A Three-Stage Nonparametric Kernel-Based Time Series Model Based on Fuzzy Data
Get PDFIn this paper, a nonlinear time series model is developed for the case when the underlying time series data are reported by
fuzzy numbers. To this end, we present a three-stage nonparametric kernel-based estimation procedure for the center as well as the left and right spreads of the unknown nonlinear fuzzy smooth function. In each stage, the nonparametric Nadaraya–Watson estimator is used to evaluate the center and the spreads of the fuzzy smooth function. A hybrid algorithm is proposed to estimate the unknown optimal bandwidths and autoregressive order simultaneously. Various goodness-of-fit measures are utilized for performance assessment of the fuzzy nonlinear kernel-based time series model and for comparative analysis. The practical applicability and superiority of the novel approach in comparison with further fuzzy time series models are demonstrated via a simulation study and some real-life applications
Urban Building Energy Modelling with Combinatorial Optimisation and Microsimulation: Application and Policy Analysis for Hamburg, Germany
Get PDFUrban Building Energy Models (UBEMs) are representations of building stocks. They can be used by analysts and decision makers in government, private companies, NGOs, and, if made publicly accessible, by the public at large. Their purpose is the energy analysis of the building sector – as it is, as it could and should be in the future, and paths to get there. Insofar as UBEMs are the basis for policy measures that affect many actors in the building sector they play an important role in those actors’ communications and negotiations.
In the last two decades, it has become obvious that UBEMs need to explicitly account for space, just as they need to represent the micro-level, i. e. individual buildings. The analysis of centralised heat supply (district heating) calls for spatial analysis. Renewable energies are often used most effectively in decentralised fashion. The interaction of heat demand and supply unfolds at the level of the urban neighbourhood. Indeed, today’s UBEMs are most often defined at the level of the individual building (though in publications, buildings are often clustered for data protection).
UBEMs come in different forms. Until recently, they were often created ad hoc for a specific research project or for an individual consulting service to local, regional or national government. The last few years have seen such models in more formalised fashion and made publicly accessible, as “heat cadastres” (“Wärmekataster”, as in the city-state of Hamburg), or “Heat Atlas” (“Wärmeatlas”, as in the federal Land Bavaria). These cadastres and atlases contain a variety of energy-related information, like buildings, infrastructure, heat and power generating stations, waste heat sources and more. In this thesis, I focus on the residential building stock and its heat demand.
The major challenge in creating a UBEM is the availability of data relating to the building stock. In Germany, there is a variety of data sources with different detail on building characteristics and at different levels of aggregation. Accordingly, UBEMs tend to be created with a Top-Down or a Bottom-Up approach. In simple terms, the former distributes total energy consumption at the city level onto all buildings according to their size. The latter makes use of building typologies and represents individual building characteristics and their specific heat demand by assigning “archetypes” to individual buildings. The Top-Down approach has the drawback of little flexibility in analysing measures that address individual building characteristics. UBEMs of the Bottom-Up type often overestimate total consumption as a consequence of how building types are defined and assigned to individual buildings.
I propose a hybrid approach, based on combinatorial optimisation, inspired and heavily borrowing techniques from the field of spatial microsimulation. My case study is Hamburg. I use three main data sources: the digital building cadastre (ALKIS), 100m Census raster cells, and a sample of building energy audits. When aggregated, my UBEM comes within a couple of percent of consumption data for all of Hamburg. As a micro-model with detail at the building level, it offers the flexibility to analyse various cases and scenarios. I illustrate a number of different applications of my UBEM that show how its main features – the micro-level, the georeferencing (each building with its geographic coordinates), and the consumption-adjusted heat demand – facilitate the analysis of a spectrum of energy policy measures.Urban Building Energy Models (UBEMs) sind Datenmodelle, die Gebäudebestände abbilden und von Analysten und Entscheidungsträgern in Behörden, Wirtschaft, NGOs und, falls öffentlich zugänglich gemacht, von der breiten Öffentlichkeit verwendet werden können. Sie dienen der energetischen Analyse des Gebäudesektors, sowohl was seinen Ist-Zustand, als auch, was seine Ziel-Zustände und Wege dorthin betrifft. Als Grundlage für Politikmaßnahmen der öffentlichen Hand, die viele Akteure berühren, fällt UBEMs eine wichtige Rolle in deren Verständigung zu.
In den letzten zwei Jahrzehnten ist die Notwendigkeit für die explizite Darstellung des Raums in solchen Modellen deutlich geworden, ebenso wie die explizite Berücksichtigung der „Mikro“-Ebene. Die Analyse der netzgebundenen Wärmeversorgung erfordert die räumliche Betrachtung. Erneuerbare Energien werden oft günstig dezentral genutzt. Das Zusammenspiel zwischen Angebot und Nachfrage erfolgt auf der Ebene des Quartiers. UBEMs werden heute meist auf der Ebene des einzelnen Gebäudes definiert (wobei in Veröffentlichungen die Gebäude aus Gründen des Datenschutzes in Clustern oder Gruppen dargestellt werden).
Solche UBEMs gibt es in unterschiedlichen Formen. Bis vor kurzem wurden sie vielfach ad hoc für ein bestimmtes Forschungsprojekt oder als Dienstleistung für lokale, regionale oder nationale Verwaltungen erstellt. In den letzten Jahren sind solche Modelle mehr formalisiert und öffentlich zugänglich gemacht worden, als „Wärmekataster“ (z.B. in Hamburg) oder „Wärmeatlas“ (z. B. in Bayern). Diese Kataster und Atlanten können eine Vielzahl von energiebezogenen Informationen abbilden – Gebäude, Infrastruktur, Energieerzeuger, Abwärmequellen und mehr. Darin können sie über ein UBEM hinausgehen. In meiner Arbeit konzentriere ich mich auf den Wohngebäudebestand und dessen Wärmebedarf.
Die große Herausforderung bei der Erstellung eines UBEMs ist die Verfügbarkeit von Daten zum Gebäudebestand. In Deutschland gibt es eine Vielzahl von Quellen in unterschiedlicher Detailschärfe und auf unterschiedlichen Aggregationsebenen. Dementsprechend werden sowohl der „Top-Down“- als auch der „Bottom-Up“-Ansatz bei der Erstellung von UBEMs verfolgt. Ersterer verteilt (vereinfacht gesprochen) den Gesamtenergieverbrauch auf Stadtebene auf alle Gebäude entsprechend ihrer Größe; letzterer nutzt Gebäudetypologien, um energetische Merkmale einzelner Gebäude abzubilden und ihnen typische spezifische Wärmebedarfswerte zuzuordnen. Das Problem des „Top-Down“ Ansatzes ist seine mangelnde Flexibilität, wenn es um die Analyse von Maßnahmen geht, die detaillierte Gebäudeeigenschaften adressieren. UBEMs mit „Bottom-Up“ Ansatz dagegen überschätzen oft den Gesamtverbrauch aufgrund der Art und Weise, wie Gebäudetypen definiert und einzelnen Gebäuden zugeordnet werden.
Ich schlage einen hybriden Ansatz vor, der auf kombinatorischer Optimierung und Methoden der räumlichen Mikrosimulation basiert. Mein Anwendungsfall ist Hamburg. Ich verwende hauptsächlich drei Datenquellen: Das digitale Gebäudekataster, 100-Meter-Zensus-Rasterzellen sowie eine Stichprobe von Gebäude-Energieausweisen. Aggregiert kommt mein UBEM sehr nah an die Verbrauchsdaten auf Stadtebene heran. Als Mikromodell mit Detail auf Gebäudeebene bietet es die Flexibilität für die Analyse unterschiedlicher Fragestellungen und Szenarien. Ich illustriere verschiedene Anwendungen des UBEM, die zeigen, wie seine Hauptmerkmale – die „Mikro“-Ebene, Georeferenzierung (jedes Gebäude mit seinen geografischen Koordinaten) und verbrauchskorrigierter Wärmebedarf – eine Bandbreite energiepolitischer Analysen ermöglichen.Bundesministerium für Wirtschaft und Energie (BMWi
Entwicklung momententragfähiger Eckverbindungen für pultrudierte GFK-Profile
Get PDFStabtragwerke können durch den Einsatz von momententragfähigen Anschlüssen effizienter gestaltet werden, da die Momente im Tragwerk gleichmäßiger verteilt werden. Dadurch können Material, Eigengewicht und Kosten eingespart werden. Im Stahl-, Holz- und Stahlbetonbau ist es Stand der Technik, biegesteife Anschlüsse zu verwenden. Diese normativ geregelten biegesteifen Anschlüsse haben für die Baustatik den Vorteil, dass die Steifigkeit des Anschlusses nicht berechnet werden muss. Der Anschluss muss nur für das resultierende Moment nachgewiesen werden. Für diese ökonomische Bauweise gibt es im Bauwesen für Halbzeuge aus Faser-Kunststoff-Verbunden (FKV) derzeit generell keine normative Grundlage. Für Halbzeuge aus FKV werden im Bauwesen i.d.R. Glasfasern verwendet. Für diese glasfaserverstärkten Kunststoffprofile (GFK-Profile) existieren Anwendungsregeln für gelenkige Verbindungen, aber nicht für momententragfähige bzw. biegesteife Verbindungen und genau hier setzt diese Arbeit an. Es werden momententragfähige, rechtwinklige Eckverbindungen mit GFK-Profilen für Stütze und Riegel untersucht. Die GFK-Profile weisen die meisten Fasern in Richtung der Stabachse auf. Der Kunststoff schützt die Fasern nur vor Umwelteinflüssen und stabilisiert sie gegen Knicken, die Kräfte werden jedoch von den Fasern aufgenommen. Daher muss die Kraft von den Fasern über Verbindungsmittel und Fügebauteile in die Fasern des anderen Bauteils geleitet werden. Folglich muss die Kraft über eine geringere Anzahl von Querfasern der Profile in das Verbindungsmittel eingeleitet werden. Dies wirkt sich in erster Linie auf das aufnehmbare Moment aus. Aber auch die Rotation der Eckverbindung muss gering gehalten werden und dies bei einem ca. 12-fach geringeren E-Modul von GFK-Profilen im Vergleich zu Stahlprofilen. Im Stahlbau gibt es die Möglichkeit, eine Verbindung nach ihrer Steifigkeit zu klassifizieren. Für GFK-Profile gibt es jedoch keine Ansätze.
Auf der Grundlage einer umfangreichen Literaturrecherche werden in der vorliegenden Arbeit Eckverbindungsvarianten für die beiden im Bauwesen häufig verwendeten Profilquerschnitte Hohlkasten- und Doppel-T-Querschnitte entwickelt. Die Varianten werden für querschnittsgleiche Stützen und Riegel entwickelt, wobei die Stütze nicht über den Riegel hinausragt (L-förmige Verbindung). Als Fügebauteile werden Stahlbleche verwendet, da aufgrund der Isotropie des Materials einer sich ständig ändernden Kraftrichtung immer gleiche Werkstoffeigenschaften gegenüberstehen. Bei den Varianten mit Hohlkastenprofilen werden Selbstbohrschrauben (SBS) zur Verbindung der Profile mit den Stahlblechen eingesetzt. SBS haben den Vorteil, dass sie nicht vorgebohrt werden müssen und im Gegensatz zu Stahlbauschrauben keine Mutter aufgesetzt werden muss. Dies wäre bei den Hohlkastenprofilen problematisch gewesen, da bei der Verbindung des zweiten Profils mit dem Fügebauteil nicht in das Profil eingegriffen werden kann. Die Varianten mit Doppel-T-Profilen werden mit Stahlbauschrauben entwickelt, da hier die Problematik mit der Mutter nicht besteht und die Klemmdicke der zu verbindenden Bauteile für SBS zu groß war. In Anlehnung an die Stahlbaunormung und die Anwendungsregeln für GFK werden die Verbindungen für eine möglichst hohe Biegetragfähigkeit ausgelegt, so dass ein Versagen möglichst im GFK-Profil außerhalb der Verbindungsmittel auftritt.
Die entwickelten Eckverbindungen werden experimentell im Maßstab 1:1 auf ihr Momenten-Rotations-Verhalten untersucht. Die Ergebnisse werden mit der rechnerischen Momententragfähigkeit verglichen und anhand der aufgetretenen Schäden auf Plausibilität überprüft. Die Ergebnisse dienen der anschließenden Verifizierung der numerischen Modelle. Diese Modelle werden mit der Finite-Elemente- Methode mit dem Programm ANSYS untersucht. Zur Abbildung des GFK werden anstelle der klassischen Laminattheorie ein elastisch-plastisches Materialgesetz verwendet. Dadurch werden deutlich weniger Materialparameter benötigt, die sonst entweder aufwändig experimentell ermittelt oder angenommen werden müssten. Die Momenten-Rotations-Charakteristik der Eckverbindungen können hinreichend genau abgebildet werden.
In einem weiteren Schritt werden die Eckverbindungen mit einem Voutenblech ergänzt und numerisch untersucht. Die Steifigkeit der Verbindungen kann bei einigen Varianten deutlich gesteigert werden. Die Klassifizierung der Eckverbindungen nach ihrer Steifigkeit erfolgt nach den Regeln des Stahlbaus. Die Anwendbarkeit wird belegt, indem in der numerischen Simulation das Material der Profile von GFK auf Stahl geändert wird. Für die Varianten mit GFK-Hohlkastenprofilen wird ein modifizierter Ansatz zur Klassifizierung nach der Steifigkeit vorgeschlagen.Linear structural elements can be designed more efficiently by using rigid connections, as the moments in the structure are distributed more evenly. This can save material, dead weight and costs. In steel, timber and reinforced concrete structures, it is state of the art to use rigid connections. These standardised connections have the advantage for structural analysis that the stiffness of the connection does not have to be calculated. The connection only has to be checked for the resulting moment. At present, there is generally no normative basis for this economical construction method in the building industry for semi-finished products made of fibre-reinforced plastic composites (FRP). Glass fibres are generally used for semi-finished products made of FRP in the construction industry. For these glass-fibre reinforced plastic profiles (GRP profiles), application rules exist for hinged connections, but not for rigid connections, and this is exactly where this work starts. Moment-bearing, right-angled corner connections with GRP profiles for columns and transoms are to be investigated. The GRP profiles have most of the fibres in the direction of the bar axis. The plastic only protects the fibres from environmental influences and stabilises them against buckling, but the forces are absorbed by the fibres. Therefore, the force must be transferred from the fibres to the fibres of the other component via connecting means and joining components. Consequently, the force must be introduced into the lanyard via a smaller number of transverse fibres of the profiles. This primarily affects the moment bearing capacity. But the rotation of the corner joint must also be kept low and this with an E-modulus of GRP profiles that is approx. 12 times lower than that of steel profiles. In steel structures, it is possible to classify a connection according to its stiffness. However, there are no approaches for GRP profiles.
Based on an extensive literature research, corner connection variants are developed in the present work for the two profile cross-sections frequently used in the building industry, hollow box and double-T cross-sections. The variants are developed for columns and ledgers with the same cross-section, whereby the column does not project beyond the ledger (L-shaped connection). Steel plates are used as joining components, since due to the isotropy of the material, a constantly changing direction of force is always opposed by the same material properties. In the variants with box girder profiles, self-tapping screws (SBS) are used to connect the profiles to the steel plates. SBS have the advantage that they do not have to be pre-drilled and, in contrast to steel structures screws, no nut has to be put on. This would have been problematic with the box girder profiles, as it is not possible to interfere with the profile when connecting the second profile to the joining component. The variants with double-T profiles were developed with structural steel bolts, avoiding the problem with the nut and the restricted clamping thickness of the components joined by SBS. Following the steel construction standard and the application rules for GRP, the connections were designed for the highest possible bending load capacity, so that failure occurs in the GRP profile outside the fasteners, if possible.
The developed corner connections were examined experimentally on a scale of 1:1 for their moment-rotation behaviour. The results were compared with the calculated moment capacity and checked for plausibility based on the damage that occurred. The results were used for the subsequent verification of the numerical models. These models were examined using the finite element method with the ANSYS programme. To represent the GRP, an elastic-plastic material law was used instead of the classical laminate theory. This meant that significantly fewer material parameters were required, which would otherwise either have to be determined experimentally at great expense or assumed. The moment-rotation characteristics of the corner joints could be mapped sufficiently accurately.
In the last step, the corner connections were supplemented with a cove plate and numerically investigated. The stiffness of the connections could be significantly increased for some variants. The classification of the corner connections according to their stiffness was carried out according to the rules of steel construction. The applicability was proven by changing the material of the profiles from GRP to steel in the numerical simulation. For the variants with GRP box girder profiles, a modified approach to classification according to stiffness was proposed
Social media insights on public perception and sentiment during and after disasters: The European floods in 2021 as a case study
Get PDFDetecting and collecting public opinion via social media can provide near real-time information to decision-makers, which plays a vital role in urban disaster management and sustainable development. However, there has been little work focusing on identifying the perception and the sentiment polarity expressed by users during and after disasters, particularly regional flood events. In this article, we comprehensively analyze tweets data related to the “European floods in 2021” over time, topic, and sentiment, forming a complete workflow from data processing, topic modeling, sentiment analysis, and topic and sentiment prediction. The aim is to address the following research questions: (1) What are the public perception and main concerns during and after floods? (2) How does the public sentiment change during and after floods? Results indicate that there is a significant correlation between a flood's trend and the heat of corresponding tweets. The three topics that receive the most public concern are: (1) climate change and global warming; (2) praying for the victims: and (3) disaster situations and information. Negative sentiments are predominant during the floods and will continue for some time. We tested five different classifiers, of which TextCNN-attention turned out to deliver the best predictions in topic and sentiment prediction, and performed well for sparse flood tweets, it can be used to predict the topic and sentiment polarity of a single tweet in real-time during the flood events. Our findings can help disaster agencies to better understand the dynamics of social networks and develop stronger situational awareness towards a disaster, which can contribute to scientifically justified decision-making in urban risk management and also meet the challenges associated with the global sustainable development goal 11 (SDGs) on Sustainable Cities and Communities
City Planning, Urban Initiatives and Health
Get PDFStadtplanung und Public Health sind zentrale Handlungsfelder, um Stadtentwicklung aus einer gesundheitlichen Perspektive zu betrachten. In beiden Handlungsfeldern spielen Politik und Verwaltung ebenso wie urbane Initiativen eine gestaltende Rolle. Das Handeln richtet sich auf die gemeinsamen übergeordneten Themenlinien Zukunftsfähigkeit, soziale Gerechtigkeit und umweltbezogene Gerechtigkeit aus. Diese Gemeinsamkeiten spiegeln sich in unterschiedlichen Memoranden wider. Trotz dieser gemeinsamen Basis von Stadtplanung und Gesundheitswesen gibt es Spannungsfelder, die unter anderem in verschiedenen rechtlichen Rahmenbedingungen und Handlungslogiken begründet liegen. Vor diesem Hintergrund werden Empfehlungen für die Wissenschaft, die Förderlandschaft, die Praxis sowie die Aus- und Weiterbildung formuliert.Urban planning and public health are main fields of action when looking at urban development from a health perspective. In both fields of action, politics and administration as well as urban initiatives play a formative role. Action is oriented towards common overarching themes of sustainability, social justice and environmental justice. These commonalities are reflected in different memoranda. Despite the common basis of urban planning and health, there are areas of tension that are rooted, among other things, in different legal frameworks and logic of action. Against this complex background, recommendations are formulated for science, the funding landscape, practice as well as education and training in these areas
Suitability Assessment of Different Sensors to Detect Hidden Installations for As-Built BIM
Get PDFKnowledge on the utilities hidden in the wall, e.g., electric lines or water pipes, is indispensable for work safety and valuable for planning. Since most of the existing building stock originates from the pre-digital era, no models as understood for Building Information Modeling (BIM) exist. To generate these models often labor-intensive procedures are necessary; however, recent research has dealt with the efficient generation and verification of a building’s electric network. In this context, a reliable measurement method is a necessity. In this paper we test different measurement techniques, such as point-wise measurements with hand-held devices or area-based techniques utilizing thermal imaging. For this purpose, we designed and built a simulation environment that allows various parameters to be manipulated under controlled conditions. In this scenario the low-cost handheld devices show promising results, with a precision between 92% and 100% and a recall between 89% and 100%. The expensive thermal imaging camera is also able to detect electric lines and pipes if there is enough power on the line or if the temperature of the water in the pipe and the environment’s temperature are sufficiently different. Nevertheless, while point-wise measurements can directly yield results, the thermal camera requires post-processing in specific analysis software. The results reinforce the idea of using reasoning methods in both the do-it-yourself and commercial sector, to rapidly gather information about hidden installations in a building without prior technical knowledge. This paves the way for, e.g., exploring the possibilities of an implementation and presentation in augmented reality (AR)