Automatic code compliance with multi-dimensional data fitting in a BIM context

BIM-based tools can contribute to addressing some of the challenges faced by structural engineering practitioners. A BIM-based framework for the development of components that deliver Automatic Code Compliance (ACC) is presented. The structural design problems that such components solve are categorised as simple, where ACC can be implemented directly, or complex, where more advanced approaches are needed. The mathematical process of Multi-Dimensional Data Fitting (MDDF) is introduced in order for the latter, enabling the compression of complex engineering calculations to a single equation that can be easily implemented into a BIM software engineering package. Proof-of-concept examples are given for both cases: offsite manufactured structural joists are utilised as a non-recursive example, implementing the results obtained in the manufacturer's literature; the axial capacity of metal fasteners in axially loaded timber-to-timber connections are utilised as an example of recursive problems. The MDDF analysis and the implementation in a BIM package of those problems are presented. Finally, the concept is generalised for non-structural aspects at a framework level, and the challenges, implications, and prospects of ACC in a BIM context are discussed

A composite approach to produce reference datasets for extratropical cyclone tracks: application to Mediterranean cyclones

Many cyclone detection and tracking methods (CDTMs) have been developed in the past to study the climatology of extratropical cyclones. However, all CDTMs have different approaches in defining and tracking cyclone centers. This naturally leads to cyclone track climatologies with inconsistent physical characteristics. More than that, it is typical for CDTMs to produce a non-negligible number of tracks of weak atmospheric features, which do not correspond to large-scale or mesoscale vortices and can differ significantly between CDTMs. Lack of consensus in CDTM outputs and the inclusion of significant numbers of uncertain tracks therein have long prohibited the production of a commonly accepted reference dataset of extratropical cyclone tracks. Such a dataset could allow comparable results on the analysis of storm track climatologies and could also contribute to the evaluation and improvement of CDTMs. To cover this gap, we present a new methodological approach that combines overlapping tracks from different CDTMs and produces composite tracks that concentrate the agreement of more than one CDTM. In this study we apply this methodology to the outputs of 10 well-established CDTMs which were originally applied to ERA5 reanalysis in the 42-year period of 1979-2020. We tested the sensitivity of our results to the spatiotemporal criteria that identify overlapping cyclone tracks, and for benchmarking reasons, we produced five reference datasets of subjectively tracked cyclones. Results show that climatological numbers of composite tracks are substantially lower than the ones of individual CDTMs, while benchmarking scores remain high (i.e., counting the number of subjectively tracked cyclones captured by the composite tracks). Our results show that composite tracks tend to describe more intense and longer-lasting cyclones with more distinguished early, mature and decay stages than the cyclone tracks produced by individual CDTMs. Ranking the composite tracks according to their confidence level (defined by the number of contributing CDTMs), it is shown that the higher the confidence level, the more intense and long-lasting cyclones are produced. Given the advantage of our methodology in producing cyclone tracks with physically meaningful and distinctive life stages, we propose composite tracks as reference datasets for climatological research in the Mediterranean. The Supplement provides the composite Mediterranean tracks for all confidence levels, and in the conclusion we discuss their adequate use for scientific research and applications

Assessing the coastal hazard of Medicane Ianos through ensemble modelling

On 18 September 2020, Medicane Ianos hit the western coast of Greece, resulting in flooding and severe damage at several coastal locations. In this work, we aim at evaluating its impact on sea conditions and the associated uncertainty through the use of an ensemble of numerical simulations. We applied a coupled wave–current model to an unstructured mesh, representing the whole Mediterranean Sea, with a grid resolution increasing in the Ionian Sea along the cyclone path and the landfall area. To investigate the uncertainty in modelling sea levels and waves for such an intense event, we performed an ensemble of ocean simulations using several coarse (10 km) and high-resolution (2 km) meteorological forcings from different mesoscale models. The performance of the ocean and wave models was evaluated against observations retrieved from fixed monitoring stations and satellites. All model runs emphasized the occurrence of severe sea conditions along the cyclone path and at the coast. Due to the rugged and complex coastline, extreme sea levels are localized at specific coastal sites. However, numerical results show a large spread of the simulated sea conditions for both the sea level and waves, highlighting the large uncertainty in simulating this kind of extreme event. The multi-model and multi-physics approach allows us to assess how the uncertainty propagates from meteorological to ocean variables and the subsequent coastal impact. The ensemble mean and standard deviation were combined to prove the hazard scenarios of the potential impact of such an extreme event to be used in a flood risk management plan.</p

A composite approach to produce reference datasets for extratropical cyclone tracks: application to Mediterranean cyclones

Many cyclone detection and tracking methods (CDTMs) have been developed in the past to study the climatology of extratropical cyclones. However, all CDTMs have different approaches in defining and tracking cyclone centers. This naturally leads to cyclone track climatologies with inconsistent physical characteristics. More than that, it is typical for CDTMs to produce a non-negligible number of tracks of weak atmospheric features, which do not correspond to large-scale or mesoscale vortices and can differ significantly between CDTMs. Lack of consensus in CDTM outputs and the inclusion of significant numbers of uncertain tracks therein have long prohibited the production of a commonly accepted reference dataset of extratropical cyclone tracks. Such a dataset could allow comparable results on the analysis of storm track climatologies and could also contribute to the evaluation and improvement of CDTMs. To cover this gap, we present a new methodological approach that combines overlapping tracks from different CDTMs and produces composite tracks that concentrate the agreement of more than one CDTM. In this study we apply this methodology to the outputs of 10 well-established CDTMs which were originally applied to ERA5 reanalysis in the 42-year period of 1979–2020. We tested the sensitivity of our results to the spatiotemporal criteria that identify overlapping cyclone tracks, and for benchmarking reasons, we produced five reference datasets of subjectively tracked cyclones. Results show that climatological numbers of composite tracks are substantially lower than the ones of individual CDTMs, while benchmarking scores remain high (i.e., counting the number of subjectively tracked cyclones captured by the composite tracks). Our results show that composite tracks tend to describe more intense and longer-lasting cyclones with more distinguished early, mature and decay stages than the cyclone tracks produced by individual CDTMs. Ranking the composite tracks according to their confidence level (defined by the number of contributing CDTMs), it is shown that the higher the confidence level, the more intense and long-lasting cyclones are produced. Given the advantage of our methodology in producing cyclone tracks with physically meaningful and distinctive life stages, we propose composite tracks as reference datasets for climatological research in the Mediterranean. The Supplement provides the composite Mediterranean tracks for all confidence levels, and in the conclusion we discuss their adequate use for scientific research and applications.</p

Maths & Crafts

This paper discusses the potential of the application of principles of fractal geometry in small scale design, using the design of parametric furniture as an example. It begins by summarizing the fundamental mathematical principles of fractals and the, relatively limited, application they have had so far in design. A theoretical stance is taken, viewing fractals as form-generators with significant potential. From this, the main principles of a computational design methodology are established, drawing on parallels from other design periods. As proof-of-concept, the paper presents the application of the methodology in a specific brief for the design of a piece of furniture, accompanied with images that document and illustrates the process. A parallel is established between the 21st century methodology of digital craftsmanship presented here, and the 19th century Arts & Crafts movement. Finally, the paper presents directions for further research which would allow the utilization of fractals in different design scales

Visualizing Post - Occupancy Evaluation Data: Rationale, methodology and potential of EnViz, a visualization software prototype

This paper introduces EnViz, a software prototype for the visualization of environmental data collected from post-occupancy evaluation surveys. The piece begins by introducing the rationale for the software, and why the authors believe it can be a valuable aid for environmental building design. The development methodology is described and the basic operability and interface are presented. A case study is introduced, and the results from the application of the software on the data from it are presented with accompanying images. Further results are presented, from the use of the software in workshops with undergraduate and post-graduate students, as well as researchers and professionals. Finally, future directions of the software development and the potential of the software are given

Extreme wind events in a complex maritime environment: Ways of quantification

The rising demand of energy consumption in isolated locations such as in islands leads in the expansion of on and off-shore wind farms. The optimization of the structural design of wind turbines for such applications requires a risk analysis that is made by using the definition of return periods of extreme events with respect to the lifespan of wind turbines. This work is focusing on the estimation and the analysis of extreme wind speeds by means of the corresponding return periods based on two methods: the Peaks Over Threshold and the Annual Maxima. In addition, different methodologies and tools are tested in order to achieve more accurate results. The data used for the application are both: observations (measurements from Met Stations located on Greek islands) and modeling (a 10-year model hindcast database). The sensitivity test results were used to adjust the methodologies and make 50-year extreme wind speed maps for Northeast Mediterranean (focusing on the sea and the islands). The outcome should be used as a guide for on and off-shore wind energy applications and other construction activities. © 2015 Elsevier Ltd

Low wind speed events: persistence and frequency

Over the last decades, wind energy industry has been growing with an increasing rate. This is highly relevant to the need of new wind farm site selection with certain standards such as high wind potential and accessibility. Even in windy areas, low wind speed persistence can be characterized as an extreme (non-frequent) atmospheric condition for the electricity network as it can lead to low or no energy production. The current work is focused on the estimation of the duration and the frequency of occurrence of low wind speed events using the principles of extreme value theory. The two methods used are the ‘intensity given duration’ and the ‘duration given intensity’ that lead to the same point from different perspectives. The data used is derived from a 10 year, hindcast, high-resolution database developed by the Atmospheric Modeling and Weather Forecasting Group of the University of Athens. The great potential and multinational interest concerning energy applications in the North Sea has led to its selection as a study area. The outcome of the study includes the development of intensity–duration–frequency curves as well as a comparison between the two methodologies adopted. Based on these, the largest period of no energy production for a preselected probability of occurrence is estimated for the area of interest. The results of this work could be potentially supportive for studying the regional climatology. Such information can be included in risk assessment techniques and can be applied among others for energy activities. Copyright © 2017 John Wiley &amp; Sons, Ltd. Copyright © 2017 John Wiley &amp; Sons, Ltd