43 research outputs found
Long-term morphological modelling of tidal inlet systems: Implementing salt marshes in ASMITA
No full textA rise in the global mean temperature induced by climate change is expected to have a large impact on ecosystems in all regions of the world. One of the threats is accelerated sea level rise (SLR). This may induce the loss of intertidal areas in tidal inlet systems. The long-term morphological response of tidal inlet systems can be modelled using reduced complexity model ASMITA (Aggregated Scale Morphological Interaction between Tidal inlets and the Adjacent coast). The ASMITA model simulates morphological development on an aggregated spatial and temporal scale by imposing a morphological equilibrium condition. As such the model is fast, allowing for multiple long-term simulations. The model is physics-based and the parameters can be related to field values. Currently, salt marshes are not implemented in ASMITA. However, salt marshes could be of importance to the morphological development in tidal inlet systems. Moreover, it is relevant to assess the resilience of the ecologically important salt marshes by themselves. The aim of this research is to implement salt marshes in ASMITA to assess their influence on the rest of the tidal inlet system and to gain insight into the long-term morphological response of salt marshes to accelerated SLR. Salt marsh development is governed by horizontal and vertical processes. The marsh height increases by capturing mineral sediment and by the accumulation of plant biomass. Autocompaction and deep subsidence lead to a decrease in marsh height. The implementation of salt marshes in ASMITA relies solely on the input of mineral sediment. At the marsh edge, generally, a cyclic behaviour of sedimentation and cliff erosion occurs. Due to the high degree of spatial aggregation, cliff erosion is excluded from the model extension. The governing processes for salt marsh development in the ASMITA model extension are mineral sedimentation, sediment availability and relative SLR. The spatial and temporal aggregation of governing processes for salt marsh development are included in the aggregated advection-diffusion equation and model parameters for the horizontal & vertical exchange of sediment, and sediment availability. Data analysis on hydrodynamic conditions and salt marsh development was conducted for the derivation and calibration of these model parameters. To verify the salt marsh implementation, three ASMITA models were created. A one-element salt marsh model consisting of only a salt marsh element, and two different multiple elements models, which contain the ebb-tidal delta, channels, tidal flats and salt marshes. It can be concluded that ASMITA can model the mineral sedimentation on a salt marsh but depicts a large sensitivity to the parameter setting, particularly for the sediment concentration. Based on the chosen parameter configuration, the Oosterkwelder salt marsh is preserved when subjected to SLR rates below 16 mm/year. The ASMITA salt marsh extension can be employed to obtain an expeditious first impression of long-term morphological salt marsh development. However, due to the lack of incorporation of detailed processes, the model should not be employed for in-depth analyses of salt marsh development. The interaction between the salt marsh element and the remaining tidal inlet system components requires further model improvements.Civil Engineerin
#nowplaying-rs
No full text<p>The nowplaying-rs dataset features context- and content features of listening events. It contains 11.6 million music listening events of 139K users and 346K tracks collected from Twitter. The dataset comes with a rich set of item content features and user context features, as well as timestamps of the listening events. Moreover, some of the user context features imply the cultural origin of the users, and some others - like hashtags - give clues to the emotional state of a user underlying a listening event.</p>
<p>The dataset contains three files:</p>
<ul>
<li>user_track_hashtag_timestamp.csv contains basic information about each listening event. For each listening event, we provide an id, the user_id, track_id, hashtag, created_at </li>
<li>context_content_features.csv: contains all context and content features. For each listening event, we provide the id of the event, user_id, track_id, artist_id, content features regarding the track mentioned in the event (instrumentalness, liveness, speechiness, danceability, valence, loudness, tempo, acousticness, energy, mode, key) and context features regarding the listening event (coordinates (as geoJSON), place (as geoJSON), geo (as geoJSON), tweet_language, created_at, user_lang, time_zone, entities contained in the tweet).</li>
<li>sentiment_values.csv contains sentiment information for hashtags. It contains the hashtag itself and the sentiment values gathered via four different sentiment dictionaries: AFINN, Opinion Lexicon, Sentistrength Lexicon and vader. For each of these dictionaries we list the minimum, maximum, sum and average of all sentiments of the tokens of the hashtag (if available, else we list empty values). However, as most hashtags only consist of a single token, these values are equal in most cases. Please note that the lexica are rather diverse and therefore, are able to resolve very different terms against a score. Hence, the resulting csv is rather sparse. The file contains the following comma-separated values: <hashtag, vader_min, vader_max, vader_sum,vader_avg, afinn_min, afinn_max, afinn_sum, afinn_avg, ol_min, ol_max, ol_sum, ol_avg, ss_min, ss_max, ss_sum, ss_avg >, where we abbreviate all scores gathered over the Opinion Lexicon with the prefix 'ol'. Similarly, 'ss' stands for SentiStrength. </li>
</ul>
<p>Please note that user_track_hashtag_timestamp.csv and context_content_features.csv partly provide the same features. We deliberately chose to do so to be able to provide useable files that do not have to be matched and joined with each other to perform e.g., simple recommendation tasks.</p>
<p>Please also find the training and test-splits for the dataset in this repo. Also, Asmita provides prototypical implementations of a context-aware recommender system based on the dataset at https://github.com/asmitapoddar/nowplaying-RS-Music-Reco-FM.</p>
<p><br>
If you make use of this dataset, please cite the following paper where we describe and experiment with the dataset:</p>
<p>@inproceedings{smc18,<br>
title = {#nowplaying-RS: A New Benchmark Dataset for Building Context-Aware Music Recommender Systems},<br>
author = {Asmita Poddar and Eva Zangerle and Yi-Hsuan Yang},<br>
url = {http://mac.citi.sinica.edu.tw/~yang/pub/poddar18smc.pdf},<br>
year = {2018},<br>
date = {2018-07-04},<br>
booktitle = {Proceedings of the 15th Sound & Music Computing Conference},<br>
address = {Limassol, Cyprus},<br>
note = {code at https://github.com/asmitapoddar/nowplaying-RS-Music-Reco-FM},<br>
tppubtype = {inproceedings}<br>
}</p>
ASMITA modelling of the Wadden Sea with focus on the Groningerwad: Assessing how the Groningerwad will respond to accelerated sea level rise
No full textSome of the sediment which is eroded from the Dutch coast ends up in the Wadden Sea. Because of this the morphological development of the Wadden Sea is important, not only for the Wadden Sea itself but also for the maintenance programs of the adjacent coastlines. This is one of the reasons that the morphological development of the Wadden Sea is extensively studied. Some of these studies use the ASMITA model to make predictions of the morphological development with accelerating sea level rise. The Groningerwad is a part of the Wadden Sea consisting of a number of smaller tidal basins which has not been modelled with ASMITA. It has not yet been necessary to structurally nourish the coastlines surrounding the Groningerwad. However, as sea level rise increases it might well be possible that the coastal profiles surrounding the Groningerwad require nourishment. Therefore this thesis aims to study the Groningerwad with ASMITA to make a prediction of how the area will develop with accelerating sea level rise. To do this a morphological study is performed to determine the current morphological developments. This morphological study, based on available literature and bathymetry measurements of the area, finds that the Groningerwad is a highly dynamic area. It also determined the area and characterizing volume of each of the tidal basins, which have been used to set up the ASMITA model. For each basin in the Groningerwad an ASMITA model is set up using the information from the morphological study. The ASMITA model is used to make predictions for the development of the intertidal, channel and delta volumes of each of the Groningerwad its basins. The required parameters for the model have been derived from relevant formulas and the assumption that the Groningerwad is currently in a morphodynamic equilibrium. This was done because the time period for which bathymetrical measurements are available are to short to allow for a proper calibration procedure for these parameters. With this setup the ASMITA models show that all basins will lose intertidal sediment volume with rising sea levels. The larger basins of the Groningerwad also will not reach a new dynamic equilibrium state with large levels of sea level rise rate increase. When comparing these results to other basins in the Wadden Sea, it appears that the basins in the Groningerwad respond a lot slower than other Wadden Sea basins. Given the difference between the Groningerwad and the Wadden Sea and the fact that the time period over which bathymetrical data is available was to short to fully calibrate the model the recommendation is made to revisit this study when more data is available and it is possible to calibrate the relevant parameters.Civil Engineerin
Debate
No full textFMR 15 included two articles on the need to protect children from sexual exploitation and abuse in humanitarian crises. Since then, the UN has carried out its own investigation into the matter. Asmita Naik – author of one of the articles in FMR 15 – responds here to the UN’s report
Identification of Sannyasis in Paintings of Lepakshi Temple
No full textLepakshi is a small town1 situated in Hindupur taluka of Anantpur district, Andhra Pradesh. It is famous for Veerbhadra temple built during Vijaynagar empire era having monumental temple architecture. The walls and ceilings of the temple were extensively decorated with Vijaynagar style. Now some of the paintings are detoriated.
One of the mural paintings in Mahamandapa depicts Dakshinamoorti Shiv, one of the forms of Shiv. There are two sadhus in the same mural whose sects are unidentified yet. In this paper I have tried to prove that these sadhus are Dandi sannyasis of Dashnami shaiva sampradaya
Manmath Pooja
No full textLepakshi is a small town1 situated in Hindupur taluka of Anantpur district, Andhra Pradesh. Veerbhadra temple located in Lepakshi is famous for monumental temple architecture of Vijaynagar Empire period. The extensive mural paintings executed on the walls and temple ceilings are world famous. One of the painting ‘Girija Kalyanam’ depicts story of marriage of Shiv and Parvati. It is a narrative panel. It starts with the painting famously known as ‘Parvati’s toilet’. In this paper, I have tried to prove that it is not ‘Parvati’s toilet’ but ‘Manmath Pooja’
Absence of Nose Ornaments in the Paintings of Lepakshi Temple
No full textIn Andhra Pradesh, in the village of Lepakshi, there is a temple dedicated to Veerabhadra. This temple, from the Vijayanagara Empire, is located in the Hindupur taluk of the Anantapur district. The murals from the Vijayanagara Empire are a specialty of this place. If one wants to witness the amalgamation of Vijayanagara\u27s art, architecture, and temple craftsmanship in one place, then this temple is the most suitable. Here, there are many paintings and sculptures depicting various subjects. In the glorious Vijayanagara Empire, the allure of adornments is evident on all men and women, but the nose rings are nowhere to be seen. This is the subject of research undertaken in this essay
The impact of gas extraction and sea level rise on the morphology of the Wadden Sea: Extension and application of the model ASMITA
No full textIt is the policy of the Dutch government to aim at the extraction of gas from the smaller gas fields in The Netherlands to spare the large Slochteren field in Groningen. The gas reservoirs below the Wadden Sea are counted among the smaller fields. Their capacity is estimated to 200 thousand million cubic metres, and their economic value is equal to about 20 thousand million guilder. Extraction will disturb the morphologic equilibrium. At the commission of the NAM it is investigated to what extent gas extraction affects the morphology of the Wadden Sea. These effects are studied for combinations of three sea level rise scenarios and three scenarios of bottom subsidence. The sea level rise scenarios consist of the recent scenario (0.18 m/century), the expected scenario (average 0.60 m/century) and the high scenario (average 1.00 m/century). The bottom subsidence scenarios consist of no subsidence, minimum subsidence and maximum subsidence. The effects are studied for the flats, channels, deltas and adjacent coasts of the Friesche Zeegat. To study these effects, the model ASMITA is used. ASMITA is an acronym for: "Aggregated Scale Morphological Interaction between a Tidal inlet system and the Adjacent coast". ASMITA is an aggregated-scale behaviour-model of a tidal inlet system, which can be used for long-term modelling. The model consists of three major morphological elements, i.e. the tidal basin, the ebb-tidal delta and the directly adjacent coast. Each of these elements is primarily influenced by the basin-related tidal prism flow and secondarily by the by wave-related hydrodynamics. From each element the equilibrium state is known. In this equilibrium state each element has the same constant overall equilibrium concentration. Disturbance of this equilibrium (e.g. change in volume) results in an exchange of sediment between the various elements until the former equilibrium state is reached again. The exchange is mainly based on diffusion. The basic model consists of five elements: one coastal element at both sides of the delta, an ebb-tidal delta, a channel and a flat. To study the effects for the coast, the model is extended with three extra coastal elements at both sides ofthe delta. At both sides, the coast now consists of two elements which are placed at the side of the coast, and two elements which are placed seawards. The elements farther away from the inlet have a lower equilibrium concentration because the influence of the waves and/or tides is smaller. Due to the differences in equilibrium concentrations diffusive transports are generated. To create an equilibrium the net transport between the elements should equal zero. In long shore direction the diffusive transport is compensated for with a wave-generated sediment transport, which depends on the curvature of the island head and on the littoral transport. And in cross-shore direction the diffusive transport is compensated for with a slopegenerated transport. The model is also adjusted for sea level rise. As regards the coast one can distinguish two effects of sea level rise: an overall and a local effect. The overall effect comprises the structural erosion of the upstream coast due to the sand demand from the tidal basin, and the local effect comprise the "Bruun-effect" and the "island-head effect". The last effect represents the curvature of the island head due to stronger influence of the tides.Hydraulic EngineeringCivil Engineering and Geoscience
Development and extension of an aggregated scale model: Part 1 – Background to ASMITA
No full textWhilst much attention has been given to models that describe wave, tide and sediment transport processes in sufficient detail to determine the local changes in bed level over a relatively detailed representation of the bathymetry, far less attention has been given to models that consider the problem at a much larger scale (e.g. that of geomorphological elements such as a tidal flat and tidal channel). Such aggregated or lumped models tend not to represent the processes in detail but rather capture the behaviour at the scale of interest. One such model developed using the concept of an equilibrium concentration is the Aggregated Scale Morphological Interaction between Tidal basin and Adjacent coast (ASMITA). In this paper we provide some new insights into the concepts of equilibrium, and horizontal and vertical exchange that are key components of this modelling approach. In a companion paper, we summarise a range of developments that have been undertaken to extend the original model concept, to illustrate the flexibility and power of the conceptual framework. However, adding detail progressively moves the model in the direction of the more detailed process-based models and we give some consideration to the boundary between the two
Future sediment exchange between the Dutch Wadden Sea and North Sea Coast - Insights based on ASMITA modelling
No full textThe sediment exchange between the Dutch Wadden Sea and the North Sea coastal zone is of key importance to Dutch coastal management. Net sediment import from the coastal zone to the Wadden Sea results in coastal erosion which needs to be compensated through nourishments. At the same time net sediment import is the source of sediment for the intertidal flats in the Wadden Sea to adapt to sea level rise (SLR). Understanding the current and future sediment exchange is therefore essential for sustainable coastal management. Insights in the sediment exchange directly influence the coastal nourishment strategies applied to the Dutch coasts. Projections of the future sediment exchange between the Dutch Wadden Sea and the North Sea are established using the aggregated morphodynamic model ASMITA for five sea level rise scenarios, viz. the present rate of 2 mm/yr and accelerated rates of 4, 6, 8 and 17 mm/yr in 2100. The differences in the projected import rates between the five sea level rise scenarios until 2100 are not as large as the differences in sea level rise rates may suggest. For the Eastern part of the Dutch Wadden Sea, where the morphology is near its dynamic equilibrium, the projected import rate in 2100 varies with a factor 3 (300%), for sea level rise rates from 2 to 17 mm/yr (factor 8.5, 850%). In the western part of the Dutch Wadden Sea, where the morphology is still far from equilibrium due to the closure of the Zuiderzee, the projected import rate in 2100 varies a factor 1.45 (145%) for these sea level rise rates. For the total Dutch Wadden Sea this is a factor 1.7 (170%). The projected increase of the import rate until 2100 with respect to the present situation (2020) is up to a factor 1.45 (145%) for the highest sea level rise scenario, which is significant but not substantial.Coastal Engineerin
