6,015 research outputs found
Development of disaster resistant built environments with commonly used building materials in Sri Lanka
No full textAt present, sustainable building construction practices are actively promoted. One of
the key strategies that can enhance the degree of sustainability is creating built environments that can last a very long time when very high level of disaster resistance is achieved with commonly available building materials in a very cost effective way. These strength enhancement methods should cover multitudes of disasters like cyclones, floods and earthquake tremors.
Masonry is a very good material for carrying compressive stresses due to gravity loads consisting of self weight and live loads. However, alternative building materials such as Compressed Stabilized Earth (CSE) bricks and blocks and rammed earth can also demonstrate a behaviour comparable to conventional masonry such as burnt clay bricks and cement sand blocks.
Lateral loads are the dominant of all forces acting in a disastrous situation. Therefore,
flexural strengths of the building materials are of very importance. These lateral forces are static or dynamic in nature. In most instances, it may be possible to find equivalent quasi-static forces for dynamic forces. This means, an accurate assessment of the lateral load carrying capacity of masonry walls and also strategies available for improving the lateral load carrying capacities will be of importance.
It is shown that for experimental determination of flexural strength parallel and perpendicular to bed joints, testing of panels with low degree of pre-compression can
give reasonable results with acceptable level of scatter. This method has been used to
determine the flexural strength parameters for both conventional and alternative materials.
It is also shown that the presence of continuous tie beams at plinth level, window sill
level and lintel level can create a situation where wall panels behave almost as vertically spanning. Since tie beams cap control the deflection in lateral direction
while applying some pre-compression, it was possible to present a theoretical concept for determining the lateral load resistance with the enhancements possible with tie beams. This method relies on the compressive strength of masonry. Once this theoretical method is used with adequate partial factors of safety, a reasonable estimate of lateral load resistance can be obtained. This method can be used even with masonry having very low flexural tensile strength parallel to bed joints.
The above method has to rely on the restraint offered by the continuous tie beam. This means that the tie beam should be adequately restrained. The ideal restraint can
be the return walls that would generally occur at 3.0 - 4.0 m intervals in houses. It would also be advisable to have the tie beam extended at least 300 to 600 mm into the partition walls since it can provide better load transfer. This means that some of the plan layout may need some adjustments. Such an integrated approach could provide a house where the masonry walls are adequately tied at various levels and hence capable of transferring loads from one element to the other thus mobilizing various load resisting systems like that can be possible with shear walls.
Even a well constructed house with these disaster resistant features can still suffer if
the foundation fails. Thus, adequate soil improvements where sandy soil (s mixed with laterite soil and re-compacted in both foundation and also around the house would be essential.
Three-dimensional finite element modelling with commercial software became a reality only recently. The use of such software like SAP 2000 to identify the likely behaviour under lateral loads was presented. A similar attempt was made to obtain the influence of the nearby houses under wind conditions using ANSYS software.
With all these disaster resistant features, it would now be possible to create a robust single storey house with potential to last as long as possible. The same techniques can be adopted for multi-storey houses as well. Therefore it can be stated with confidence that the research presented in this thesis led to a development of an integrated approach for creating disaster resistant houses. Once such robust built
environments are coupled with passive techniques already successfully used for adequate indoor thermal comfort, it would be possible to have robust houses that will need very low energy for day to day operations
astromatt42/digb_sfgs: Release for 10.21203/rs.3.rs-106679/v1
No full textThis release was used to compute the results in https://doi.org/10.21203/rs.3.rs-106679/v1
For any queries please contact the corresponding author
Use of loadbearing brickwork for three storey houses in Sri Lanka
No full textFor residential buildings, brickwork out of hand moulded burnt bricks is widely used in Sri Lanka. The majority of these buildings are single storey construction. However, in recent times, two storey residential buildings have gained popularity due to advantages such as saving in land area required and the thermal comfort that can be offered on the ground floor during the day time.
When large houses are required on small blocks of land such as 6 perch in extent, three storey residential construction can be considered as an option. This also offers further advantages since both ground and first floor are now shaded. Thus, achieving a reasonable thermal comfort in a properly planned house would be easier despite the hot humid climatic conditions prevailing in Sri Lanka.
It was shown by Jayasinghe & Attalage (1999 b) that the reduction of external surface area and the roof area of a residential building is useful for reducing the external thermal gains. Reduced external thermal gains coupled with enhanced natural ventilation can be one of the possibilities for achieving a reasonable thermal comfort. It was shown by Jayasinghe & Attalage (1999 a) that Sri Lankans can be thermally comfortable even at elevated temperatures when sufficient ventilation is available.
When three storey houses are required, the structural form generally considered is reinforced concrete frames. However, load bearing brickwork can be a cost effective alternative when the residential buildings are planned with a considerable number of partition walls and with upper floors built on top of lower floor walls.
It is shown in this report with few examples that planning of such three storey houses is practically possible. Such houses can offer a number of advantages like reduced circulation space thus leading to better usage of space, bed rooms arranged around the courtyards, study rooms located at well shaded first floors etc.
When locally available hand moulded bricks are used for construction, it is possible to
obtain a characteristic compressive strength of 1.5 N/mm2 when 1:6 cement sand mortar
is used (Jayasinghe, 1988). It is also necessary to exercise certain quality controlling
measures while selecting the bricks for construction and carrying out the actual
construction.
Since the characteristic compressive strength is limited to 1.5 N/mm2, it is necessary to
use walls of sufficient thickness for load bearing walls at lower levels. It is shown that a
wall thickness of one and a half bricks is appropriate for the ground floor and one brick
for the first floor walls. The second floor wall thicknesses should be selected with the aim of minimising the self weight, hence half a brick thick walls would be appropriate for partition walls. The external walls can be one brick thick for enhanced resistance to wind induced forces and rain water penetration.
Since openings will act as a source of weakness in load bearing walls, guidelines that can
be used for the initial layout planning stage are developed. These guidelines are also
compared with those recommended for enhanced earthquake resistance, since when new concepts are introduced, the resistance to dynamic forces could be considered as
important. The measures that can be taken to prevent cracking in such three storey
buildings are also presented along with cost effective foundation improving methods.
The cost implications of using load bearing brickwork for three storey residential
buildings were determined by carrying out a cost study. It is shown that the saving in a
house of about 200 m2 of total area could be in the range of Rs 100,000/= when compared
with the corresponding reinforced concrete framed building. Such cost savings are
extremely important for middle income earners since the bank loans are often used for
financing the house construction. Thus, it is shown that three storey residential building construction with load bearing brickwork can have many advantages such as cost effectiveness, thermal comfort, saving in land area and possibility of creating a comfortable micro climate around the house.Senate Research Gran
#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>
Converter USB/RS 485
No full textThis thesis is describing problematic of realisation of converter from USB type media into the universal RS-485 bus which is mainly used for the industrial applications (author is using frequently as a device in order to enable communication between server and RFID devices). This thesis contains theoretical information, realisation of the device itself and assesment of reached targets
Converter USB/RS 485
No full textThis thesis is describing problematic of realisation of converter from USB type media into the universal RS-485 bus which is mainly used for the industrial applications (author is using frequently as a device in order to enable communication between server and RFID devices). This thesis contains theoretical information, realisation of the device itself and assesment of reached targets
Voxelwise rs-fMRI representation learning: A non-linear variational approach
No full textResting-state fMRI (rs-fMRI) has become an important imaging modality and is commonly used to study intrinsic brain networks. These networks can be obtained by decomposing rs-fMRI data into components, using independent component analysis (ICA). Recently, these ICA components have been used as inputs for neural networks to learn complex relations between the intrinsic networks of the brain and mental disorders or demographic variables. Instead of training a non-linear classifier on these linearly decomposed components, this work asks whether unsupervised representation learning can lead to linearly separable representations for multiple downstream tasks. We propose to apply non-linear representation learning to voxelwise rs-fMRI data. Learning the non-linear representations is done using two versions of a variational autoencoder (VAE). The first version is a vanilla VAE with 3D residual blocks in both its encoder and decoder. The second version is based on the identifiable VAE and uses a time-dependent prior. The models train to reconstruct the original input data from latent variables it infers. Three predictive models then evaluate the predictive power of the latent variables on an age regression, a sex classification, and a schizophrenia classification task. Each of the predictive models performs predictions for each of the three tasks. The predictive models are a support vector machine (SVM), a k-nearest neighbor (k-NN) model, and a long short-term memory (LSTM) neural network.We show that our method performs exceptionally well on the age regression and sex classification tasks without any supervision. These results imply that VAEs can model predictive variations in their latent spaces for demographic variables. The models, however, do not do well on the schizophrenia classification task, even when the models are pretrained. Despite the lower performance on the schizophrenia classification task, the overall results are encouraging and pave the way for future work on voxelwise representation learning.Electrical Engineering | Embedded SystemsBiomedical Engineerin
СРАВНИТЕЛЬНАЯ ХАРАКТЕРИСТИКА ИЗДАНИЙ РОМАННОГО ТВОРЧЕСТВА МИР ДЖАЛАЛА
No full textIn the article, the author of advanced ideas, explores published copies of novelist Mir Jalal's novels "The Resurrection Man (1936)", "The Open Book (1945)", "People of the Same Age,1948", "The New City (1951)", "Where are we going” (1957) comparative analysis. The repeated publication of the novels of the Soviet in the Soviet era or in the modern era, always proves the relevance of the talented creator. Two of the five novels of Mir Jalal, the one we talked about, have been the subject of past and the third one.In the article, the author of advanced ideas, explores published copies of novelist Mir Jalal's novels "The Resurrection Man (1936)", "The Open Book (1945)", "People of the Same Age,1948", "The New City (1951)", "Where are we going” (1957) comparative analysis. The repeated publication of the novels of the Soviet in the Soviet era or in the modern era, always proves the relevance of the talented creator. Two of the five novels of Mir Jalal, the one we talked about, have been the subject of past and the third one
The effects of cyclones, tsunami and earthquakes on built environments and strategies for reduced damage
No full textThere is a general belief that Sri Lanka is in a
disaster free zone. However, frequent cyclone warnings
and earthquake tremors over the past few decades and the
December 2004 Tsunami show that this belief may no longer
be valid for Sri Lanka. The Tsunami of 26th December 2004,
which devastated a 800 km stretch of costal area of Sri Lanka
killed more than 36,000 unwary people and displaced more
than 800,000. It was the worst ever disaster in the history of
Sri Lanka. Due to inadequate attention paid to these events in
construction practice, the damages caused are enormous both to
human life and to the built environment. There is no guarantee
that this kind of natural disaster will not happen again. They
could repeat in the future, may be with lower magnitudes or
intensity. This indicates that some kind of disaster preparedness
is of great importance today. This paper deals with few natural
disasters which could affect the built environment, and suggests
some simple and useful guidelines to improve the disaster
resistance of low rise building
Modeling a variable surface resistance (rs) for alfalfa and assessing the ASCE rs performance in the reference evapotranspiration equation
No full text2016 Fall.Includes bibliographical references.Accurate quantification of crop water requirement is necessary for proper irrigation water management. The knowledge of actual crop evapotranspiration (ETc) is important and is necessary for estimating irrigation water requirements. The most common procedure of obtaining actual crop evapotranspiration (ETc) is by first calculating the reference crop evapotranspiration (ETr) and then multiplying it with the appropriate crop coefficients (Kc). If the surface resistance (rs) of a particular crop can be modeled, then ETc can be directly calculated without using Kc. The overall objectives of this dissertation were to model surface resistance for alfalfa reference crop and to find an effective value of the surface resistance of alfalfa in the ASCE Standardized Reference ET equation. It has been found that using a single Kc curve for different climatic conditions can lead to significant error in estimating ETc. Hence it is important to find appropriate Kc for different crops for local climatic condition. Lysimeters are generally used to determine the values of Kc, as lysimetry is considered a reliable method of quantifying the ET losses from a control volume. This study found that using lysimeter ET data to obtain Kc can be problematic especially when the field is heterogeneous. In order to develop Kc for various crops, it is recommended to use some years of reliable data with uniform healthy and unstressed crop surface conditions both inside and outside the lysimeter. This study was focused on to develop a model for surface resistance (rs) of alfalfa in order to calculate alfalfa ETc in a one-step approach without the need for Kc values. Surface resistance was estimated by inverting the aerodynamic equation using ET measured from lysimeter and sensible heat flux (H) measured from large aperture scintillometer (LAS). This observed rs showed a very good correlation with leaf area index (LAI) and crop height (hc). The alfalfa rs was then modeled as a function of LAI and hc (which is referred to as rs(LAI) and rs(hc) respectively). Then these modeled rs s were incorporated into the Penman Monteith (PM) equation to estimate alfalfa hourly ET, which performed very well when compared with the measured hourly lysimeter ET. The conventional alfalfa rs, developed by Allen et al. (1989) was found to underestimate rs significantly especially when the crop height was short (less than 25 cm). It was found that ET_conventional_rs was not applicable to estimate alfalfa ET when the crop height was less than 25 cm. The modeled rs(LAI) and rs(hc) are constant throughout the day, but in reality, rs changes throughout the day. Hence hourly variable rs was also developed based on aerodynamic resistance (ra), canopy temperature (Tc) and vapor pressure deficit (VPD). It was found that PM equation incorporating the hourly variable rs improved the alfalfa ET estimation when compared with the conventional rs approach. ASCE-EWRI Standardized Reference ET for tall reference crop was found to underestimate measured ET by about 10 per cent. The equation assumes the value of rs for alfalfa as 30 s/m. When the value of rs was changed from 30 s/m to 10 s/m, the performance of the equation improved, resulting in no bias and root mean square error (RMSE) reduction from 0.08 mm/h (15.3%) to 0.06 mm/h (11.4%) in 2009 and from 0.09 mm/h (14.1%) to 0.06 mm/h (10.1%) in 2010
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