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Order-sensitive View Maintenance of Materialized XQuery Views
No full textMaterialized XML views are a popular technique for integrating data from possibly distributed and heterogeneous data sources. However, the problem of the incremental maintenance of such XML views poses new challenges which to date remain unaddressed. One, XML views not only filter the data, but may radically restructure it to construct new XML nested document structures. Moreover, order is inherent in the XML model, and XML views reflect both the implicit document order of the underlying sources and the order explicitly imposed in the view definition. Therefore, order also has to be preserved at view maintenance time.
In this thesis we present an algebraic approach for the incremental maintenance of XQuery views, called VOX (View maintenance for Ordered XML). To the best of our knowledge, this is the first solution to order-preserving XML view maintenance. Our strategy correctly transforms an update to source XML data into sequences of updates that refresh the view. Our technique is based on an algebraic representation of the XQuery view expression using an XML algebra. The XML algebra has ordered bag semantics; hence most of the operators logically are order preserving. We propose an order-encoding mechanism that migrates the XML algebra to (non-ordered) bag semantics, no longer requiring most of the operators to be order-aware. Furthermore, this now allows most of the algebra operators to become distributive over update operations. This transformation brings the problem of maintaining XML views one step closer to the problem of maintaining views in other (unordered) data models. We are thus now able to adopt some of the existing (relational) maintenance techniques towards our goal of efficient order-sensitive XQuery view maintenance. In addition we develop a full set of rules for propagating updates through XML specific operations. We have proven the correctness of the VOX view maintenance approach. A full implementation of VOX on top of RAINBOW, the XML data management system developed at WPI, has been completed. Our experimental results performed using the data and queries provided by the XMark benchmark, confirm that incremental XML view maintenance indeed is significantly faster than complete recomputation in most cases. Incremental maintenance is shown to outperform recomputation even for large updates
What a Difference Context Makes: Comparing Communication Strategies of Migration NGOs in Two Neighboring Countries
Get PDFThis research study compared non-governmental organizations (NGOs) working in the area of migration in two neighboring countries – Bulgaria and Turkey. Utilizing in-depth interviews with 39 NGO professionals in both countries, the analysis identified critical differences in public opinion dynamics, organizational structures and interdependencies, and government relationships. Further analysis unveiled how the local socio-economic and political context had impacted NGO communication strategies as well as the specific communication channels, public engagement activities, and social media campaigns in each country. Implications for communication scholarship during times of increasing migration flows and globalization are discussed.This article is published as Dimitrova, D., Ozdora-Aksak, E., What a Difference Context Makes: Comparing Communication Strategies of Migration NGOs in Two Neighboring Countries. Journal of Borderlands Studies. 31 Dec 2022. Latest Articles. https://doi.org/10.1080/08865655.2022.2161065. Posted with permission. © 2023 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group
This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives License (http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited, and is not altered, transformed, or built upon in any way.<br
The role of value references in shaping cultures of engagement: evidence from COVID-19 news on Facebook in Romania and the U.K.
Get PDFValues are consequential for opinion formation and remain a persuasive factor in shaping public attitudes. Still, the role of values remains under-researched in the context of online news production and engagement. This study investigates the intricate role values play by analyzing patterns of value references in online news coverage of coronavirus disease 2019 (COVID-19) in two culturally distinct nations, Romania and the U.K. Conceptually, the study is based on Schwartz’s value typology; methodologically, it relies on the Concept Mover’s Distance method. Analyzing half a million Facebook posts, the study identifies four types of value references: universal, cultural, topic-based, and situational. We show that cultural values prevalent in British posts, such as stimulation and tradition, resonate with the culturally congruent context. Universal values, however, do not guarantee a high level of engagement. The findings underscore the nuanced impact of values in shaping online news engagement.This article is published as Cristina Monzer, Daniela V Dimitrova, The role of value references in shaping cultures of engagement: evidence from COVID-19 news on Facebook in Romania and the U.K., Human Communication Research, Volume 51, Issue 1, January 2025, Pages 40–51, https://doi.org/10.1093/hcr/hqae021.© The Author(s) 2024. Published by Oxford University Press on behalf of International Communication Association.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.Supplementary material is available online at Human Communication Research online
Multimodal Interface for DNA Alignment of Sequences
No full textMajor research efforts in Bioinformatics include sequence alignment, gene finding, genome assembly, protein structure alignment, protein structure prediction, prediction of gene expression and protein-protein interactions, and the modeling of evolution. To perform these specific tasks different tools are used. Using these tools separately is a time consuming, inefficient and expensive process. MIDAS is a tool that integrates sequence alignment, genome annotation, and spectral clustering and alignment under the same application. The challenge in this project is in representing the knowledge and analyzing the genome data. The DNA data is first transformed into Fourier domain and clustered in MATLAB based on Euclidean distances between the sequences. Our tool allows visualizing the DNA spectra together with a hierarchical tree in a multimodal interface. This in turn enables a bioinformatician to analyze patterns of a group of sequences. MIDAS is a standalone application which provides an interface around standard sequence alignment tools such as BLAT, ClustalW, as well as newer alignment tools such as Spectrogram analysis via integrating MATLAB code, server connections and data visualizations. JAVA is used as the main programming language during the development of MIDAS. The Spectrogram Analysis script-files in MATLAB are converted into JAVA classes. These classes are used to run standalone MATLAB applications from within JAVA.Media and Knowledge EngineeringElectrical Engineering, Mathematics and Computer Scienc
LAG 2.0 : refining a reusable adaptation language and improving on its authoring
No full textReusable adaptation specifications for adaptive behaviour has come to the forefront of adaptive research recently, with EU projects such as GRAPPLE, and PhD research efforts on designing an adaptation language for learning style specification [28]. However, this was not the case five years ago, when an adaptation language for adaptive hypermedia (LAG) was first proposed. This paper describes the general lessons learnt during the last five years in designing, implementing and using an adaptation language, as well as the changes that the language has undergone in order to better fulfil its goal of combining a high level of semantics with simplicity, portability as well as being flexible. Besides discussing these changes based on some sample strategies, this paper also presents a novel authoring environment for the programming-savvy adaptation author, that applies feedback accumulated during various evaluation sessions with the previous set of tools, and its first evaluation with programming experts
Next-generation wind turbine tower modeling: Uncertainty quantification
No full textThe natural frequency of wind turbine towers can be more than 10% off from the designed frequency. This frequency is important for control because it sets bandwidth limits to some of the control loops. Improving the model will result in better control and load reduction that will in turn contribute to the decrease of the cost of wind energy. The main focus of this project is on uncertainty quantification. Finding more accurate uncertainty quantification techniques will help determining the accuracy of models. Currently, the accuracy of the models is described based on asymptotic statistics theory. However, asymptotic uncertainty descriptions exhibit some problems. Variance results are not reliable for small numbers of measurement samples. Moreover, the true values of the parameters are present in the asymptotic variance expressions. As a result, the uncertainty of the model is often approximately quantified or unknown. When the uncertainty of the model is not known or approximately quantified the controllers have to be designed with conservative margins. Therefore, obtaining more reliable uncertainty descriptions will enable the use of less conservative margins, and thus more aggressive controllers. For this purpose, the bootstrap technique for accuracy quantification of model estimates is proposed. Additionally, Operational Modal Analysis (OMA) is used to obtain an estimate of the natural frequency of the tower. With OMA a model of a system is identified based on the output data collected when the system is in operating conditions. The use of OMA eliminates the need to artificially excite the wind turbine tower by using artificial exciters. Another advantage of OMA over system identification approaches is that the input signal to the system is not measured and only the output vibration response of the tower is measured. In this project, the system identification method optimized Predictor Based System Identification (PBSIDopt) was adapted to work with output only data. The identification procedure was tested on a simulation example and the results showed that the proposed identification based on ambient excitation was effective. Asymptotic variance expressions for the uncertainty of the natural frequencies and damping ratios have been derived for the OMA-PBSIDopt. The uncertainty of the natural frequency and damping ratio of the identified system model has been quantified using both the asymptotic statistics and bootstrap techniques and a comparison of the results is made. It is shown that the bootstrap method outperforms the asymptotic variance approach in the sense that the bootstrap estimates of the accuracy are less sensitive to the number of measurements samples. In addition to that, unlike the asymptotic variance technique the bootstrap method is straightforward to apply.Systems and ControlDelft Center for Systems and ControlMechanical, Maritime and Materials Engineerin
Learning Object Metadata Workflows for Description, Findability and Reusability Improvement
No full textWith the increase of online education, a good description of learning resources has become vital for educational resource sharing and reuse. Resource description has been under the spotlight in recent years. Educational platforms can benefit from good resource organisation and description, thereby providing a higher quality of services and attracting more learners to use their systems. Furthermore, well-described resources with metadata, promote content sharing and re-use. This work starts with an extensive literature research on metadata generation techniques and breaks the findings down to metadata types. A detailed taxonomy of metadata types, based on this research, is provided. The taxonomy takes into account properties common to these types. Second, this work analyzes the state-of-the-art metadata collection techniques in literature and real-world educational content repositories including a showcase with the TUDelft library, in order to estimate the gap of metadata employment in the field of education. Following the results of this research and based on the observation that similar steps are often performed together, a set of easy-to-follow and generic enough design patters for generating metadata was identified. These design patterns aim at assisting content authors or data professionals with filling in metadata and thereafter, allowing for feature development or improvement in the respective platforms. The patterns for metadata extraction are based on the identified taxonomy of metadata. Finally, semantic metadata is extracted as proof of concept for two of the proposed patterns. A satisfactory to a high-quality result was achieved, showing that the patterns are intuitive and the data extracted with them, can be potentially used to describe the respective Educational Resource (ER) by adding the extracted information to its metadata.Computer Science | Web Information System
Ecologie & Esthetiek
No full textIn recent decades, the field of architecture has witnessed a fundamental shift under the banner of ‘ecology’: from the innovation in energy technologies to the use of circular materials and climate-neutral building solutions – today, more than ever, the construction of a building seems to be dominated by an ecological awareness. At the same time, such sustainable thinking often places ecological questions outside of the design itself, in the hands of experts and within the logic of quantitative calculation, while the building disappears into the ephemerality of life cycles and network models.By focusing on the intersection between ecology and aesthetics in architecture, however, this issue of OASE situates the thinking about such issues at the heart of the discipline. It asks: how do ecological questions materialise in architecture? And what aesthetic practices are able to shape the perception of these ecological questions? Through a series of concrete projects, the contributions in this issue explore the field of tension between architectural aesthetics and issues of energy, technology and materiality. Ecological practices in architecture must not only be effective in providing solutions, but inevitably raise questions of beauty, affection and perception as well.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Situated Architectur
CaptureBias: Supporting Media Scholars with Ambiguity-Aware Bias Representation for News Videos
No full textIn this project we explore the presence of ambiguity in textual and visual media and its influence on accurately understanding andcapturing bias in news. We study this topic in the context of supportingmedia scholars and social scientists in their media analysis. Our focuslies on racial and gender bias as well as framing and the comparisonof their manifestation across modalities, cultures and languages. In thispaper we lay out a human in the loop approach to investigate the role ofambiguity in detection and interpretation of bias.Accepted Author ManuscriptWeb Information System
Figure 9. The impossible figure (right) is not noticeable as such at first glance-Gestalt Processing in Human-Robot Interaction: A Novel Account for Autism Research
No full textIn the lexical domain a similar effect of holistic word processing is described in (Anstis,
2005b). The viewers were presented with pairs of three-letter words in quick succession and asked
to report if the upper halves of the successively presented words were identical. Surprisingly, even
when the upper halves of the words were orthographically identical, the error rate was reliably
higher than expected and in comparison with matching identical successive words. As the author of
the study Stuart Anstis points out: “students were processing the words not as separable parts, but
holistically as perceptual units that could not be perceptually split apart. These results show that in
normal circumstances, the visual system cannot, or does not, divide words into upper and lower
halves” (Anstis, 2005b, p. 239).The author relates the results of his study to studies of visual
perception of faces as evidence that the mechanism of holistic processing in the visual and the
lexical domains is essentially the same.https://www.edusoft.ro/brain/index.php/brain/issue/view/3
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