| 1. |
- Cheng, Sijin, et al.
(författare)
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OPT plus : A Monotonic Alternative to OPTIONAL in SPARQL
- 2019
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Ingår i: Journal of Web Engineering. - : RIVER PUBLISHERS. - 1540-9589 .- 1544-5976. ; 18:1-3, s. 169-206
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Tidskriftsartikel (refereegranskat)abstract
- Due to the OPTIONAL operator, the core fragment of the SPARQL query language is non-monotonic. That is, some solutions of a query result can be returned to the user only after having consulted all relevant parts of the queried dataset(s). This property presents an obstacle when developing query execution approaches that aim to reduce responses times rather than the overall query execution times. Reducing the response times?i.e., returning as many solutions as early as possible? is important in particular in Web-based client-server query processing scenarios in which network latencies dominate query execution times. Such scenarios are typical in the context of integration of Web data sources where a data integration component executes queries over a decentralized federation of such data sources. In this paper we introduce an alternative operator that is similar in spirit to OPTIONAL but without causing non-monotonicity. We show fundamental properties of this operator and observe that the downside of achieving the desired monotonicity property is a potentially significant increase in query result sizes. We study the extend of this trade-off in practice.
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| 2. |
- Britto, Ricardo, et al.
(författare)
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A TAXONOMY OF WEB EFFORT PREDICTORS
- 2017
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Ingår i: Journal of Web Engineering. - : Rinton Press. - 1540-9589 .- 1544-5976. ; 16:7-8, s. 541-570
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Tidskriftsartikel (refereegranskat)abstract
- Web engineering as a field has emerged to address challenges associated with developing Web applications. It is known that the development of Web applications differs from the development of non-Web applications, especially regarding some aspects such as Web size metrics. The classification of existing Web engineering knowledge would be beneficial for both practitioners and researchers in many different ways, such as finding research gaps and supporting decision making. In the context of Web effort estimation, a taxonomy was proposed to classify the existing size metrics, and more recently a systematic literature review was conducted to identify aspects related to Web resource/effort estimation. However, there is no study that classifies Web predictors (both size metrics and cost drivers). The main objective of this study is to organize the body of knowledge on Web effort predictors by designing and using a taxonomy, aiming at supporting both research and practice in Web effort estimation. To design our taxonomy, we used a recently proposed taxonomy design method. As input, we used the results of a previously conducted systematic literature review (updated in this study), an existing taxonomy of Web size metrics and expert knowledge. We identified 165 unique Web effort predictors from a final set of 98 primary studies; they were used as one of the basis to design our hierarchical taxonomy. The taxonomy has three levels, organized into 13 categories. We demonstrated the utility of the taxonomy and body of knowledge by using examples. The proposed taxonomy can be beneficial in the following ways: i) It can help to identify research gaps and some literature of interest and ii) it can support the selection of predictors for Web effort estimation. We also intend to extend the taxonomy presented to also include effort estimation techniques and accuracy metrics.
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| 3. |
- Ihlström Eriksson, Carina, et al.
(författare)
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A Genre Perspective on Online Newspaper Front Page Design
- 2004
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Ingår i: Journal of Web Engineering. - : Rinton Press, Princeton, New Jersey. - 1540-9589. ; 3:1, s. 50-74
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Tidskriftsartikel (refereegranskat)abstract
- Taking a genre perspective on design, this article proposes eight design recommendations for online newspapers. These recommendations are based on features that mediate a specific purpose and use between publisher and audience, which we describe as genre rules in terms of purpose, form, and positioning. They are also based on genre change regarding design, and the heritage from print regarding form and shared content elements. We have a) studied genre change through a web page analysis of nine Swedish online newspapers in 2001 and 2003, using the genre concepts content, form, functionality and positioning, and b) derived genre rules through publishers and audience understanding of the genre. We have interviewed managers, designers and editors-in-chief at the nine newspapers as well as 153 members of their audience. We show that in the design process for digital documents, it is useful to have genre awareness, i.e. to be aware of the genre characteristics, the producer's design purpose and the audience recognition and response.
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