scholarly journals Sequential linked data: The state of affairs

Semantic Web ◽  
2021 ◽  
pp. 1-36
Author(s):  
Enrico Daga ◽  
Albert Meroño-Peñuela ◽  
Enrico Motta

Sequences are among the most important data structures in computer science. In the Semantic Web, however, little attention has been given to Sequential Linked Data. In previous work, we have discussed the data models that Knowledge Graphs commonly use for representing sequences and showed how these models have an impact on query performance and that this impact is invariant to triplestore implementations. However, the specific list operations that the management of Sequential Linked Data requires beyond the simple retrieval of an entire list or a range of its elements – e.g. to add or remove elements from a list –, and their impact in the various list data models, remain unclear. Covering this knowledge gap would be a significant step towards the realization of a Semantic Web list Application Programming Interface (API) that standardizes list manipulation and generalizes beyond specific data models. In order to address these challenges towards the realization of such an API, we build on our previous work in understanding the effects of various sequential data models for Knowledge Graphs, extending our benchmark and proposing a set of read-write Semantic Web list operations in SPARQL, with insert, update and delete support. To do so, we identify five classic list-based computer science sequential data structures (linked list, double linked list, stack, queue, and array), from which we derive nine atomic read-write operations for Semantic Web lists. We propose a SPARQL implementation of these operations with five typical RDF data models and compare their performance by executing them against six increasing dataset sizes and four different triplestores. In light of our results, we discuss the feasibility of our devised API and reflect on the state of affairs of Sequential Linked Data.

Author(s):  
Lech J. Janczewski ◽  
Andrew M. Colarik

The current state of the information security domain in the United States and much of the rest of the industrialized world can best be characterized as overly optimistic. The protection of computing systems and telecommunication infrastructures from unauthorized usage, manipulation, and sabotage faces serious challenges to ensure ongoing serviceability. This is especially true when we consider our growing dependence on these infrastructures. The state of affairs regarding the security aspects of these systems is even worse. Peter G. Neumann of the Computer Science Laboratory at SRI International in Menlo Park, California states:


2020 ◽  
Vol 77 (1) ◽  
pp. 93-105
Author(s):  
Junzhi Jia

PurposeThe purpose of this paper is to identify the concepts, component parts and relationships between vocabularies, linked data and knowledge graphs (KGs) from the perspectives of data and knowledge transitions.Design/methodology/approachThis paper uses conceptual analysis methods. This study focuses on distinguishing concepts and analyzing composition and intercorrelations to explore data and knowledge transitions.FindingsVocabularies are the cornerstone for accurately building understanding of the meaning of data. Vocabularies provide for a data-sharing model and play an important role in supporting the semantic expression of linked data and defining the schema layer; they are also used for entity recognition, alignment and linkage for KGs. KGs, which consist of a schema layer and a data layer, are presented as cubes that organically combine vocabularies, linked data and big data.Originality/valueThis paper first describes the composition of vocabularies, linked data and KGs. More importantly, this paper innovatively analyzes and summarizes the interrelatedness of these factors, which comes from frequent interactions between data and knowledge. The three factors empower each other and can ultimately empower the Semantic Web.


2021 ◽  
Author(s):  
Gillian Byrne ◽  
Lisa Goddard

Semantic Web technologies have immense potential to transform the Internet into a distributed reasoning machine that will not only execute extremely precise searches, but will also have the ability to analyze the data it finds to create new knowledge. This paper examines the state of Semantic Web (also known as Linked Data) tools and infrastructure to determine whether semantic technologies are sufficiently mature for non–expert use, and to identify some of the obstacles to global Linked Data implementation.


Author(s):  
Andra Waagmeester ◽  
Paul Braun ◽  
Manoj Karingamadathil ◽  
Jose Emilio Labra Gayo ◽  
Siobhan Leachman ◽  
...  

Moths form a diverse group of species that are predominantly active at night. They are colourful, have an ecological role, but are less well described compared to their closest relatives, the butterflies. Much remains to be understood about moths, which is shown by the many issues within their taxonomy, including being a paraphyletic group and the inability to clearly distinguish them from butterflies (Fig. 1). We present the Wikimedia architecture as a hub of knowledge on moths. This ecosystem consists of 312 language editions of Wikipedia and sister projects such as Wikimedia commons (a multimedia repository), and Wikidata (a public knowledge graph). Through Wikidata, external data repositories can be integrated into this knowledge landscape on moths. Wikidata contains links to (open) data repositories on biodiversity like iNaturalist, Global Biodiversity Information Facility (GBIF) and the Biodiversity Heritage Library (BHL) which in return contain detailed content like species occurrence data, images or publications on moths. We present a workflow that integrates crowd-sourced information and images from iNaturalist, with content from GBIF and BHL into the different language editions of Wikipedia. The Wikipedia articles in turn feed information to other sources. Taxon pages on iNaturalist, for example, have an "About" tab, which is fed by the Wikipedia article describing the respective taxon, where the current language of the (iNaturalist) interface fetches the appropriate language version from Wikipedia. This is a nice example of data reuse, which is one of the pillars of FAIR (Findable, Accessible, Interoperable and Reusable) (Wilkinson et al. 2016). Wikidata provides the linked data hub in this flow of knowledge. Since Wikidata is available in RDF, it aligns well with the data model of the semantic web. This allows rapid integration with other linked data sources, and provides an intuitive portal for non-linked data to be integrated as linked data with this semantic web. rapid integration with other linked data sources, and provides an intuitive portal for non-linked data to be integrated as linked data with this semantic web. Wikidata is includes information on all sorts of things (e.g., people, species, locations, events). Which is why it can structure data in a multitude of ways, thus leading to 9000+ properties. Because all those different domains and communities use the same source for different things it is important to have good structure and documentation for a specific topic so we and others can interpret the data. We present a schema that describes data about moth taxa on Wikidata. Since 2019, Wikidata has an EntitySchema namespace that allows contributors to specify applicable linked-data schemas. The schemas are expressed using Shape Expressions (ShEx) (Thornton et al. 2019), which is a formal modelling language for RDF, one of the data formats used on the Semantic Web. Since Wikidata is also rendered as RDF, it is possible to use ShEx to describe data models and user expectations in Wikidata (Waagmeester et al. 2021). These schemas can then be used to verify if a subset of Wikidata conforms to an expected or described data model. Starting from a document that describes an expected schema on moths, we have developed an EntitySchema (E321) for moths in Wikidata. This schema provides unambiguous guidance for contributors who have data they are not sure how to model. For example, a user with data about a particular species of moth may be working from a scientific article that states that the species is only found in New Zealand, and may be unsure of how to model that fact as a statement in Wikidata. After consulting Schema E321, the user will find out about Property P183 “endemic_to” and then use that property to state that the species is endemic to New Zealand. As more contributors follow the data model expressed in schema E321, there will be structural consistency across items for moths in Wikidata. This reduces the risk of contributors using different combinations of properties and qualifiers to express the same meaning. If a contributor needs to express something that is not yet represented in Schema E321 they can extend the schema itself, as each schema can be edited. The multilingual affordances of the Wikidata platform allow users to edit in over 300 languages. In this way, contributors edit in their preferred language and see the structure of the data as well as the schemas in their language of choice. This broadens the range of people who can contribute to these data models and reduces the dominance of English. There are approximately 160K+ estimated moth species. This number is equal to the number of moths described in iNaturalist, while Wikidata contains 220K items on moths. As the biggest language edition, the English Wikipedia contains 65K moth articles; other language editions contain far fewer Wikipedia articles. The higher number of items on moths in Wikidata can be partly explained by Wikidata taxon synonyms being treated as distinct taxa. Wikidata, as a proxy of knowledge on moths, is instrumental in getting them better described in Wikipedia and other (FAIR) sources. While in return, curation in Wikidata happens by a large community. This approach to data modelling has the advantage of allowing multilingual collaboration and iterative extension and improvement over time.


2021 ◽  
Author(s):  
Gillian Byrne ◽  
Lisa Goddard

Semantic Web technologies have immense potential to transform the Internet into a distributed reasoning machine that will not only execute extremely precise searches, but will also have the ability to analyze the data it finds to create new knowledge. This paper examines the state of Semantic Web (also known as Linked Data) tools and infrastructure to determine whether semantic technologies are sufficiently mature for non–expert use, and to identify some of the obstacles to global Linked Data implementation.


2019 ◽  
Vol 57 (5) ◽  
pp. 261-277
Author(s):  
Hyoungjoo Park ◽  
Margaret Kipp
Keyword(s):  

Author(s):  
JIGAR JAIN ◽  
Rushikesh Gaidhani ◽  
Pranjal Bahuguna

Non-blocking transactional structures are now been there for quite a while now. With the transactional structure we want to achieve atomicity of multiple operation of a transaction and consistency of the structure after rollback. Older solutions like software transactional memory (STM) and transactional boost provide synchronization at an external layer over the structure itself. This introduces an overhead which is not necessarily required. Thus, it is a probable problem. To solve this issue, researchers provided with a solution which make structural changes in the existing data structure and make it transactional, lock-free. In this work we present a sequential re-implantation of a the above provided solution. We applied transactional transformation to a linked-list and made a sequential version of it. Next, we introduced multi-resource lock version of the same which will used locking to support multi- thread operation on the linked list. As anyone would expect, we get constant time graph for a sequential version of the transactional structure. But the case for locked based multi thread version is different. We get worse performance as compared to sequential version as we get the overhead of maintain a resource vector. As the number of threads increase the size of resource vector increase and thus contention increases. In future we plan to completely re-implement a lock free transactional linked data structure and yet again compare its result with the results from this paper.


2011 ◽  
Vol 59 (2) ◽  
pp. 523-556 ◽  
Author(s):  
Bernhard Schandl ◽  
Bernhard Haslhofer ◽  
Tobias Bürger ◽  
Andreas Langegger ◽  
Wolfgang Halb

Sign in / Sign up

Export Citation Format

Share Document