Expressiveness of Temporal Query Languages: On the Modelling of Intervals, Interval Relationships and States

Storing and retrieving time-related information are important, or even critical, tasks on many areas of Computer Science (CS) and in particular for Artificial Intelligence (AI). The expressive power of temporal databases/query languages has been studied from different perspectives, but the kind of temporal information they are able to store and retrieve is not always conveniently addressed. Here we assess a number of temporal query languages with respect to the modelling of time intervals, interval relationships and states, which can be thought of as the building blocks to represent and reason about a large and important class of historic information. To survey the facilities and issues which are particular to certain temporal query languages not only gives an idea about how useful they can be in particular contexts, but also gives an interesting insight in how these issues are, in many cases, ultimately inherent to the database paradigm. While in the area of AI declarative languages are usually the preferred choice, other areas of CS heavily rely on the extended relational paradigm. This paper, then, will be concerned with the representation of historic information in two well known temporal query languages: it Templog in the context of temporal deductive databases, and it TSQL2 in the context of temporal relational databases. We hope the results highlighted here will increase cross-fertilisation between different communities. This article can be related to recent publications drawing the attention towards the different approaches followed by the Databases and AI communities when using time-related concepts

Bipolar querying of valid-time intervals subject to uncertainty

Databases model parts of reality by containing data representing properties of real-world objects or concepts. Often, some of these properties are time-related. Thus, databases often contain data representing time-related information. However, as they may be produced by humans, such data or information may contain imperfections like uncertainties. An important purpose of databases is to allow their data to be queried, to allow access to the information these data represent. Users may do this using queries, in which they describe their preferences concerning the data they are (not) interested in. Because users may have both positive and negative such preferences, they may want to query databases in a bipolar way. Such preferences may also have a temporal nature, but, traditionally, temporal query conditions are handled specifically. In this paper, a novel technique is presented to query a valid-time relation containing uncertain valid-time data in a bipolar way, which allows the query to have a single bipolar temporal query condition

The meaning of social context: experiences of and educational outcome of participation in two different sport contexts

The original publication is available at: http://dx.doi.org/10.1080/13573320701600571Based on a general belief in society, about the good outcome of sport, this article critically examines the meaning ? that is both the personal experience of participation and the potential educational outcome ? which is derived from participation in two sport contexts under the umbrella of the Sports City Program (SCP) in Norway. With a theoretical framework based on the field theory of Bourdieu, and a qualitative methodological approach, the article indicates that there are differences within the SCP, with one pole of the SCP close to conventional sport and the other pole more distinctly different from conventional sport. In short, there are different meanings derived from pursuing different contexts of the subfield of the SCP. Different sport contexts attract different adolescents, produce different experiences and facilitate different educational opportunities. Out of the two SCP contexts investigated, the context most similar to conventional sport basis on family socialization and facilitates reproduction, while the context most distinct from conventional sport attracts other adolescents and clears the ground for self governance and an ?adolescent lifestyle?

Temporal XML

Temporal XML is a timestamped instance of an XML data model or, more literally, an XML document in which specially-interpreted timestamps are present. In general an XML data model instance is a tree or graph in which each node corresponds to an element, attribute, or value, and each edge represents the lexical nesting of the child in the parent\u2019s content. In temporal XML, a timestamp is added to some nodes or edges in the instance. The timestamp represents the lifetime of the node or edge in one or more temporal dimensions, usually valid time or transaction time. Alternatively, temporal XML is literally an XML document or data collection in which specially-interpreted timestamps, formatted in XML, are included. Such a document yields a temporal XML data model instance when parsed

Ketterien menetelmien käyttö tietovarastoinnissa

Tämän opinnäytetyön tavoitteena on selvittää, miten hyvin toimeksiantajayrityksessä hyödynnetään ketteriä menetelmiä osana tietovarastointia. Toisena tavoitteena on löytää mahdollisia kehityskohteita toimeksiantajan käyttämissä menetelmissä. Opinnäytetyön toimeksiantajayritys on ottanut ketterät menetelmät käyttöön osana tietovarastointia kuusi kuukautta ennen opinnäytetyön aloittamista. Työn teoriaosa käsittelee tietovarastointia ja keskittyy ketteristä menetelmistä Scrumviitekehykseen ja tietovarastoinnin tuomiin haasteisiin menetelmien käytössä. Teoriaosuuden lähteinä on käytetty laajasti ketteriä menetelmiä ja tietovarastointia käsitteleviä teoksia, sekä erityisesti tietovarastoinnin kannalta ketteriin menetelmiin keskittyneitä teoksia. Empiirinen osa koostui tietovarastointiprosessiin osallistumisesta kehittäjän roolissa. Tutkimuksessa toteutettiin ETL-prosessi käyttäen ketteriä menetelmiä ja kuvataan yrityksessä käytettyjä menetelmiä. Tutkimuksessa saatuja kokemuksia peilataan teoreettiseen viitekehykseen kehityskohteiden löytämiseksi. Tutkimuksen aikana toteutettiin ETL-prosessi asetetuissa aikataulutavoitteissa käyttäen ketteriä menetelmiä. Tutkimuksen pohjalta saatiin kattavasti tuloksia ketterien menetelmien sopivuudesta tietovarastointiin. Tulosten pohjalta pystyttiin esittämään toimeksiantajayritykselle kehitysideoita ja asioita, joihin tulisi kiinnittää erityisesti huomiota.The aim of this bachelor’s thesis is to find out how agile methods have been adapted to this thesis client’s data warehousing process. The second aim is to find out possible ways to improve the used agile methods. The client of the thesis has started using agile methods in the autumn of 2015. The theoretical part of the thesis introduces the concept of data warehousing and agile methods. In addition, the theoretical section of the thesis concentrates on the Scrum framework and introduces characteristics of agile data warehousing. The empirical section of this thesis is based on taking part in the client’s data warehousing process as a developer. The empirical section includes the description of the Extract – Transform – Load (ETL) process carried out with using agile methods and common description of client’s agile methods. Findings made during study are used along with the theoretical framework to find out possible areas for improvement. The ETL -process was completed successfully achieving the given goals. The case study provided good evidence about how agile methods are suitable for data warehousing projects. Several areas for improvement possibilities were came up in the client’s agile methods