10,824 research outputs found
Ontological theory for ontological engineering: Biomedical systems information integration
Software application ontologies have the potential to become the keystone in state-of-the-art information management techniques. It is expected that these ontologies will support the sort of reasoning power required to navigate large and complex terminologies correctly and efficiently. Yet, there is one problem in particular that continues to stand in our way. As these terminological structures increase in size and complexity, and the drive to integrate them inevitably swells, it is clear that the level of consistency required for such navigation will become correspondingly difficult to maintain. While descriptive semantic representations are certainly a necessary component to any adequate ontology-based system, so long as ontology engineers rely solely on semantic information, without a sound ontological theory informing their modeling decisions, this goal will surely remain out of reach. In this paper we describe how Language and Computing nv (L&C), along with The Institute for Formal Ontology and Medical Information Sciences (IFOMIS), are working towards developing and implementing just such a theory, combining the open
software architecture of L&C’s LinkSuiteTM with the philosophical rigor of IFOMIS’s Basic Formal Ontology. In this way we aim to move beyond the more or less simple controlled vocabularies that have dominated the industry to date
Multilevel comparison of large urban systems
For the first time the systems of cities in seven countries or regions among
the largest in the world (China, India, Brazil, Europe, the Former Soviet Union
(FSU), the United States and South Africa) are made comparable through the
building of spatio-temporal standardised statistical databases. We first
explain the concept of a generic evolutionary urban unit ("city") and its
necessary adaptations to the information provided by each national statistical
system. Second, the hierarchical structure and the urban growth process are
compared at macro-scale for the seven countries with reference to Zipf's and
Gibrat's model: in agreement with an evolutionary theory of urban systems,
large similarities shape the hierarchical structure and growth processes in
BRICS countries as well as in Europe and United States, despite their positions
at different stages in the urban transition that explain some structural
peculiarities. Third, the individual trajectories of some 10,000 cities are
mapped at micro-scale following a cluster analysis of their evolution over the
last fifty years. A few common principles extracted from the evolutionary
theory of urban systems can explain the diversity of these trajectories,
including a specific pattern in their geographical repartition in the Chinese
case. We conclude that the observations at macro-level when summarized as
stylised facts can help in designing simulation models of urban systems whereas
the urban trajectories identified at micro-level are consistent enough for
constituting the basis of plausible future population projections.Comment: 14 pages, 9 figures; Pumain, Denise, et al. "Multilevel comparison of
large urban systems." Cybergeo: European Journal of Geography (2015
Efficient Management of Short-Lived Data
Motivated by the increasing prominence of loosely-coupled systems, such as
mobile and sensor networks, which are characterised by intermittent
connectivity and volatile data, we study the tagging of data with so-called
expiration times. More specifically, when data are inserted into a database,
they may be tagged with time values indicating when they expire, i.e., when
they are regarded as stale or invalid and thus are no longer considered part of
the database. In a number of applications, expiration times are known and can
be assigned at insertion time. We present data structures and algorithms for
online management of data tagged with expiration times. The algorithms are
based on fully functional, persistent treaps, which are a combination of binary
search trees with respect to a primary attribute and heaps with respect to a
secondary attribute. The primary attribute implements primary keys, and the
secondary attribute stores expiration times in a minimum heap, thus keeping a
priority queue of tuples to expire. A detailed and comprehensive experimental
study demonstrates the well-behavedness and scalability of the approach as well
as its efficiency with respect to a number of competitors.Comment: switched to TimeCenter latex styl
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Seshat: The Global History Databank
The vast amount of knowledge about past human societies has not been systematically organized and, therefore, remains inaccessible for empirically testing theories about cultural evolution and historical dynamics. For example, what evolutionary mechanisms were involved in the transition from the small-scale, uncentralized societies, in which humans lived 10,000 years ago, to the large-scale societies with an extensive division of labor, great differentials in wealth and power, and elaborate governance structures of today? Why do modern states sometimes fail to meet the basic needs of their populations? Why do economies decline, or fail to grow? In this article, we describe the structure and uses of a massive databank of historical and archaeological information, Seshat: The Global History Databank. The data that we are currently entering in Seshat will allow us and others to test theories explaining how modern societies evolved from ancestral ones, and why modern societies vary so much in their capacity to satisfy their members’ basic human needsPeer reviewedFinal Published versio
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