Ontological considerations of time, meta-predicates and temporal propositions

A natural approach to representing and reasoning about temporal propositions (i.e., statements with time-dependent truth-values) is to associate them with time elements. In the literature, there are three choices regarding the primitive for the ontology of time: (1) instantaneous points, (2) durative intervals and (3) both points and intervals. Problems may arise when one conflates different views of temporal structure and questions whether some certain types of temporal propositions can be validly and meaningfully associated with different time elements. In this paper, we shall summarize an ontological glossary with respect to time elements, and diversify a wider range of meta-predicates for ascribing temporal propositions to time elements. Based on these, we shall also devise a versatile categorization of temporal propositions, which can subsume those representative categories proposed in the literature, including that of Vendler, of McDermott, of Allen, of Shoham, of Galton and of Terenziani and Torasso. It is demonstrated that the new categorization of propositions, together with the proposed range of meta-predicates, provides the expressive power for modeling some typical temporal terms/phenomena, such as starting-instant, stopping-instant, dividing-instant, instigation, termination and intermingling etc.

A sound and complete reified temporal logic

There are mainly two known approaches to the representation of temporal information in Computer Science: modal logic approaches (including tense logics and hybrid temporal logics) and predicate logic approaches (including temporal argument methods and reified temporal logics). On one hand, while tense logics, hybrid temporal logics and temporal argument methods enjoy formal theoretical foundations, their expressiveness has been criticised as not power enough for representing general temporal knowledge; on the other hand, although current reified temporal logics provide greater expressive power, most of them lack of complete and sound axiomatic theories. In this paper, we propose a new reified temporal logic with a clear syntax and semantics in terms of a sound and complete axiomatic formalism which retains all the expressive power of the approach of temporal reification.

Characterizing the most general temporal constraint

This paper introduces a characterization of the so-called most general temporal constraint (GTC), which guarantees the common-sense assertion that "the beginning of the effect cannot precede the beginning of the cause". The formalism is based on general time theory which takes both points and intervals as primitive. It is shown that there are in fact 8 possible causal relationships which satisfy GTC, including cases where, on the one hand, effects start simultaneously with, during, immediately after, or some time after their causes, and on the other hand, events end before, simultaneously with, or after their causes. These causal relationships are versatile enough to subsume those representatives in the literature.

Deriving explanations from partial temporal information

The representation and manipulation of natural human understanding of temporal phenomena is a fundamental field of study in Computer Science, which aims both to emulate human thinking, and to use the methods of human intelligence to underpin engineering solutions. In particular, in the domain of Artificial Intelligence, temporal knowledge may be uncertain and incomplete due to the unavailability of complete and absolute temporal information. This paper introduces an inferential framework for deriving logical explanations from partial temporal information. Based on a graphical representation which allows expression of both absolute and relative temporal knowledge in incomplete forms, the system can deliver a verdict to the question if a given set of statements is temporally consistent or not, and provide understandable logical explanation of analysis by simplified contradiction and rule based reasoning.

Property in body parts and products of the human body

An intriguing question, which until recently had not been directly explored by the courts, is the extent to which English law recognises body parts and products of the human body as property capable of ownership. Although the common law currently recognises no general property in a dead body (and only limited possessory rights in respect of it), this apparent “no-property rule” provides no justification, it is submitted, for denying proprietary status to parts or products of a living human body. The recent decision of the Court of Appeal in Yearworth v. North Bristol NHS Trust ([2009] EWCA Civ 37) lends strong support to the view that genetic material (as the product of a living human body) is capable of ownership, at least in the context of a claim in the tort of negligence and bailment. This article examines the various issues by reference to both English and Commonwealth authority.

The completeness and soundness of temporal theories

Generally speaking, the term temporal logic refers to any system of rules and symbolism for representing and reasoning about propositions qualified in terms of time. In computer science, particularly in the domain of Artificial Intelligence, there are mainly two known approaches to the representation of temporal information: modal logic approaches including tense logic and hybrid temporal logic, and predicate logic approaches including temporal arguement method and reified temporal logic. On one hand, while tense logic, hybrid temporal logic and temporal argument method enjoy formal theoretical foundations, their expressiveness has been criticised as not power enough for representing general temporal knowledge; on the other hand, although reified temporal logic provides greater expressive power, most of the current systems following the temporal reification lack of complete and sound axiomatic theories. With there observations in mind, a new reified temporal logic with clear syntax and semantics in terms of a sound and complete axiomatic formalism is introduced in this paper, which retains all the expressive power of temporal reification.

Temporal pattern recognition in video clips detection

Temporal representation and reasoning plays an important role in Data Mining and Knowledge Discovery, particularly, in mining and recognizing patterns with rich temporal information. Based on a formal characterization of time-series and state-sequences, this paper presents the computational technique and algorithm for matching state-based temporal patterns. As a case study of real-life applications, zone-defense pattern recognition in basketball games is specially examined as an illustrating example. Experimental results demonstrate that it provides a formal and comprehensive temporal ontology for research and applications in video events detection.

Antioxidant principles of Tanacetum vulgare L. aerial parts

The methanolic extract of aerial parts of Tanacetum vulgare L. (Asteraceae) and its fractions were investigated for antioxidant activity. The crude extract displayed DPPH radical scavenging effects with an EC50 value of 37 +/- 1.2 microg/mL (n=3). Activity-guided fractionations of the crude extract resulted in the isolation of three antioxidant compounds; 3,5-O-dicaffeoylquinic acid (3,5-DCQA), axillarin and luteolin. 3,5-DCQA was the major constituent with antioxidant activity (IC50 = 9.7 microM) comparable with that of the standard quercetin (IC50 = 8.8 microM). Though the isolated compounds were previously known for their antioxidant effects, this is the first report on the identification of 3,5-DCQA from Tanacetum vulgare. The displayed potent antioxidant activity of the crude extract and isolated active principles is in support of the traditional medicinal uses of the plant for disease conditions such as wound healing, rheumatic arthritis and other inflammatory conditions.

A regional chemostratigraphically-defined correlation framework for the late Triassic TAG-I Formation in Blocks 402 and 405a, Algeria

The Triassic Argilo-Gréseux Inférieur Formation (TAG-I) is one of the principal hydrocarbon reservoirs in the Berkine Basin of Algeria. Sedimentological studies have shown that it exhibits marked spatial and temporal facies variations on both a local field scale and a regional basinal scale. This variability, combined with a lack of diagnostic flora and fauna, makes regional correlation within the unit difficult. In turn, the lack of a consistent regional stratigraphic framework hampers the comparison of the various correlation schemes devised by operators in the basin. Contrasting the TAG-I in Blocks 402 and 405a exemplifies the problems encountered when attempting regionally to define a correlation framework for the interval. Between these two blocks, a distance of approximately 200 km, there are marked changes in the style of deposition from sand-dominated, proximal fluvial systems in the SW (Block 405a, MLN, MLC, KMD and MLNW fields) to a more distal, more clay-prone system in the NE (Block 402, ROD/BRSE/BSFN, SFNE and BSF fields). A chemostratigraphic study of the TAG-I in these two blocks has allowed a four-fold correlation framework to be defined, where each chemostratigraphic package has distinctive geochemical features. Chemostratigraphic Package 10, the oldest unit, lies above the Hercynian Unconformity, but beneath a geochemically identifiable hiatal surface. Chemostratigraphic Package 20 lies above the hiatal surface but is separated from the overlying packages by a mineralogical change identifiable in both claystone and sandstone geochemistry. Chemostratigraphic Packages 30 and 40 are chemically somewhat similar, but are separated by a regional event interpreted as a period of dolocrete and lacustrine development. By combining the geochemical differentiation of the units and recognition of their stratal boundaries, it is possible to define a correlation for the TAG-I between Blocks 402 and 405a. The proposed correlation between the two blocks suggests that the northern parts of Block 405a may have been occupied by a spur or subsidiary channel from the main SW–NE-trending fluvial system, resulting in one of the chemically defined packages being demonstrably absent in the MLNW, MLN, KMD and MLC fields when compared with the other areas of the study.