Maintaining Knowledge about Temporal Intervals

Abstract

The problem of representing temporal knowledge arises ill many areas of computer science. In applications in which such knowledge is imprecise or relative, current representations based on date lines or time instants are inadequate. An interval-based temporal logic is introduced, together WiUl a computationally effective reasoning algorithm based on constraint-propagation. This system is notable in offering a delicate balance between expressive power and the efficiency of its deductive engine. A notion of reference intervals is introduced which captures the temporal hierarchy implicit in many domains, and which can be used to precisely control the amount of deduction performed automatically by the system. Examples .are provided for a data base containing historical data, a d<lta base. used for modeling processes and process interaction, and a data base for an interactive system where the present moment is continually being updated.

Mission Operations and Autonomy

“…For example, the point algebra [34], a symbolic calculus that relates in time a set of instants with qualitative constraints without necessarily ordering them, or the interval algebra [35], a symbolic calculus that relates in time a set of intervals with qualitative constraints. More recent methods have added quantitative temporal constraints based on simple temporal problems representations [36].…”

“…Conceptually, these constructs define valid schema of values allowed in timelines while linking the values of the timelines with the resource allocations. They allow the definition of Allen's like quantitative temporal relations [35] among time points and time intervals as well as constraints on the parameters of the related values (previously described in Section 6.4.2 on temporal planning).…”

Design of real-world-scene databases with mapping to virtual CG space

“…9 by using a spatiotemporal theory [11]. In limited applications (modeling or data maneuvering), the MBB can handle data at high speed, since Allens temporal intervals theory [12] with an expansion can be applied to the spatial region. However, this method cannot model fine parts of an object.…”

Temporal alignment using the incremental unit framework

“…Though somewhat indirectly, we build upon previous general work in multimodal interfaces [19] as well as [3] which defined an interval algebra for time-series overlaps (e.g., event X could take place before event Y , or they could overlap completely or partially, etc.). The evaluation explained in Section 3 is a form of late fusion, which is similar to early work in unification-based fusion [13] and fusion at the semantic level [6,21,32].…”

“…InproTK has been used in several multimodal systems and experiments [12,14,17]. 3 Data We apply one multimodal temporally aligned dialogue of the REX corpus [31] using two modalities: speech realized as AWordIUs and gaze GazeIUs where the gaze payload is an identifier of the object that was being looked at (i.e., processed raw eye tracker data; we used dialogue N2009-N01 form the corpus using the 201 OP-UT ius as speech and 2286 OP-GZE-N ius as gaze points). To examine the effectiveness of the alignment as it would perform in a realistic scenario with dynamic and variable delays, we introduce a random delay to the speech where each delay is sampled from a normal distribution (µ=300, σ 2 = 100) in milliseconds.…”