Event notification services are used in various applications such as digital
libraries, stock tickers, traffic control, or facility management. However to
our knowledge, a common semantics of events in event notification services has
not been defined so far. We propose a parameterized event algebra which
describes the semantics of composite events for event notification systems. The
parameters ser... hiện toàn bộ
#Algebra #Logistics #Temperature sensors #Software libraries #Filtering #Database systems #Clocks
Chúng tôi giới thiệu một logic thời gian để lý luận về các ứng dụng toàn cầu.
Trước tiên, chúng tôi định nghĩa một logic mô-đun cho địa phương tính, nhúng các
lý thuyết địa phương của mỗi thành phần vào một lý thuyết về các trạng thái phân
tán của hệ thống. Chúng tôi cung cấp cho logic một hệ thống tiên đề đầy đủ và
chuyên sâu. Sau đó, chúng tôi mở rộng logic với một toán tử thời gian. Đóng góp
củ... hiện toàn bộ
#Logic #DSL #Đồng hồ #Giao tiếp bất đồng bộ #Ngôn ngữ đặc tả #Điện toán đồng thời #Điện toán phân tán #Trì hoãn #Điện toán phổ biến #Thư viện thời gian chạy
We evaluate a model for temporal data utilizing the benefits of
object-relational database systems (ORDBS). In particular we show how attribute
timestamping can be efficiently implemented in state-of-the-art ORDBS. The
attribute timestamping concept is based on introducing user-specific types for
temporal versions of datatypes. Moreover on the physical level we make use of
user-defined index struc... hiện toàn bộ
#Object oriented modeling #Indexing #Spatial indexes #Relational databases #Information systems #Database systems #Data models #Spatial databases #Size measurement
We show the expressiveness provided by a labelled point-based metric model for
specifying and reasoning about complex disjunctive temporal constraints. The
model allows us to manage disjunctive assertions, conjunctive and hypothetical
queries, and one-to-many constraints. Additionally, it becomes an adequate
support for reasoning on costs associated to constraints.
Many natural languages use prepositions to mark relations between entities of
various kinds-between physical entities and their spatial locations, between
temporal entities and their temporal locations, between abstract entities of
various kinds (e.g. between ideas and their 'mental locations'). I show that the
consequences of using prepositions to relate temporal entities emerge naturally
from th... hiện toàn bộ
S. Bauer, I. Hodkinson, F. Wolter, M. Zakharyaschev
We prove decidability of 'non local' propositional CTL*, where truth values of
atoms may depend on the branch of evaluation. This result is then used to show
decidability of the 'weak' one-variable fragment of first-order (local) CTL*, in
which all temporal operators and path quantifiers except 'tomorrow' are
applicable only to sentences. Various spatio-temporal logics based on
combinations of CTL... hiện toàn bộ
Events employed in natural language semantics are characterized in terms of
regular languages, each string in which can be regarded as a motion picture. The
relevant finite automata then amount to movie cameras/projectors, or more
formally, to finite Kripke structures with partial valuations. The usual regular
constructs (concatenation, choice, etc) are supplemented with superposition of
strings/a... hiện toàn bộ
Temporal joins are important but very costly operations. While a temporal join
can involve the whole time (and/or key) domain, we consider the more general
case where the join is defined by some time-key rectangle from the whole space
(i.e., when the user is interested in joining portions of the-usually
large-temporal data). In the most restrictive join, objects (within this
rectangle) are joined ... hiện toàn bộ
We present a method for formalising the behaviour of simple deterministic
devices and protocols in a way that makes explicit the causal dependencies
amongst the component elements, thereby allowing true causal (as opposed to
purely temporal) reasoning. Our intention is to handle such systems effectively
in the simplest possible way, without invoking additional problematic
considerations (concernin... hiện toàn bộ