One of the central tasks in developing information systems is the specification
of desired system properties. We use the object specification language TROLL
light to formalize the conceptual model of a system. A TROLL light specification
describes structural as well as dynamic characteristics of objects representing
real world entities. For validating specifications, we have developed an
animation... hiện toàn bộ
#Animation #Object oriented modeling #Information systems #Prototypes #Specification languages #System testing #Formal specifications #Design engineering #Data models #Security
Ripple down rules (RDR) is an incremental knowledge acquisition (KA)
methodology, where a knowledge base (KB) is constructed as a collection of rules
with exceptions. Nested ripple down rules (NRDR) is an extension of this
methodology which allows the expert to enter her/his own domain concepts and
later refine these concepts hierarchically. In this paper we show similarities
between incremental k... hiện toàn bộ
#Knowledge acquisition #Object oriented databases #Spatial databases #Database systems #Knowledge based systems #Data engineering #Knowledge engineering
A new quality of service (QoS) aware disk scheduling algorithm is presented. It
is applicable in environments where data requests arrive with different QoS
requirements such as real-time deadline, and user priority. Previous work on
disk scheduling has focused on optimizing the seek times and/or meeting the
real-time deadlines. A unified framework for QoS disk scheduling is presented
that scales w... hiện toàn bộ
#Quality of service #Scheduling algorithm #Sorting #Streaming media #Bandwidth #Engine cylinders #Computer networks #Intelligent networks #Laboratories #Scalability
Boolean expression simplification is a well-known problem in the history of
computer science. The problem of determining prime implicates from an arbitrary
Boolean expression has been mostly studied in the contexts of hardware design
and automated reasoning. While many of the same principles can be applied to the
simplification of search conditions in ANSI SQL queries, the richness of its
language... hiện toàn bộ
R. Benetis, C.S. Jensen, G. Karciauskas, S. Saltenis
With the proliferation of wireless communications and the rapid advances in
technologies for tracking the positions of continuously moving objects,
algorithms for efficiently answering queries about large numbers of moving
objects increasingly are needed. One such query is the reverse nearest neighbor
(RNN) query that returns the objects that have a query object as their closest
object. While algo... hiện toàn bộ
#Nearest neighbor searches #Recurrent neural networks #Databases #Neural networks #Internet #Computer science #Wireless communication #Proposals #Home appliances #Computer industry
This paper presents a multidimensional conceptual object-oriented model, its
structures, integrity constraints and query operations. It has been developed as
an extension of UML core metaclasses to facilitate its usage, as well as to
avoid the introduction of completely new concepts. YAM/sup 2/ allows the
representation of several semantically related star schemas, as well as
summarizability and i... hiện toàn bộ
#Multidimensional systems #Unified modeling language #Solid modeling #Power system modeling #Data structures #Data models #Data analysis #Power measurement #Databases #Data engineering
A system has been developed permitting database queries over data extracted from
a CAD system where the query result is returned back to the CAD for
visualization and analysis. This has several challenges. First, CAD data
representations use complex object-oriented schemas and the query language must
be object-oriented too. Second, the query system resides outside the CAD system
and must therefore... hiện toàn bộ
Energy saving is the most important issue in wireless mobile computing due to
power constraints on mobile units. Data broadcasting is the main method of
information dissemination in wireless networks as its cost is independent of the
number of mobile hosts receiving the information. A number of data broadcasting
techniques have been proposed for mobile wireless networks, where servers have
no ener... hiện toàn bộ
#Energy efficiency #Broadcasting #Intelligent networks #Ad hoc networks #Network servers #Mobile computing #Mobile ad hoc networks #Base stations #Wireless networks #Databases
Security issues in multidatabases are complicated due to autonomy and
heterogeneity of local databases. Deriving global authorizations by integrating
underlying local authorizations is difficult since subjects and objects at each
local database may not be compatible. In addition, local authorizations may
conflict and could not be combined to form common global authorizations. This
paper proposes a... hiện toàn bộ