In this paper, we consider a discrete-time queue of Geo/Geo/c type with geometric repeated attempts. It is known that its continuous counterpart, namely the M/M/c queue with exponential retrials, is analytically intractable due to the spatial heterogeneity of the underlying Markov chain, caused from the retrial feature. In discrete-time, the occurrence of multiple events at each slot increases ...

The geo-spatial database is a new technology in database systems which allow storing, retrieving and maintaining the spatial data. In this paper, we seek to design and implement a geo-spatial database for managing the traveler’s demand with the aid of open-source tools and object-relational database package. The building of geo-spatial database starts with the design of data model in terms of c...

A geo-ontology can be built around a Geographic Information System (GIS) and enriched with a firstorder logic language under the closed-world assumption (CWA). This extended system provides knowledge representation formalisms that are aimed to describe general conceptual information. They can also be used in the construction of the knowledge base of a reasoning tool. In this paper an environmen...

In this paper we propose an efficient offline job scheduling algorithm working in a grid environment that is based on a relatively new evolutionary metaheuristic called generalized extremal optimization (GEO). We compare our experimental results with those obtained using a very popular evolutionary metaheuristic, the genetic algorithm (GA). The scheduling algorithm implies two-stage scheduling....

In the hydro/solvothermally synthesized title compound, Na(4)[Cu(2)(H(2)Ge(2)O(7))(H(2)GeO(4))(2)]·H(2)O, the framework building units include CuO(4), GeO(2)(OH)(2) and GeO(3)(OH) tetra-hedra, the latter being condensed into H(2)Ge(2)O(7) (4-) dimers. All the tetra-hedra are connected by corner-sharing into four-membered-ring (4MR) secondary building units containing two CuO(4), one GeO(2)(OH)(...

Perspectives within social interaction situations are often shaped by geo-historical contexts derived from knowledge of indirectly experienceable phenomena such as geographic scale entities and past events that are communicated through external representations such as maps and historical accounts. Although geo-historical context is important for proving meaning to collaborative situations, no f...

Natural language place descriptions in everyday communication provide a rich source of spatial knowledge about places. An important step to utilize such knowledge in information systems is geo-referencing all the places referred to in these descriptions. Current techniques for geo-referencing places from text documents are using place name recognition and disambiguation; however, place descript...