We consider the problem of computing the complete answer to a query when there is limited access to relations, i.e., when binding patterns require values to be specified for certain attributes in order to retrieve data from a relation. This problem is common in information-integration systems, where heterogeneous sources have diverse and limited query capabilities. A query is stable if for any ...

The most natural and perhaps most frequently used method for testing membership of an individual tuple in a conjunctive query is based on searching trees of partial solutions, or search-trees. We investigate the question of evaluating conjunctive queries with a time-bound guarantee that is measured as a function of the size of the optimal search-tree. We provide an algorithm that, given a datab...

The multiple layers of medial entorhinal cortex (mEC) contain cells that differ in selectivity, connectivity, and cellular properties. Grid cells in layer II and in the deeper layers express triangular grid patterns in the environment. The firing rate of the conjunctive cells found in layer III and below, on the other hand, show grid-by-head direction tuning. In this study, we model the differe...

We consider the problem of computing the complete answer to a query when there is limited access to relations, i.e., when binding patterns require values to be speciied for certain attributes in order to retrieve data from a relation. This problem is common in information-integration systems, where heterogeneous sources have diverse and limited query capabilities. A query is stable if for any i...

This paper distills core lessons about how researchers (scientists, engineers, planners, etc.) interested in promoting sustainable development can increase the likelihood of producing usable knowledge. We draw the lessons from both practical experience in diverse contexts around the world and from scholarly advances in understanding the relationships between science and society. Many of these l...

BACKGROUND The tourism industry which is one of the most dynamic economic activities in today's world plays a significant role in the sustainable development. Therefore, in addition to paying attention to tourism, sustainable tourism must be taken into huge account; otherwise, the environment and its health will be damaged irreparably. METHODS To determine the level of sustainability in this ...

This paper presents insights and action proposals to better harness technological innovation for sustainable development. We begin with three key insights from scholarship and practice. First, technological innovation processes do not follow a set sequence but rather emerge from complex adaptive systems involving many actors and institutions operating simultaneously from local to global scales....

Kolaitis and Vardi pointed out that constraint satisfaction and conjunctive query containment are essentially the same problem. We study the Boolean conjunctive queries under a more detailed scope, where we investigate their counting problem by means of the algebraic approach through Galois theory, taking advantage of Post’s lattice. We prove a trichotomy theorem for the generalized conjunctive...

Objectives: The Josa, which is a Korean grammatical morpheme that indicates relationship to the clause or conveys more specific meaning, an important indicator in grammar development early childhood. purpose of this study was examine Josa use spontaneous language children childhood.Methods: Fifty young aged 2;6-3;11 years participated study. participants were classified into three age groups 6-...