16,217 research outputs found
How to Price Shared Optimizations in the Cloud
Data-management-as-a-service systems are increasingly being used in
collaborative settings, where multiple users access common datasets. Cloud
providers have the choice to implement various optimizations, such as indexing
or materialized views, to accelerate queries over these datasets. Each
optimization carries a cost and may benefit multiple users. This creates a
major challenge: how to select which optimizations to perform and how to share
their cost among users. The problem is especially challenging when users are
selfish and will only report their true values for different optimizations if
doing so maximizes their utility. In this paper, we present a new approach for
selecting and pricing shared optimizations by using Mechanism Design. We first
show how to apply the Shapley Value Mechanism to the simple case of selecting
and pricing additive optimizations, assuming an offline game where all users
access the service for the same time-period. Second, we extend the approach to
online scenarios where users come and go. Finally, we consider the case of
substitutive optimizations. We show analytically that our mechanisms induce
truth- fulness and recover the optimization costs. We also show experimentally
that our mechanisms yield higher utility than the state-of-the-art approach
based on regret accumulation.Comment: VLDB201
The XII century towers, a benchmark of the Rome countryside almost cancelled. The safeguard plan by low cost uav and terrestrial DSM photogrammetry surveying and 3D Web GIS applications
âGiving a bird-fly look at the Rome countryside, throughout the Middle Age central period, it would show as if the multiple city
towers has been widely spread around the territoryâ on a radial range of maximum thirty kilometers far from the Capitol Hill center
(Carocci and Vendittelli, 2004).
This is the consequence of the phenomenon identified with the âIncasalamentoâ neologism, described in depth in the following
paper, intended as the general process of expansion of the urban society interests outside the downtown limits, started from the half
of the XII and developed through all the XIII century, slowing down and ending in the following years. From the XIX century till
today the architectural finds of this reality have raised the interest of many national and international scientists, which aimed to study
and catalog them all to create a complete framework that, cause of its extension, didnât allow yet attempting any element by element
detailed analysis. From the described situation has started our plan of intervention, we will apply integrated survey methods and
technologies of terrestrial and UAV near stereo-photogrammetry, by the use of low cost drones, more than action cameras and reflex
on extensible rods, integrated and referenced with GPS and topographic survey. In the final project we intend to produce some 3D
scaled and textured surface models of any artifact (almost two hundreds were firstly observed still standing), to singularly study the
dimensions and structure, to analyze the building materials and details and to formulate an hypothesis about any function, based even
on the position along the territory. These models, successively georeferenced, will be imported into a 2D and 3D WebGIS and
organized in layers made visible on basemaps of reference, as much as on historical maps
Introducing Access Control in Webdamlog
We survey recent work on the specification of an access control mechanism in
a collaborative environment. The work is presented in the context of the
WebdamLog language, an extension of datalog to a distributed context. We
discuss a fine-grained access control mechanism for intentional data based on
provenance as well as a control mechanism for delegation, i.e., for deploying
rules at remote peers.Comment: Proceedings of the 14th International Symposium on Database
Programming Languages (DBPL 2013), August 30, 2013, Riva del Garda, Trento,
Ital
Protocols for Integrity Constraint Checking in Federated Databases
A federated database is comprised of multiple interconnected database systems that primarily operate independently but cooperate to a certain extent. Global integrity constraints can be very useful in federated databases, but the lack of global queries, global transaction mechanisms, and global concurrency control renders traditional constraint management techniques inapplicable. This paper presents a threefold contribution to integrity constraint checking in federated databases: (1) The problem of constraint checking in a federated database environment is clearly formulated. (2) A family of protocols for constraint checking is presented. (3) The differences across protocols in the family are analyzed with respect to system requirements, properties guaranteed by the protocols, and processing and communication costs. Thus, our work yields a suite of options from which a protocol can be chosen to suit the system capabilities and integrity requirements of a particular federated database environment
Optimized Generation and Maintenance of Materialized View using Adaptive Mechanism
Data Warehouse is storage of enormous amount of data gathered from multiple data sources, which is mainly used by managers for analysis purpose. Hence to make this data available in less amount of time is essential. Using Materialize view we can have result of query in less amount of time compared to access the same from base tables. To materialize all of the views is not possible since it requires storage space and maintenance cost. So it is required to select materialized view which minimizes response time of query and cost of maintenance. In this paper, effective approach is suggested for selection and maintenance of materialize view.
DOI: 10.17762/ijritcc2321-8169.15050
Enterprise Information Integration Using a Peer to Peer Approach
The integration of enterprise information systems has unique requirements and frequently posesproblems to business partners. We discuss specific integration issues for micro-sized enterprises onthe special case of independent sales agencies and their suppliers. We argue that the enterpriseinformation systems of those independent enterprises are technically best represented by equal peers.Therefore, we have designed the Peer-To-Peer (P2P) integration architecture VIANA for theintegration of enterprise information systems. Its architecture provides materializing P2P integrationusing optimistic replication. It is applicable to inter- and intraorganizational integration scenarios. Itis accomplished by the propagation of write operations between peers. We argue that this type ofintegration can be realized with no alteration of the participating information systems
State-of-the-art on evolution and reactivity
This report starts by, in Chapter 1, outlining aspects of querying and updating resources on
the Web and on the Semantic Web, including the development of query and update languages
to be carried out within the Rewerse project.
From this outline, it becomes clear that several existing research areas and topics are of
interest for this work in Rewerse. In the remainder of this report we further present state of
the art surveys in a selection of such areas and topics. More precisely: in Chapter 2 we give
an overview of logics for reasoning about state change and updates; Chapter 3 is devoted to briefly describing existing update languages for the Web, and also for updating logic programs;
in Chapter 4 event-condition-action rules, both in the context of active database systems and
in the context of semistructured data, are surveyed; in Chapter 5 we give an overview of some relevant rule-based agents frameworks
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