1,663 research outputs found
On the Selection of Optimal Index Configuration in OO Databases
An operation in object-oriented databases gives rise to the processing of a path. Several database operations may result into the same path. The authors address the problem of optimal index configuration for a single path. As it is shown an optimal index configuration for a path can be achieved by splitting the path into subpaths and by indexing each subpath with the optimal index organization. The authors present an algorithm which is able to select an optimal index configuration for a given path. The authors consider a limited number of existing indexing techniques (simple index, inherited index, nested inherited index, multi-index, and multi-inherited index) but the principles of the algorithm remain the same adding more indexing technique
Hierarchical Role-Based Access Control with Homomorphic Encryption for Database as a Service
Database as a service provides services for accessing and managing customers
data which provides ease of access, and the cost is less for these services.
There is a possibility that the DBaaS service provider may not be trusted, and
data may be stored on untrusted server. The access control mechanism can
restrict users from unauthorized access, but in cloud environment access
control policies are more flexible. However, an attacker can gather sensitive
information for a malicious purpose by abusing the privileges as another user
and so database security is compromised. The other problems associated with the
DBaaS are to manage role hierarchy and secure session management for query
transaction in the database. In this paper, a role-based access control for the
multitenant database with role hierarchy is proposed. The query is granted with
least access privileges, and a session key is used for session management. The
proposed work protects data from privilege escalation and SQL injection. It
uses the partial homomorphic encryption (Paillier Encryption) for the
encrypting the sensitive data. If a query is to perform any operation on
sensitive data, then extra permissions are required for accessing sensitive
data. Data confidentiality and integrity are achieved using the role-based
access control with partial homomorphic encryption.Comment: 11 Pages,4 figures, Proceedings of International Conference on ICT
for Sustainable Developmen
Effect of matrix parameters on mesoporous matrix based quantum computation
We present a solid state implementation of quantum computation, which
improves previously proposed optically driven schemes. Our proposal is based on
vertical arrays of quantum dots embedded in a mesoporous material which can be
fabricated with present technology. We study the feasibility of performing
quantum computation with different mesoporous matrices. We analyse which matrix
materials ensure that each individual stack of quantum dots can be considered
isolated from the rest of the ensemble-a key requirement of our scheme. This
requirement is satisfied for all matrix materials for feasible structure
parameters and GaN/AlN based quantum dots. We also show that one dimensional
ensembles substantially improve performances, even of CdSe/CdS based quantum
dots
Mesoporous matrices for quantum computation with improved response through redundance
We present a solid state implementation of quantum computation, which improves previously proposed optically driven schemes. Our proposal is based on vertical arrays of quantum dots embedded in a mesoporous material which can be fabricated with present technology. The redundant encoding typical of the chosen hardware protects the computation against gate errors and the effects of measurement induced noise. The system parameters required for quantum computation applications are calculated for II-VI and III-V materials and found to be within the experimental range. The proposed hardware may help minimize errors due to polydispersity of dot sizes, which is at present one of the main problems in relation to quantum dot-based quantum computation. (c) 2007 American Institute of Physics
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