Data access

About: Data access is a research topic. Over the lifetime, 13141 publications have been published within this topic receiving 172859 citations. The topic is also known as: Data access.

Schema-based services for identity-based access to calendar data

Abstract: A schema-based calendar service for Internet access to per-user contact data, wherein access to data is based on each user's identity. The calendar service includes a schema that defines rules and a structure for each user's data, and also includes methods that provide access to the data in a defined way. The calendar schema thus corresponds to a logical document containing the data for each user. The user manipulates (e.g., reads or writes) data in the logical document by data access requests through defined methods. In one implementation, the calendar schemas are arranged as XML documents, and the services provide methods that control access to the data based on the requesting user's identification, defined role and scope for that role. In this way, data can be accessed by its owner, and shared to an extent determined by the owner. The structure of the data is defined from the perspective of the data, not from that of an application program or a device, whereby appropriate programs can communicate with the calendar service to access the data, with existing knowledge of the schema-defined format, regardless of the device or application program in use. Extensibility is defined into the schema.

Remote data access and integration of distributed data sources through data schema and query abstraction

Abstract: The present invention generally is directed to a system, method and article of manufacture for accessing data independent of the particular manner in which the data is physically represented. In one embodiment, a data repository abstraction layer provides a logical view of the underlying data repository that is independent of the particular manner of data representation. In one embodiment, the data repository abstraction layer specifies a location of data in a repository and a method for accessing the data. A query abstraction layer is also provided and is based on the data repository abstraction layer. A runtime component performs translation of an abstract query into a form that can be used against a particular physical data representation.

Multiple data store authentication

Abstract: System and methods for authenticating access to multiple data stores are disclosed. The system may include a server coupled to a network, a client device in communication with the server via the network and a plurality of data stores. The server may authenticate access to the data stores and forward information from those stores to the client device. An exemplary authentication method receives a request for access to data. Information concerning access to that data is stored and associated with an identifier assigned to a client device. If the identifier is found to correspond to the stored information during a future request for access to the store, access to that store is granted.

Optimal index and data allocation in multiple broadcast channels

Abstract: The issue of data broadcast has received much attention in mobile computing. A periodic broadcast of frequently requested data can reduce the workload of the up-link channel and facilitate data access for the mobile user. Since the mobile units usually have limited battery capacity, the minimization of the access latency for the broadcast data is an important problem. The indexing and scheduling techniques on the broadcast data should be considered. We propose a solution to find the optimal index and data allocation, which minimizes the access latency for any number of broadcast channels. We represent all the possible allocations as a tree in which the optimal one is searched, and propose a pruning strategy based on some properties to greatly reduce the search space. Experiments are performed to show the effectiveness of the pruning strategy. Moreover, we propose two heuristics to solve the same problem when the size of the broadcast data is large.

Index compression using 64-bit words

Abstract: Modern computers typically make use of 64-bit words as the fundamental unit of data access. However the decade-long migration from 32-bit architectures has not been reflected in compression technology, because of a widespread assumption that effective compression techniques operate in terms of bits or bytes, rather than words. Here we demonstrate that the use of 64-bit access units, especially in connection with word-bounded codes, does indeed provide the opportunity for improving the compression performance. In particular, we extend several 32-bit word-bounded coding schemes to 64-bit operation and explore their uses in information retrieval applications. Our results show that the Simple-8b approach, a 64-bit word-bounded code, is an excellent self-skipping code, and has a clear advantage over its competitors in supporting fast query evaluation when the data being compressed represents the inverted index for a large text collection. The advantages of the new code also accrue on 32-bit architectures, and for all of Boolean, ranked, and phrase queries; which means that it can be used in any situation. Copyright © 2010 John Wiley & Sons, Ltd.