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.

Aggregation framework system architecture and method

Abstract: Database systems and methods that implement a data aggregation framework are provided. The framework can be configured to optimize aggregate operations over non-relational distributed databases, including, for example, data access, data retrieval, data writes, indexing, etc. Various embodiments are configured to aggregate multiple operations and/or commands, where the results (e.g., database documents and computations) captured from the distributed database are transformed as they pass through an aggregation operation. The aggregation operation can be defined as a pipeline which enables the results from a first operation to be redirected into the input of a subsequent operation, which output can be redirected into further subsequent operations. Computations may also be executed at each stage of the pipeline, where each result at each stage can be evaluated by the computation to return a result. Execution of the pipeline can be optimized based on data dependencies and re-ordering of the pipeline operations.

Supporting Cooperative Caching in Disruption Tolerant Networks

Abstract: Disruption Tolerant Networks (DTNs) are characterized by the low node density, unpredictable node mobility and lack of global network information. Most of current research efforts in DTNs focus on data forwarding, but only limited work has been done on providing effective data access to mobile users. In this paper, we propose a novel approach to support cooperative caching in DTNs, which enables the sharing and coordination of cached data among multiple nodes and reduces data access delay. Our basic idea is to intentionally cache data at a set of Network Central Locations (NCLs), which can be easily accessed by other nodes in the network. We propose an effective scheme which ensures appropriate NCL selection based on a probabilistic selection metric, and coordinate multiple caching nodes to optimize trade off between data accessibility and caching overhead. Extensive trace-driven simulations show that our scheme significantly improves data access performance compared to existing schemes.

Moving Objects Information Management: The Database Challenge

Abstract: Miniaturization of computing devices, and advances in wireless communication and sensor technology are some of the forces that are propagating computing from the stationary desktop to the mobile outdoors. Some important classes of new applications that will be enabled by this revolutionary development include location-based services, tourist services, mobile electronic commerce, and digital battlefield. Some existing application classes that will benefit from the development include transportation and air traffic control, weather forecasting, emergency response, mobile resource management, and mobile workforce. Location management, i.e. the management of transient location information, is an enabling technology for all these applications. Location management is also a fundamental component of other technologies such as fly-through visualization, context awareness, augmented reality, cellular communication, and dynamic resource discovery.In this paper we present our view of the important research issues in location management. These include modeling of location information, uncertainty management, spatio-temporal data access languages, indexing and scalability issues, data mining (including traffic and location prediction), location dissemination, privacy and security, location fusion and synchronization.

Extending drive-thru data access by vehicle-to-vehicle relay

Abstract: Recently, some researchers have performed extensive experiments to study the feasibility and performance of vehicle drive-thru access to roadside access points (APs). The experiments demonstrate that the duration of connectivity to the AP is limited. A drive-thru vehicle has an area of high signal strength near the AP, but experiences poor link quality when entering or exiting the AP coverage area. Since a vehicle spends a large portion of the connection time in this poor link quality area, the data throughput can be significantly reduced. This problem has been identified in several works, but a viable solution has yet to be identified. In this paper, we propose a vehicle-to-vehicle relay (V2VR) scheme which extends the service range of roadside APs and allows drive-thru vehicles to maintain high throughput within an extended range. Our solution is distributed and purely client-based, without any modification to the existing 802.11 APs. Through implementation and simulation, we demonstrate that the V2VR scheme can effectively extend the drive-thru access range and improve the network utilization for drive-thru vehicles.