Minimisation of the update response time in a distributed database system

Maalouf, Hoda W.; Gurcan, M.K.

doi:10.1016/s0166-5316(02)00085-8

Cited by 13 publications

(4 citation statements)

References 7 publications

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“…Requests for data within the network and arrival of data updates at the server are assumed to be random homogenous Poisson processes, and thus the interarrival times are represented by exponential random variables, as was suggested in [14] and [42]. We use R to denote the rate of requests and U for the item update rate, and suppose that each query or data item can have its own rate.…”

Section: Discussionmentioning

confidence: 99%

DCIM: Distributed Cache Invalidation Method for Maintaining Cache Consistency in Wireless Mobile Networks

Fawaz

Artail

2013

IEEE Trans. on Mobile Comput.

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Abstract-This paper proposes distributed cache invalidation mechanism (DCIM), a client-based cache consistency scheme that is implemented on top of a previously proposed architecture for caching data items in mobile ad hoc networks (MANETs), namely COACS, where special nodes cache the queries and the addresses of the nodes that store the responses to these queries. We have also previously proposed a server-based consistency scheme, named SSUM, whereas in this paper, we introduce DCIM that is totally client-based. DCIM is a pull-based algorithm that implements adaptive time to live (TTL), piggybacking, and prefetching, and provides near strong consistency capabilities. Cached data items are assigned adaptive TTL values that correspond to their update rates at the data source, where items with expired TTL values are grouped in validation requests to the data source to refresh them, whereas unexpired ones but with high request rates are prefetched from the server. In this paper, DCIM is analyzed to assess the delay and bandwidth gains (or costs) when compared to polling every time and push-based schemes. DCIM was also implemented using ns2, and compared against client-based and server-based schemes to assess its performance experimentally. The consistency ratio, delay, and overhead traffic are reported versus several variables, where DCIM showed to be superior when compared to the other systems.

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Section: Discussionmentioning

confidence: 99%

DCIM: Distributed Cache Invalidation Method for Maintaining Cache Consistency in Wireless Mobile Networks

Fawaz

Artail

2013

IEEE Trans. on Mobile Comput.

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“…These are the differences between the corresponding measures when no cache updating is in place and when SSUM is employed. Requests for data in the ad hoc network and data updates at the server are assumed to be random processes and may be represented by exponential random variables, as was suggested in [4] and [25]. We use R to denote the rate of requests and U the rate of updates.…”

Section: Discussionmentioning

confidence: 99%

SSUM: Smart Server Update Mechanism for Maintaining Cache Consistency in Mobile Environments

Mershad

Artail

2010

IEEE Trans. on Mobile Comput.

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This paper proposes a cache consistency scheme based on a previously proposed architecture for caching database data in MANETs. The original scheme for data caching stores the queries that are submitted by requesting nodes in special nodes, called query directories (QDs), and uses these queries to locate the data (responses) that are stored in the nodes that requested them, called caching nodes (CNs). The consistency scheme is server-based in which control mechanisms are implemented to adapt the process of caching a data item and updating it by the server to its popularity and its data update rate at the server. The system implements methods to handle disconnections of QD and CN nodes from the network and to control how the cache of each node is updated or discarded when it returns to the network. Estimates for the average response time of node requests and the average node bandwidth utilization are derived in order to determine the gains (or costs) of employing our scheme in the MANET. Moreover, ns2 simulations were performed to measure several parameters, like the average data request response time, cache update delay, hit ratio, and bandwidth utilization. The results demonstrate the advantage of the proposed scheme over existing systems.

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“…RELATED WORK The performance of various resequencing systems has been investigated in [4], [5], [6]. Although the resequencing problem has been extensively studied for one-stage disordering systems, very few studies have investigated the multi-stage disordering systems which are, by nature, difficult to analyse.…”

Section: B Examplementioning

confidence: 99%

Packet resequencing and aggregation in wireless ad hoc networks

Maalouf

Aakvaag²

2008

2008 IEEE International Symposium on Wireless Communication Systems

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Packet disordering and resequencing is a common problem in many real-time applications with stringent timing constraints. A typical scenario is when wireless sensor nodes, interconnected with an ad hoc network, are used to monitor a certain event. In such systems, packets will have to be resequenced before consumption because they were disordered while traversing different paths over the ad hoc network. In this paper, we analyze the impact of the wireless network on packet resequencing and aggregation. We propose an en-route resequencing/aggregation technique which minimizes the resequencing delay, optimizes the usage of the available bandwidth and gives better end-to-end delay performance than end-to-end resequencing in wireless ad hoc networks.

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Minimisation of the update response time in a distributed database system

Cited by 13 publications

References 7 publications

DCIM: Distributed Cache Invalidation Method for Maintaining Cache Consistency in Wireless Mobile Networks

DCIM: Distributed Cache Invalidation Method for Maintaining Cache Consistency in Wireless Mobile Networks

SSUM: Smart Server Update Mechanism for Maintaining Cache Consistency in Mobile Environments

Packet resequencing and aggregation in wireless ad hoc networks

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