scispace - formally typeset
Search or ask a question
Proceedings ArticleDOI

Energy-efficient caching for wireless mobile computing

26 Feb 1996-pp 336-343
TL;DR: An energy-efficient cache invalidation method, called GCORE (Grouping with COld update-set REtention), that allows a mobile computer to operate in a disconnected mode to save the battery while still retaining most of the caching benefits after a reconnection is presented.
Abstract: Caching can reduce the bandwidth requirement in a mobile computing environment. However, due to battery power limitations, a wireless mobile computer may often be forced to operate in a doze (or even totally disconnected) mode. As a result, the mobile computer may miss some cache invalidation reports broadcast by a server, forcing it to discard the entire cache contents after waking up. In this paper, we present an energy-efficient cache invalidation method, called GCORE (Grouping with COld update-set REtention), that allows a mobile computer to operate in a disconnected mode to save the battery while still retaining most of the caching benefits after a reconnection. We present an efficient implementation of GCORE and conduct simulations to evaluate its caching effectiveness. The results show that GCORE can substantially improve mobile caching by reducing the communication bandwidth (or energy consumption) for query processing.
Citations
More filters
Journal ArticleDOI
01 Feb 1999
TL;DR: The results show that the proposed algorithm can generate programs that lead to significant improvement (in terms of both access time and tuning time) for range queries without sacrificing much on the performance of single object retrievals.
Abstract: In a wireless computing environment, a server disseminates information by periodically broadcasting data on ‘air’, while clients ‘catch’ their desired data on the fly. To determine the data to be broadcast, the server constructs a broadcast program. While a nonuniform broadcast program has been demonstrated to be effective in reducing the average access times for single-record retrievals, existing nonuniform broadcast programs perform poorly for range queries. In this paper, we propose a new algorithm to generate nonuniform broadcast programs that can facilitate range queries. Our algorithm supports selective tuning using the flexible indexing scheme. We conducted an extensive simulation study, and our results show that the proposed algorithm can generate programs that lead to significant improvement (in terms of both access time and tuning time) for range queries without sacrificing much on the performance of single object retrievals.

10 citations


Cites background from "Energy-efficient caching for wirele..."

  • ...Caching and cache coherency problem are orthogonal issues and have been addressed in [2,3,11,15,19]....

    [...]

Journal Article
TL;DR: A new cache replacement strategy is proposed, the Least Unified Value strategy (LUV) to replace the Le least Recently Used (LRU) that SACCS was based on, and the advantages and the drawbacks of the new proposed strategy are studied, comparing it with different categories of cache replacement strategies.

10 citations


Cites methods from "Energy-efficient caching for wirele..."

  • ...The stateful approaches were suggested by Barbara and Imielinski [1][3][9][10][11][12][13][14]....

    [...]

Book ChapterDOI
TL;DR: The proposed protocol adopts aperiodic broadcasting as the cache invalidation scheme, and supports transaction semantics in mobile environments, and can improve the throughput by reducing the abortion of transactions with low communication costs.
Abstract: In mobile client-server database systems, caching of frequently accessed data is an important technique that will reduce the contention on the narrow bandwidth wireless channel. As the server in mobile environments may not have any information about the state of its clients' cache(stateless server), using broadcasting approach to transmit the updated data lists to numerous concurrent mobile clients is an attractive approach. In this paper, a caching policy is proposed to maintain cache consistency for mobile computers. The proposed protocol adopts aperiodic broadcasting as the cache invalidation scheme, and supports transaction semantics in mobile environments. With the aperiodic broadcasting approach, the proposed protocol can improve the throughput by reducing the abortion of transactions with low communication costs. We study the performance of the protocol by means of simulation experiments.

9 citations

Journal ArticleDOI
TL;DR: A new hybrid cache invalidation scheme is proposed that makes use of data mining concepts and is compared with other related strategies for improving cache consistency solutions.
Abstract: Caching in mobile environments is used for improving bandwidth usage and reducing query delays among resource constrained devices. It is used in multitudes of approaches. Some rely on the server occasionally broadcasting reports to inform clients of updated data while others permit clients to access data whenever they need it. Caching can be constrained by size and bandwidth; thus, coming up with a good invalidation scheme is critical in improving cache consistency solutions. In this work, the authors propose a new hybrid cache invalidation scheme that makes use of data mining concepts. They also compare their scheme with other related strategies.

8 citations


Cites background from "Energy-efficient caching for wirele..."

  • ...Other work such as Wu et al. (1996) suggested that the mobile unit needs to reply back to server with IDs of all the data objects cached with their corresponding timestamps when they get reconnected following a substantial amount of disconnection, and then after that the server 12 more pages are…...

    [...]

Journal ArticleDOI
01 Nov 2007
TL;DR: This scheme attempts to increase cache reusability by respecting update rates at a server, broadcast intervals, the communication bandwidth, and data sizes, as well as disconnection time, and results show that the increased cacheReusability of the scheme can improve the data access time after a long disconnection.
Abstract: Data broadcasting is an efficient data dissemination method in a wireless client-server system. A data server broadcasts data items periodically, and mobile clients cache data items to save communication bandwidth, resource usage, and data access time. The server also broadcasts invalidation reports (IRs) to maintain the consistency between server data and the clients' cached data. Most existing cache invalidation policies in a wireless environment based on IRs simply purge the entire cache after a client has been disconnected long enough to miss a certain number (window size) of IRs. We present a cache invalidation scheme that provides better cache reusability and better data access time after a long disconnection. Our scheme attempts to increase cache reusability by respecting update rates at a server, broadcast intervals, the communication bandwidth, and data sizes, as well as disconnection time. Simulation results show that the increased cache reusability of our scheme can improve the data access time after a long disconnection.

8 citations

References
More filters
Proceedings Article
01 Jan 1995
TL;DR: In this paper, a taxonomy of different cache invalidation strategies and study the impact of client's disconnection times on their performance is presented, and the authors determine that for the units which are often disconnected (sleepers) the best cache invalidization strategy is based on signatures previously used for efficient file comparison.
Abstract: In the mobile wireless computing environment of the future a large number of users equipped with low powered palm-top machines will query databases over the wireless communication channels. Palmtop based units will often be disconnected for prolonged periods of time due to the battery power saving measures; palmtops will also frequencly relocate between different cells and connect to different data servers at different times. Caching of frequently accessed data items will be an important technique that will reduce contention on the narrow bandwidth wireless channel. However, cache invalidation strategies will be severely affected by the disconnection and mobility of the clients. The server may no longer know which clients are currently residing under its cell and which of them are currently on. We propose a taxonomy of different cache invalidation strategies and study the impact of client's disconnection times on their performance. We determine that for the units which are often disconnected (sleepers) the best cache invalidation strategy is based on signatures previously used for efficient file comparison. On the other hand, for units which are connected most of the time (workaholics), the best cache invalidation strategy is based on the periodic broadcast of changed data items.

509 citations

Proceedings ArticleDOI
24 May 1994
TL;DR: A taxonomy of different cache invalidation strategies is proposed and it is determined that for the units which are often disconnected (sleepers) the best cache invalidations strategy is based on signatures previously used for efficient file comparison, and for units which is connected most of the time (workaholics), the best Cache invalidation strategy isbased on the periodic broadcast of changed data items.
Abstract: In the mobile wireless computing environment of the future a large number of users equipped with low powered palm-top machines will query databases over the wireless communication channels. Palmtop based units will often be disconnected for prolonged periods of time due to the battery power saving measures; palmtops will also frequencly relocate between different cells and connect to different data servers at different times. Caching of frequently accessed data items will be an important technique that will reduce contention on the narrow bandwidth wireless channel. However, cache invalidation strategies will be severely affected by the disconnection and mobility of the clients. The server may no longer know which clients are currently residing under its cell and which of them are currently on. We propose a taxonomy of different cache invalidation strategies and study the impact of client's disconnection times on their performance. We determine that for the units which are often disconnected (sleepers) the best cache invalidation strategy is based on signatures previously used for efficient file comparison. On the other hand, for units which are connected most of the time (workaholics), the best cache invalidation strategy is based on the periodic broadcast of changed data items.

454 citations

Proceedings ArticleDOI
24 May 1994
TL;DR: This work describes two methods, (1,m) Indexing and Distributed Indexing, for organizing and accessing broadcast data and demonstrates that the proposed algorithms lead to significant improvement of battery life, while retaining a low access time.
Abstract: We consider wireless broadcasting of data as a way of disseminating information to a massive number of users. Organizing and accessing information on wireless communication channels is different from the problem of organizing and accessing data on the disk. We describe two methods, (1,m) Indexing and Distributed Indexing, for organizing and accessing broadcast data. We demonstrate that the proposed algorithms lead to significant improvement of battery life, while retaining a low access time.

421 citations

Journal ArticleDOI
TL;DR: The author begins by discussing the background, defining key terms and showing how wireless information systems can be viewed as a natural evolution of computing's relentless march toward greater distribution and ubiquity of access.
Abstract: The author begins by discussing the background, defining key terms and showing how wireless information systems can be viewed as a natural evolution of computing's relentless march toward greater distribution and ubiquity of access. Next, the research issues faced by designers of wireless information systems are detailed, and some large-scale engineering challenges for such designers are presented. The existing cellular system architecture, evolved from telephony, is compared with an alternative architecture more closely integrated with a computer networking view of wireless systems. Existing wireless systems are reviewed, and the final section presents the author's summary and conclusions, and charts the future of wireless information systems. >

321 citations

Trending Questions (1)
How to clear browser cache in Robot Framework?

As a result, the mobile computer may miss some cache invalidation reports broadcast by a server, forcing it to discard the entire cache contents after waking up.