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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
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Proceedings ArticleDOI
06 Jun 2005
TL;DR: Simulation results demonstrated that RPCC outperforms the traditional push and pull based strategies by taking their advantages while at the same time avoiding their weakness.
Abstract: Caching consistency is an important issue for cooperative caching in mobile environments but has not been adequately addressed for mobile ad hoc networks (MANETs). In this paper, we proposed a novel approach, called RPCC (relay peer-based caching consistency), to addressing the caching consistency issues in a MANET. With the help of relay peers between the source host and cache hosts, both push-based and pull-based strategies can be employed, which helps to reduce the communication overhead and query latency. The source host pushes the data to relay peers and cache hosts pull the data from relay peers. These operations can be performed asynchronously and simultaneously. Moreover, the proposed RPCC approach is flexible in that it can deal with different consistency requirements adaptively. Simulation results demonstrated that RPCC outperforms the traditional push and pull based strategies by taking their advantages while at the same time avoiding their weakness.

30 citations


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

  • ...Cache consistency maintenance techniques have been widely studied in the traditional client/server systems[6, 1, 13, 11, 7, 14, 8, 2, 12]....

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Proceedings ArticleDOI
19 May 2003
TL;DR: Comprehensive simulation results show that the performance of SACCS is superior to those of existing algorithms.
Abstract: In this paper, we propose a novel cache consistency maintenance scheme, called Scalable Asynchronous Cache Consistency Scheme (SACCS), for mobile environments. It relies on the following three key features: (1) Use of flag bits at server and MU's cache to maintain cache consistency; (2) Use of an identifier (ID) for each entry in MUs cache after its invalidation in order to maximize the broadcast bandwidth efficiency; (3) Rendering all valid entries of MUs cache to uncertain state when it wakes up. These three features make the SACCS a highly scalable algorithm with minimum database management overhead. Comprehensive simulation results show that the performance of SACCS is superior to those of existing algorithms.

30 citations


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

  • ...[5] proposed an uplink validation check scheme that can deal with long sleep-wakeup patterns better than TS and AT....

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Journal ArticleDOI
TL;DR: In this paper, popular broadcast scheduling approaches are tested from an implementation cost aspect, and the results render them only conditionally realizable, and a new, cost-effective, adaptivity oriented schedule constructor is proposed as a realistic, minimal-cost solution.
Abstract: A main design issue in a wireless data broadcasting system is to choose between push-based and pull-based logic: The former is used as a low-cost solution, while the latter is preferred when performance is of utmost importance. Therefore, the most significant advantage of a push system is the minimal cost. This fact implies that hardware limitations do exist in the case of push systems. As a consequence, every related proposed algorithm should primarily be cost-effective. This attribute, however, has been overlooked in related research. In this paper, popular broadcast scheduling approaches are tested from an implementation cost aspect, and the results render them only conditionally realizable. Moreover, a new, cost-effective, adaptivity oriented schedule constructor is proposed as a realistic, minimal-cost solution.

30 citations

Journal ArticleDOI
TL;DR: A secure spontaneous ad-hoc network, based on direct peer-to-peer interaction, to grant a quick, easy, and secure access to the users to surf the Web, developed with the main objective of improving the communication and integration between different study centers of low-resource communities.
Abstract: In this paper, we propose a secure spontaneous ad-hoc network, based on direct peer-to-peer interaction, to grant a quick, easy, and secure access to the users to surf the Web. The paper shows the description of our proposal, the procedure of the nodes involved in the system, the security algorithms implemented, and the designed messages. We have taken into account the security and its performance. Although some people have defined and described the main features of spontaneous ad-hoc networks, nobody has published any design and simulation until today. Spontaneous networking will enable a more natural form of wireless computing when people physically meet in the real world. We also validate the success of our proposal through several simulations and comparisons with a regular architecture, taking into account the optimization of the resources of the devices. Finally, we compare our proposal with other caching techniques published in the related literature. The proposal has been developed with the main objective of improving the communication and integration between different study centers of low-resource communities. That is, it lets communicate spontaneous networks, which are working collaboratively and which have been created on different physical places.

29 citations

Journal ArticleDOI
TL;DR: A mathematical analysis of the broadcast disks method is presented, which establishes a new analytical performance-optimization procedure and showed that even small deviations from optimal parameter values may lead to significant performance degradation in terms of the clients' mean waiting time.
Abstract: The role of the push-based architecture in modern wireless telecommunication systems has been gaining momentum over the past few years. However, these systems pose a challenging problem: the creation of the optimal common broadcast schedule that best fits the needs of the totality of the available clients. To this end, various approaches have been proposed, with one of the most well known and widely accepted approaches being the broadcast disks method. This method ensures the periodicity and proportionality attributes of the broadcast schedule but leaves ample room for performance optimization, which is a task traditionally assigned to heuristic algorithms. This paper presents a mathematical analysis of the broadcast disks method, which establishes a new analytical performance-optimization procedure. Comparison with other related well-known algorithms yielded better performance in every client test case. Finally, the analysis showed that even small deviations from optimal parameter values may lead to significant performance degradation in terms of the clients' mean waiting time.

29 citations


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

  • ...These broadcast schedule attributes have been proven to be very practical, and thus, the Broadcast Disks method has constituted the basis for many subsequent studies involving prefetching, caching [6], [7] and indexing of data [8], [9], hybrid data delivery [10], [11], and quality-ofservice-related broadcast scheduling strategies [12]–[15]....

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References
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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

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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.