Pub Date : 2002-07-02DOI: 10.1109/ICDCS.2002.1022264
V. Zadorozhny, L. Raschid
Recent technology advances have enabled mediated query processing with Internet accessible WebSources. A characteristic of WebSources is that their access costs exhibit transient behavior These costs depend on the network and server workloads, which are often affected by, the time of day,, day, etc. Given transient behavior, an appropriate performance target (PT) for a noisy, environment will correspond to "at least X percentage of queries will have a latency of less than T units of time". In this paper we propose an optimizer strategy that is sensitive to the objective of meeting such performance targets (PT). For each query plan, a PT sensitive optimizer uses both the expected value of the cost distribution of the plan, as well as the expected delay, of the plan. We validate our strategy using a simulation based study of the optimizers behavior. We also experimentally validate the optimizer using traces of access costs for real WebSources.
{"title":"Query optimization to meet performance targets for wide area applications","authors":"V. Zadorozhny, L. Raschid","doi":"10.1109/ICDCS.2002.1022264","DOIUrl":"https://doi.org/10.1109/ICDCS.2002.1022264","url":null,"abstract":"Recent technology advances have enabled mediated query processing with Internet accessible WebSources. A characteristic of WebSources is that their access costs exhibit transient behavior These costs depend on the network and server workloads, which are often affected by, the time of day,, day, etc. Given transient behavior, an appropriate performance target (PT) for a noisy, environment will correspond to \"at least X percentage of queries will have a latency of less than T units of time\". In this paper we propose an optimizer strategy that is sensitive to the objective of meeting such performance targets (PT). For each query plan, a PT sensitive optimizer uses both the expected value of the cost distribution of the plan, as well as the expected delay, of the plan. We validate our strategy using a simulation based study of the optimizers behavior. We also experimentally validate the optimizer using traces of access costs for real WebSources.","PeriodicalId":186210,"journal":{"name":"Proceedings 22nd International Conference on Distributed Computing Systems","volume":"292 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123744563","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-07-02DOI: 10.1109/ICDCS.2002.1022302
A. Amer, D. Long, R. Burns
We describe a way to manage distributed file system caches based upon groups of files that are accessed together. We use file access patterns to automatically construct dynamic groupings of files and then manage our cache by fetching groups, rather than single files. We present experimental results, based on trace-driven workloads, demonstrating that grouping improves cache performance. At the file system client, grouping can reduce LRU demand fetches by 50 to 60%. At the server cache hit rate improvements are much more pronounced, but vary widely (20 to over 1200%) depending upon the capacity of intervening caches. Our treatment includes information theoretic results that justify our approach to file grouping.
{"title":"Group-based management of distributed file caches","authors":"A. Amer, D. Long, R. Burns","doi":"10.1109/ICDCS.2002.1022302","DOIUrl":"https://doi.org/10.1109/ICDCS.2002.1022302","url":null,"abstract":"We describe a way to manage distributed file system caches based upon groups of files that are accessed together. We use file access patterns to automatically construct dynamic groupings of files and then manage our cache by fetching groups, rather than single files. We present experimental results, based on trace-driven workloads, demonstrating that grouping improves cache performance. At the file system client, grouping can reduce LRU demand fetches by 50 to 60%. At the server cache hit rate improvements are much more pronounced, but vary widely (20 to over 1200%) depending upon the capacity of intervening caches. Our treatment includes information theoretic results that justify our approach to file grouping.","PeriodicalId":186210,"journal":{"name":"Proceedings 22nd International Conference on Distributed Computing Systems","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126991620","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-07-02DOI: 10.1109/ICDCS.2002.1022298
J. Holliday, D. Agrawal, A. E. Abbadi
Data replication in distributed databases has been investigated extensively with the hope that it will improve performance, reliability, and availability. However the growth of the Internet has shown us that current replica management do not work well when the replicas are connected by an unreliable network, subject to congestion and dynamic topology changes. In this paper we present a replica update protocol that handles an adaptive partial replication scheme on such a network.
{"title":"Partial database replication using epidemic communication","authors":"J. Holliday, D. Agrawal, A. E. Abbadi","doi":"10.1109/ICDCS.2002.1022298","DOIUrl":"https://doi.org/10.1109/ICDCS.2002.1022298","url":null,"abstract":"Data replication in distributed databases has been investigated extensively with the hope that it will improve performance, reliability, and availability. However the growth of the Internet has shown us that current replica management do not work well when the replicas are connected by an unreliable network, subject to congestion and dynamic topology changes. In this paper we present a replica update protocol that handles an adaptive partial replication scheme on such a network.","PeriodicalId":186210,"journal":{"name":"Proceedings 22nd International Conference on Distributed Computing Systems","volume":"222 5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116016220","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-07-02DOI: 10.1109/ICDCS.2002.1022278
Xuejun Chen
By using dynamic reconfiguration, the flexibility, adaptability, and extensibility of distributed systems are enhanced. Treating interactions among components during dynamic reconfiguration is still one of the most crucial problems in this research area. This challenge should be met by middleware design and development. However, current standard middleware offers little support for dynamic reconfiguration of distributed systems. In this paper, we describe an extended Java RMI that supports efficiently dynamic reconfiguration of distributed systems. This extended Java RMI can automatically monitor and manipulate invocations between components during dynamic reconfiguration. Moreover, the extended Java RMI can automatically switch invocations from remote to local and vice versa.
{"title":"Extending RMI to support dynamic reconfiguration of distributed systems","authors":"Xuejun Chen","doi":"10.1109/ICDCS.2002.1022278","DOIUrl":"https://doi.org/10.1109/ICDCS.2002.1022278","url":null,"abstract":"By using dynamic reconfiguration, the flexibility, adaptability, and extensibility of distributed systems are enhanced. Treating interactions among components during dynamic reconfiguration is still one of the most crucial problems in this research area. This challenge should be met by middleware design and development. However, current standard middleware offers little support for dynamic reconfiguration of distributed systems. In this paper, we describe an extended Java RMI that supports efficiently dynamic reconfiguration of distributed systems. This extended Java RMI can automatically monitor and manipulate invocations between components during dynamic reconfiguration. Moreover, the extended Java RMI can automatically switch invocations from remote to local and vice versa.","PeriodicalId":186210,"journal":{"name":"Proceedings 22nd International Conference on Distributed Computing Systems","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116567775","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-07-02DOI: 10.1109/ICDCS.2002.1022265
T. Yamashita
This paper proposes a replica control method based on a fairly assigned variation of numerical data that has weak consistency for loosely coupled systems managed or used by different organizations. This method dynamically distributes the variation of numerical data to replicas according to their demands while achieving fairness among them. By assigning the variation, a replica can determine the possibility that processed update transactions will be aborted and can notify a client of the possibility even when network partitioning happens. In addition, fairly, assigning the variation of data to replicas enables the disadvantage among replicas caused by asynchronous update to be balanced among replicas. Fairness control for assigning the variation of data is performed by averaging the demands in the variation that are requested by the replicas. Simulation showed that our system can achieve extremely high fairness while processing update transactions at the maximum rate.
{"title":"Dynamic replica control based on fairly assigned variation of data with weak consistency for loosely coupled distributed systems","authors":"T. Yamashita","doi":"10.1109/ICDCS.2002.1022265","DOIUrl":"https://doi.org/10.1109/ICDCS.2002.1022265","url":null,"abstract":"This paper proposes a replica control method based on a fairly assigned variation of numerical data that has weak consistency for loosely coupled systems managed or used by different organizations. This method dynamically distributes the variation of numerical data to replicas according to their demands while achieving fairness among them. By assigning the variation, a replica can determine the possibility that processed update transactions will be aborted and can notify a client of the possibility even when network partitioning happens. In addition, fairly, assigning the variation of data to replicas enables the disadvantage among replicas caused by asynchronous update to be balanced among replicas. Fairness control for assigning the variation of data is performed by averaging the demands in the variation that are requested by the replicas. Simulation showed that our system can achieve extremely high fairness while processing update transactions at the maximum rate.","PeriodicalId":186210,"journal":{"name":"Proceedings 22nd International Conference on Distributed Computing Systems","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114468030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-07-02DOI: 10.1109/ICDCS.2002.1022268
Xiaohui Gu, K. Nahrstedt
Ubiquitous computing promotes the proliferation of various stationary, embedded and mobile devices interconnected by heterogeneous networks. It leads to a highly dynamic distributed system with many devices and services coming and going frequently. Many emerging distributed multimedia applications are being deployed in such a computing environment. In order to make the experience for a user truly seamless and to provide soft performance guarantees, we must meet the following challenges: (1) users should be able to perform tasks continuously, despite changes of resources, devices and locations; (2) users should be able to efficiently utilize all accessible resources within runtime environments to receive the best possible Quality-of-Service (QoS). In this paper, we propose an integrated QoS-aware service configuration model to address the above problems. The configuration model includes two tiers: (1) service composition tier, which is responsible for choosing and composing current available service components appropriately and coordinating arbitrary interactions between them to achieve the user's objectives; and (2) service distribution tier which is responsible for dividing an application into several partitions and distributing them to different available devices appropriately. Our initial experimental results based on both prototype and simulations show the soundness of our model and algorithms.
{"title":"Dynamic QoS-aware multimedia service configuration in ubiquitous computing environments","authors":"Xiaohui Gu, K. Nahrstedt","doi":"10.1109/ICDCS.2002.1022268","DOIUrl":"https://doi.org/10.1109/ICDCS.2002.1022268","url":null,"abstract":"Ubiquitous computing promotes the proliferation of various stationary, embedded and mobile devices interconnected by heterogeneous networks. It leads to a highly dynamic distributed system with many devices and services coming and going frequently. Many emerging distributed multimedia applications are being deployed in such a computing environment. In order to make the experience for a user truly seamless and to provide soft performance guarantees, we must meet the following challenges: (1) users should be able to perform tasks continuously, despite changes of resources, devices and locations; (2) users should be able to efficiently utilize all accessible resources within runtime environments to receive the best possible Quality-of-Service (QoS). In this paper, we propose an integrated QoS-aware service configuration model to address the above problems. The configuration model includes two tiers: (1) service composition tier, which is responsible for choosing and composing current available service components appropriately and coordinating arbitrary interactions between them to achieve the user's objectives; and (2) service distribution tier which is responsible for dividing an application into several partitions and distributing them to different available devices appropriately. Our initial experimental results based on both prototype and simulations show the soundness of our model and algorithms.","PeriodicalId":186210,"journal":{"name":"Proceedings 22nd International Conference on Distributed Computing Systems","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121930630","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-07-02DOI: 10.1109/ICDCS.2002.1022284
Wei Fan, Haixun Wang, Philip S. Yu, S. Stolfo
We propose a fully distributed system (as compared to centralized and partially distributed systems) for cost-sensitive data mining. Experimental results have shown that this approach achieves higher accuracy than both the centralized and partially distributed learning methods, however, it incurs much less training time, neither communication nor computation overhead.
{"title":"A fully distributed framework for cost-sensitive data mining","authors":"Wei Fan, Haixun Wang, Philip S. Yu, S. Stolfo","doi":"10.1109/ICDCS.2002.1022284","DOIUrl":"https://doi.org/10.1109/ICDCS.2002.1022284","url":null,"abstract":"We propose a fully distributed system (as compared to centralized and partially distributed systems) for cost-sensitive data mining. Experimental results have shown that this approach achieves higher accuracy than both the centralized and partially distributed learning methods, however, it incurs much less training time, neither communication nor computation overhead.","PeriodicalId":186210,"journal":{"name":"Proceedings 22nd International Conference on Distributed Computing Systems","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124554405","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-07-02DOI: 10.1109/ICDCS.2002.1022311
U. Schmid, Bettina Weiss, J. Rushby
This paper shows that deterministic consensus in synchronous distributed systems with link faults is possible, despite the impossibility result of Gray (1978). Instead of using randomization, we overcome this impossibility by moderately restricting the inconsistency that link faults may cause system-wide. Relying upon a novel hybrid fault model that provides different classes of faults for both nodes and links, we provide a formally verified proof that the m+1-round Byzantine agreement algorithm OMH (Lincoln and Rushby (1993)) requires n > 2f/sub l//sup s/ + f/sub l//sup r/ + f/sub l//sup ra/ + 2(f/sub a/ + f/sub s/) + f/sub o/ + f/sub m/ + m nodes for transparently masking at most f/sub l//sup s/ broadcast and f/sub l//sup r/ receive link faults (including at most f/sub l//sup ra/ arbitrary ones) per node in each round, in addition to at most f/sub a/, f/sub s/, f/sub o/, f/sub m/ arbitrary, symmetric, omission, and manifest node faults, provided that m /spl ges/ f/sub a/ + f/sub o/ + 1. Our approach to modeling link faults is justified by a number of theoretical results, which include tight lower bounds for the required number of nodes and an analysis of the assumption coverage in systems where links fail independently with some probability p.
本文表明，尽管Gray(1978)给出了不可能的结果，但在链路故障的同步分布式系统中，确定性共识是可能的。我们没有使用随机化，而是通过适度限制链路故障可能导致系统范围内的不一致性来克服这种不可能性。基于一种新型的混合故障模型，该模型为节点和链路提供了不同类型的故障，我们提供一个正式验证证明了m + 1轮拜占庭协议算法OMH(林肯和Rushby(1993))需要n > 2 f /子l / /一口s / + f /子l / /一口r / + f /子l / /呷拉/ + 2 (f /子/ + f /子s /) + f /子o / m + f / m / +节点最多透明屏蔽f /子l / l /一口s /广播和f /子/ /一口r /接收链路故障(包括最多f /子l / /呷拉/任意的)每个节点在每一轮中,除了最多f /子/ f / sub s / f /下标o /, f / m /武断,对称、遗漏和明显节点故障，前提是m /spl为/ f/sub a/ + f/sub o/ + 1。我们对链路故障建模的方法得到了许多理论结果的证明，其中包括所需节点数量的严格下界，以及对链路以一定概率p独立故障的系统中的假设覆盖范围的分析。
{"title":"Formally verified Byzantine agreement in presence of link faults","authors":"U. Schmid, Bettina Weiss, J. Rushby","doi":"10.1109/ICDCS.2002.1022311","DOIUrl":"https://doi.org/10.1109/ICDCS.2002.1022311","url":null,"abstract":"This paper shows that deterministic consensus in synchronous distributed systems with link faults is possible, despite the impossibility result of Gray (1978). Instead of using randomization, we overcome this impossibility by moderately restricting the inconsistency that link faults may cause system-wide. Relying upon a novel hybrid fault model that provides different classes of faults for both nodes and links, we provide a formally verified proof that the m+1-round Byzantine agreement algorithm OMH (Lincoln and Rushby (1993)) requires n > 2f/sub l//sup s/ + f/sub l//sup r/ + f/sub l//sup ra/ + 2(f/sub a/ + f/sub s/) + f/sub o/ + f/sub m/ + m nodes for transparently masking at most f/sub l//sup s/ broadcast and f/sub l//sup r/ receive link faults (including at most f/sub l//sup ra/ arbitrary ones) per node in each round, in addition to at most f/sub a/, f/sub s/, f/sub o/, f/sub m/ arbitrary, symmetric, omission, and manifest node faults, provided that m /spl ges/ f/sub a/ + f/sub o/ + 1. Our approach to modeling link faults is justified by a number of theoretical results, which include tight lower bounds for the required number of nodes and an analysis of the assumption coverage in systems where links fail independently with some probability p.","PeriodicalId":186210,"journal":{"name":"Proceedings 22nd International Conference on Distributed Computing Systems","volume":"124 3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126272225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-07-02DOI: 10.1109/ICDCS.2002.1022240
Songqing Chen, Li Xiao, Xiaodong Zhang
In a cluster system with dynamic load sharing support, a job submission or migration to a workstation is determined by the availability of CPU and memory resources of the workstation at the time. In such a system, a small number of running jobs with unexpectedly large memory allocation requirements may significantly increase the queuing delay times of the rest of jobs with normal memory requirements, slowing down executions of individual jobs and decreasing the system throughput. We call this phenomenon as the job blocking problem because the big jobs block the execution pace of majority jobs in the cluster. We propose a software method incorporating with dynamic load sharing, which adaptively reserves a small set of workstations through virtual cluster reconfiguration to provide special services to the jobs demanding large memory allocations. This policy implies the principle of shortest-remaining-processing-time policy. As soon as the blocking problem is resolved by the reconfiguration, the system will adaptively switch back to the normal load sharing state. We present three contributions in this study. (1) the conditions to cause the job blocking problem; (2) the adaptive software method in a dynamic load sharing system; and (3) trace-driven simulations. We show that our method can effectively improve the cluster computing performance by quickly resolving the job blocking problem. The effectiveness and performance insights are also analytically verified.
{"title":"Adaptive and virtual reconfigurations for effective dynamic job scheduling in cluster systems","authors":"Songqing Chen, Li Xiao, Xiaodong Zhang","doi":"10.1109/ICDCS.2002.1022240","DOIUrl":"https://doi.org/10.1109/ICDCS.2002.1022240","url":null,"abstract":"In a cluster system with dynamic load sharing support, a job submission or migration to a workstation is determined by the availability of CPU and memory resources of the workstation at the time. In such a system, a small number of running jobs with unexpectedly large memory allocation requirements may significantly increase the queuing delay times of the rest of jobs with normal memory requirements, slowing down executions of individual jobs and decreasing the system throughput. We call this phenomenon as the job blocking problem because the big jobs block the execution pace of majority jobs in the cluster. We propose a software method incorporating with dynamic load sharing, which adaptively reserves a small set of workstations through virtual cluster reconfiguration to provide special services to the jobs demanding large memory allocations. This policy implies the principle of shortest-remaining-processing-time policy. As soon as the blocking problem is resolved by the reconfiguration, the system will adaptively switch back to the normal load sharing state. We present three contributions in this study. (1) the conditions to cause the job blocking problem; (2) the adaptive software method in a dynamic load sharing system; and (3) trace-driven simulations. We show that our method can effectively improve the cluster computing performance by quickly resolving the job blocking problem. The effectiveness and performance insights are also analytically verified.","PeriodicalId":186210,"journal":{"name":"Proceedings 22nd International Conference on Distributed Computing Systems","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129220319","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-07-02DOI: 10.1109/ICDCS.2002.1022282
SangKeun Lee, C. Hwang, M. Kitsuregawa
Wireless data broadcast allows a large number of users to retrieve data simultaneously in mobile databases, resulting in an efficient way of using the scarce wireless bandwidth. The efficiency of data access methods, however, is limited by an inherent property that data can only be accessed strictly sequentially by users. The paper addresses the issue of ensuring consistency and currency of data items requested in a certain order by wireless read-only transactions. To properly cope with the inherent property of data broadcast, we explore a predeclaration-based query optimization and devise three predeclaration-based transaction processing methods.
{"title":"Using predeclaration for efficient read-only transaction processing in wireless data broadcast","authors":"SangKeun Lee, C. Hwang, M. Kitsuregawa","doi":"10.1109/ICDCS.2002.1022282","DOIUrl":"https://doi.org/10.1109/ICDCS.2002.1022282","url":null,"abstract":"Wireless data broadcast allows a large number of users to retrieve data simultaneously in mobile databases, resulting in an efficient way of using the scarce wireless bandwidth. The efficiency of data access methods, however, is limited by an inherent property that data can only be accessed strictly sequentially by users. The paper addresses the issue of ensuring consistency and currency of data items requested in a certain order by wireless read-only transactions. To properly cope with the inherent property of data broadcast, we explore a predeclaration-based query optimization and devise three predeclaration-based transaction processing methods.","PeriodicalId":186210,"journal":{"name":"Proceedings 22nd International Conference on Distributed Computing Systems","volume":"64 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124807921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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