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47
Flashdb: dynamic self-tuning database for nand flash
- In IPSN
, 2007
"... FlashDB is a self-tuning database optimized for sensor networks using NAND flash storage. In practical systems flash is used in different packages such as on-board flash chips, compact flash cards, secure digital cards and related formats. Our experiments reveal non-trivial differences in their acce ..."
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Cited by 84 (4 self)
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FlashDB is a self-tuning database optimized for sensor networks using NAND flash storage. In practical systems flash is used in different packages such as on-board flash chips, compact flash cards, secure digital cards and related formats. Our experiments reveal non-trivial differences in their access costs. Furthermore, databases may be subject to different types of workloads. We show that existing databases for flash are not optimized for all types of flash devices or for all workloads and their performance is thus suboptimal in many practical systems. FlashDB uses a novel self-tuning index that dynamically adapts its storage structure to workload and underlying storage device. We formalize the self-tuning nature of an index as a two-state task system and propose a 3-competitive online algorithm that achieves the theoretical optimum. We also provide a framework to determine the optimal size of an index node that minimizes energy and latency for a given device. Finally, we propose optimizations to further improve the performance of our index. We prototype and compare different indexing schemes on multiple flash devices and workloads, and show that our indexing scheme outperforms existing schemes under all workloads and flash devices we consider.
Theoretical Results on Base Station Movement Problem for Sensor Network
- In Proc. IEEE INFOCOM
, 2008
"... The benefits of using mobile base station to prolong sensor network lifetime have been well recognized. However, due to the complexity of the problem (time-dependent network topology and traffic routing), theoretical performance limit and provably optimal algorithms remain difficult to develop. This ..."
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Cited by 46 (5 self)
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The benefits of using mobile base station to prolong sensor network lifetime have been well recognized. However, due to the complexity of the problem (time-dependent network topology and traffic routing), theoretical performance limit and provably optimal algorithms remain difficult to develop. This paper fills this important gap by contributing theoretical results regarding the optimal movement of a mobile base station. Our main result hinges upon a novel transformation of the joint base station movement and flow routing problem from time domain to space domain. Based on this transformation, we first show if the base station is allowed to be present only on a set of pre-defined points, then we can find the optimal time duration for the base station on each of these points so that the overall network lifetime is maximized. Based on this finding, we show that when the location of the base station is un-constrained (i.e., can move to any point in the two-dimensional plane), we can develop an approximation algorithm for the joint mobile base station location and flow routing problem such that the network lifetime is guaranteed to be at least of the maximum network lifetime, where can be made arbitrarily small depending on required precision.
Dependable and Secure Sensor Data Storage with Dynamic Integrity Assurance
- Proc. IEEE INFOCOM, Apr. 2009. 684 IEEE TRANSACTIONS ON PARALLEL AND DISTRIBUTED SYSTEMS, VOL
, 2011
"... Abstract—Recently, distributed data storage has gained in-creasing popularity for efficient and robust data management in wireless sensor networks (WSNs). But the distributed architecture also makes it challenging to build a highly secure and dependable yet lightweight data storage system. On the on ..."
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Cited by 40 (9 self)
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Abstract—Recently, distributed data storage has gained in-creasing popularity for efficient and robust data management in wireless sensor networks (WSNs). But the distributed architecture also makes it challenging to build a highly secure and dependable yet lightweight data storage system. On the one hand, sensor data are subject to not only Byzantine failures, but also dynamic pollu-tion attacks, as along the time the adversary may modify/pollute the stored data by compromising individual sensors. On the other hand, the resource-constrained nature of WSNs precludes the applicability of heavyweight security designs. To address the challenges, we propose a novel dependable and secure data storage scheme with dynamic integrity assurance in this paper. Based on the principle of secret sharing and erasure coding, we first propose a hybrid share generation and distribution scheme to achieve reliable and fault-tolerant initial data storage by providing redundancy for original data components. To further dynamically ensure the integrity of the distributed data shares, we then propose an efficient data integrity verification scheme exploiting the technique of algebraic signatures. The proposed scheme enables individual sensors to verify in one protocol execution all the pertaining data shares simultaneously in the absence of the original data. Extensive security and performance analysis shows that the proposed schemes have strong resistance against various attacks and are practical for WSNs. I.
Securing Distributed Data Storage and Retrieval
- in Sensor Networks,” IEEE Conference on Pervasive Computing and Communications (PerCom
, 2007
"... Sensor networks have been an attractive platform for pervasive computing and communication. Due to the lack of physical protection, however, sensor networks are vulnerable to attacks if deployed in hostile environments. When a sensor network is under attack, the most fundamental concern is that info ..."
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Cited by 27 (2 self)
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Sensor networks have been an attractive platform for pervasive computing and communication. Due to the lack of physical protection, however, sensor networks are vulnerable to attacks if deployed in hostile environments. When a sensor network is under attack, the most fundamental concern is that information communicated or stored in the network remains safe. The past research has focused on securing information in communication, but how to secure information in storage has been generally overlooked. Meanwhile, distributed data storage and retrieval have become popular for efficient data management in sensor networks, which renders the absence of schemes for securing stored information to be a more severe problem. Hence, we propose in this paper three schemes to deal with the problem. All the schemes have the following properties: (i) Only authorized entities can access data stored in the sensor network; (ii) The schemes are resilient to a large number of sensor node compromises. The second and the third schemes do not involve any centralized entity except for a few initialization or renewal operations, and thus support secure, distributed data storage and retrieval. The third scheme further provides high scalability and flexibility, and hence is most suitable in real applications. The effectiveness and efficiency of the proposed schemes have also been verified through extensive analysis and TOSSIM-based simulations. 1.
EnviroMic: Towards Cooperative Storage and Retrieval in Audio Sensor Networks
"... This paper presents the design, implementation, and evaluation of EnviroMic, a novel distributed acoustic monitoring, storage, and trace retrieval system. Audio represents one of the least exploited modalities in sensor networks to date. The relatively high frequency and large size of audio traces m ..."
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Cited by 25 (1 self)
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This paper presents the design, implementation, and evaluation of EnviroMic, a novel distributed acoustic monitoring, storage, and trace retrieval system. Audio represents one of the least exploited modalities in sensor networks to date. The relatively high frequency and large size of audio traces motivate distributed algorithms for coordinating recording tasks, reducing redundancy of data stored by nearby sensors, filtering out silence, and balancing storage utilization in the network. Applications of acoustic monitoring with EnviroMic range from the study of mating rituals and social behavior of animals in the wild to audio surveillance of military targets. EnviroMic is designed for disconnected operation, where the luxury of having a basestation cannot be assumed. We implement the system on a TinyOS-based platform and systematically evaluate its performance through both indoor testbed experiments and a preliminary outdoor deployment. Results demonstrate up to a 4-fold improvement in effective storage capacity of the network compared to uncoordinated recording. Index Terms Sensor networks, applications, acoustics, distributed storage, group management
Secure range queries in tiered sensor networks
- in Proc. IEEE INFOCOM, 2009,pp
"... Abstract—We envision a two-tier sensor network which consists of resource-rich master nodes at the upper tier and resource-poor sensor nodes at the lower tier. Master nodes collect data from sensor nodes and answer the queries from the network owner. The reliance on master nodes for data storage and ..."
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Cited by 25 (6 self)
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Abstract—We envision a two-tier sensor network which consists of resource-rich master nodes at the upper tier and resource-poor sensor nodes at the lower tier. Master nodes collect data from sensor nodes and answer the queries from the network owner. The reliance on master nodes for data storage and query processing raises concerns about both data confidentiality and query-result correctness in hostile environments. In particular, a compromised master node may leak hosted sensitive data to the adversary; it may also return juggled or incomplete data in response to a query. This paper presents a novel spatiotemporal crosscheck approach to ensure secure range queries in event-driven two-tier sensor networks. It offers data confidentiality by preventing master nodes from reading hosted data and also enables efficient range-query processing. More importantly, it allows the network owner to verify with very high probability whether a query result is authentic and complete by examining the spatial and temporal relationships among the returned data. The high efficacy and efficiency of our approach are confirmed by detailed performance evaluations. I.
Envirostore: A cooperative storage system for disconnected operation in sensor networks
- In INFOCOM
, 2007
"... Abstract — This paper presents a new cooperative storage system for sensor networks geared for disconnected operation (where sensor nodes do not have a connected path to a basestation). The goal of the system is to maximize its data storage capacity by appropriately distributing storage utilization ..."
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Cited by 20 (1 self)
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Abstract — This paper presents a new cooperative storage system for sensor networks geared for disconnected operation (where sensor nodes do not have a connected path to a basestation). The goal of the system is to maximize its data storage capacity by appropriately distributing storage utilization and opportunistically offloading data to external devices when possible. The system is motivated by the observation that a large
Hyperion: High Volume Stream Archival for Retrospective Querying
, 2006
"... Network monitoring systems that support data archiving and after-the-fact (retrospective) queries are useful for a multitude of purposes, such as anomaly detection and network and security forensics. Data archiving for such systems, however, is complicated by (a) data arrival rates, which may be hun ..."
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Cited by 18 (1 self)
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Network monitoring systems that support data archiving and after-the-fact (retrospective) queries are useful for a multitude of purposes, such as anomaly detection and network and security forensics. Data archiving for such systems, however, is complicated by (a) data arrival rates, which may be hundreds of thousands of packets per second on a single link, and (b) the need for online indexing of this data to support retrospective queries. At these data rates, both common database index structures and general-purpose file systems perform poorly. This paper describes Hyperion, a system for archiving, indexing, and on-line retrieval of high-volume data streams. We employ a write-optimized stream file system for high-speed storage of simultaneous data streams, and a novel use of signature file indexes in a distributed multi-level index. We implement Hyperion on commodity hardware and conduct a detailed evaluation using synthetic data and real network traces. Our streaming file system, StreamFS, is shown to be fast enough to archive traces at over a million packets per second. The index allows queries over hours of data to complete in as little as 10-20 seconds, and the entire system is able to index and archive over 200,000 packets/sec while processing simultaneous on-line queries. 1
Secure multidimensional range queries in sensor networks
- In Proceedings of the ACM International Symposium on Mobile Ad Hoc Networking and Computing, Hong Kong
, 2009
"... Most future large-scale sensor networks are expected to follow a two-tier architecture which consists of resource-rich master nodes at the upper tier and resource-poor sensor nodes at the lower tier. Sensor nodes submit data to nearby master nodes which then an-swer the queries from the network owne ..."
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Cited by 18 (6 self)
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Most future large-scale sensor networks are expected to follow a two-tier architecture which consists of resource-rich master nodes at the upper tier and resource-poor sensor nodes at the lower tier. Sensor nodes submit data to nearby master nodes which then an-swer the queries from the network owner on behalf of sensor nodes. Relying on master nodes for data storage and query processing raises severe concerns about data confidentiality and query-result correctness when the sensor network is deployed in hostile environ-ments. In particular, a compromised master node may leak hosted sensitive data to the adversary; it may also return juggled or incom-plete query results to the network owner. This paper, for the first time in the literature, presents a suite of novel schemes to secure multidimensional range queries in tiered sensor networks. The pro-posed schemes can ensure data confidentiality against master nodes and also enable the network owner to verify with very high proba-bility the authenticity and completeness of any query result by in-specting the spatial and temporal relationships among the returned data. Detailed performance evaluations confirm the high efficacy and efficiency of the proposed schemes.
The Case for a Network Protocol Isolation Layer
"... Network protocols are typically designed and tested individually. In practice, however, applications use multiple protocols concurrently. This discrepancy can lead to failures from unanticipated interactions between protocols. In this paper, we argue that sensor network communication stacks should h ..."
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Cited by 16 (2 self)
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Network protocols are typically designed and tested individually. In practice, however, applications use multiple protocols concurrently. This discrepancy can lead to failures from unanticipated interactions between protocols. In this paper, we argue that sensor network communication stacks should have an isolation layer, whose purpose is to make each protocol’s perception of the wireless channel independent of what other protocols are running. We identify two key mechanisms the isolation layer must provide: shared collision avoidance and fair channel allocation. We present an example design of an isolation layer that builds on the existing algorithms of grant-to-send and fair queueing. However, the complexities of wireless make these mechanisms insufficient by themselves. We therefore propose two new mechanisms that address these limitations: channel decay and fair cancellation. Incorporating these new mechanisms reduces the increase in end-to-end delivery cost associated with concurrently operating two protocols by more than 60%. The isolation layer improves median protocol fairness from 0.52 to 0.96 in Jain’s fairness index. Together, these results show that using an isolation layer makes protocols more efficient and robust.
