The Piazza peer data management project

Tatarinov, Igor; Madhavan, Jayant; Halevy, Alon; Suciu, Dan; Dalvi, Nilesh; Dong, Xin Luna; Kadiyska, Yana; Miklau, Gerome; Mork, Peter

doi:10.1145/945721.945732

Cited by 138 publications

(80 citation statements)

References 19 publications

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“…Local-as-view approaches are considered in a number of P2P data management systems, e.g., Piazza [29] that also consider richer mappings to specify views. Update propagation between views is considered in a number of systems, e.g., based on ECA rules in Hyperion [8].…”

Section: Related Workmentioning

confidence: 99%

Explanations and Transparency in Collaborative Workflows

Abiteboul

Bourhis

Vianu

2018

Proceedings of the 37th ACM SIGMOD-SIGACT-SIGAI Symposium on Principles of Database Systems

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We pursue an investigation of data-driven collaborative workflows. In the model, peers can access and update local data, causing side-e↵ects on other peers' data. In this paper, we study means of explaining to a peer her local view of a global run, both at runtime and statically. We consider the notion of "scenario for a given peer" that is a subrun observationally equivalent to the original run for that peer. Because such a scenario can sometimes di↵er significantly from what happens in the actual run, thus providing a misleading explanation, we introduce and study a faithfulness requirement that ensures closer adherence to the global run. We show that there is a unique minimal faithful scenario, that explains what is happening in the global run by extracting only the portion relevant to the peer.With regard to static explanations, we consider the problem of synthesizing, for each peer, a "view program" whose runs generate exactly the peer's observations of the global runs. Assuming some conditions desirable in their own right, namely transparency and boundedness, we show that such a view program exists and can be synthesized. As an added benefit, the view program rules provide provenance information for the updates observed by the peer.

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Section: Related Workmentioning

confidence: 99%

Explanations and Transparency in Collaborative Workflows

Abiteboul

Bourhis

Vianu

2018

Proceedings of the 37th ACM SIGMOD-SIGACT-SIGAI Symposium on Principles of Database Systems

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“…The typical PDMS includes Edutella [4], Piazza [5], PeerDB [6], PIER [7], GridVine [8], etc. Edutella is a JXTA-based super peer PDMS.…”

Section: Related Workmentioning

confidence: 99%

An Effective Schema Mapping Model for Decentralized Network

Wang¹,

Shen²,

Yu³

2015

Advances in Social Science, Education and Humanities Research

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Abstract. Schema heterogeneity among individual peers is an important issue in PDMS (Peer Data Management System). Schema mapping is a key technology to find the semantic matching relationship between schemas, and it plays an important role in PDMS. In this paper, we address the problem of schema mapping in PDMS, a typical decentralized network. Aiming at the limitations of previous methods, we propose a schema mapping model based on peer interest, schema structure information and query log, and we also considers the uncertainty of schema mapping during query propagation among peers. In our model, the peers with same interest organize a community and the schema mapping is handled in the interest community. We propose a query processing strategy in which the uncertainty of schema mapping in taken into account. In order to supplement the matching and reasoning, we mine the query log to discover the relationship between schema elements and refine the schema mapping further. Experimental results show that our method is feasible and effective for schema mapping in decentralized network.

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“…We create mappings between pairs of schemas to link semantically related vocabulary terms. Mappings are used to identify equivalent terms in the data propagation process (see below Section 4.4), and to reformulate queries iteratively as in a peer data management system [2,32].…”

Section: Dealing With Metadata Heterogeneity Through Pairwise Schema mentioning

confidence: 99%

“…PDMSs integrate data by replacing the cen-tralized mediator by an unstructured network of pairwise schema mappings and by reformulating the queries iteratively from one schema to the others. The complexity of query reformulation in PDMSs is investigated in the context of the Piazza [32] project, while the Hyperion [2] system proposes to use mappings at both the instance and at the schema levels to reformulate queries. PicShark is the first PDMS taking into account probabilistic tuples and supporting the propagation of instances from one database to the others through schema mappings.…”

Section: Related Workmentioning

confidence: 99%

PicShark: mitigating metadata scarcity through large-scale P2P collaboration

et al. 2008

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With the commoditization of digital devices, personal information and media sharing is becoming a key application on the pervasive Web. In such a context, data annotation rather than data production is the main bottleneck. Metadata scarcity represents a major obstacle preventing efficient information processing in large and heterogeneous communities. However, social communities also open the door to new possibilities for addressing local metadata scarcity by taking advantage of global collections of resources. We propose to tackle the lack of metadata in large-scale distributed systems through a collaborative process leveraging on both content and metadata. We develop a community-based and self-organizing system called PicShark in which information entropy -in terms of missing metadatais gradually alleviated through decentralized instance and schema matching. Our approach focuses on semistructured metadata and confines computationally expensive operations to the edge of the network, while keeping distributed operations as simple as possible to ensure scalability. PicShark builds on structured Peer-to-Peer networks for distributed look-up operations, but extends the application of self-organization principles to the propagation of metadata and the creation of schema mappings. We demonstrate the practical applicability of our method in an image sharing scenario and provide experimental evidences illustrating the validity of our approach.

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The Piazza peer data management project

Cited by 138 publications

References 19 publications

Explanations and Transparency in Collaborative Workflows

Explanations and Transparency in Collaborative Workflows

An Effective Schema Mapping Model for Decentralized Network

PicShark: mitigating metadata scarcity through large-scale P2P collaboration

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