Ives, Zachary

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Computer Sciences
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Assistant Professor
Introduction
Zachary Ives is an Assistant Professor at the University of Pennsylvania and an Associated Faculty Member of the Penn Center for Bioinformatics. He received his B.S. from Sonoma State University and his PhD from the University of Washington. His research interests include data integration, peer-to-peer models of data sharing, processing and security of heterogeneous sensor streams, and data exchange between autonomous systems. He is a recipient of the NSF CAREER award and a member of the DARPA Computer Science Study Panel.
Research Interests
Databases, data integration, peer-to-peer computing, sensor networks

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Now showing 1 - 9 of 9
  • Publication
    Recursive Computation of Regions and Connectivity in Networks
    (2008-10-31) Taylor, Nicholas E; Zhou, Wenchao; Ives, Zachary G; Liu, Mengmeng; Loo, Boon Thau
    In recent years, data management has begun to consider situations in which data access is closely tied to network routing and distributed acquisition: sensor networks, in which reachability and contiguous regions are of interest; declarative networking, in which shortest paths and reachability are key; distributed and peer-to-peer stream systems, in which we may monitor for associations among data at the distributed sources (e.g., transitive relationships). In each case, the fundamental operation is to maintain a view over dynamic network state; the view is frequently distributed, recursive and may contain aggregation, e.g., describing transitive connectivity, shortest paths, least costly paths, or region membership. Surprisingly, solutions to this problem are often domain-specific, expensive to compute, and incomplete. In this paper, we recast the problem as one of incremental recursive view maintenance in the presence of distributed streams of updates to tuples: new stream data becomes insert operations and tuple expirations become deletions. We develop a set of techniques that maintain information about tuple derivability—a compact form of data provenance. We complement this with techniques to reduce communication: aggregate selections to prune irrelevant aggregation tuples, provenance-aware operators that can determine when tuples are no longer derivable and remove them from their state, and shipping operators that greatly reduce the tuple and provenance information being propagated while still maintaining correct answers. We validate our work in a distributed setting with sensor and network router queries, showing significant gains in bandwidth consumption without sacrificing performance.
  • Publication
    MOSAIC: Multiple Overlay Selection and Intelligent Composition
    (2007-10-24) Loo, Boon Thau; Ives, Zachary G; Mao, Yun; Smith, Jonathan M
    Today, the most effective mechanism for remedying shortcomings of the Internet, or augmenting it with new networking capabilities, is to develop and deploy a new overlay network. This leads to the problem of multiple networking infrastructures, each with independent advantages, and each developed in isolation. A greatly preferable solution is to have a single infrastructure under which new overlays can be developed, deployed, selected, and combined according to application and administrator needs. MOSAIC is an extensible infrastructure that enables not only the specification of new overlay networks, but also dynamic selection and composition of such overlays. MOSAIC provides declarative networking: it uses a unified declarative language (Mozlog) and runtime system to enable specification of new overlay networks, as well as their composition in both the control and data planes. Importantly, it permits dynamic compositions with both existing overlay networks and legacy applications. This paper demonstrates the dynamic selection and composition capabilities of MOSAIC with a variety of declarative overlays: an indirection overlay that supports mobility (i3), a resilient overlay (RON), and a transport-layer proxy. Using a remarkably concise specification, MOSAIC provides the benefits of runtime composition to simultaneously deliver application-aware mobility, NAT traversal and reliability with low performance overhead, demonstrated with deployment and measurement on both a local cluster and the PlanetLab testbed.
  • Publication
    MOSAIC: Declarative Platform for Dynamic Overlay Composition
    (2012-05-27) Loo, Boon Thau; Ives, Zachary G; Mao, Yun; Smith, Jonathan M
    Overlay networks create new networking services using nodes that communicate using pre-existing networks. They are often optimized for specific applications and targeted at niche vertical domains, but lack interoperability with which their functionalities can be shared. MOSAIC is a declarative platform for constructing new overlay networks from multiple existing overlays, each possessing a subset of the desired new network’s characteristics. This paper focuses on the design and implementation of MOSAIC: composition and deployment of control and/or data plane functions of different overlay networks, dynamic compositions of overlay networks to meet changing application needs and network conditions, and seamless support for legacy applications. MOSAIC overlays are specified using Mozlog, a new declarative language for expressing overlay properties independently from their particular implementation or underlying network. MOSAIC is validated experimentally using compositions specified in Mozlog in order to create new overlay networks with compositions of their functions: the i3 indirection overlay that supports mobility, the resilient overlay network (RON) overlay for robust routing, and the Chord distributed hash table for scalable lookups. MOSAIC uses runtime composition to simultaneously deliver application-aware mobility, NAT traversal and reliability. We further demonstrate MOSAIC’s dynamic composition capabilities by Chord switching its underlay from IP to RON at runtime. MOSAIC’s benefits are obtained at a low performance cost, as demonstrated by measurements on both a local cluster environment and the PlanetLab global testbed.
  • Publication
    NetTrails: A Declarative Platform for Maintaining and Querying Provenance in Distributed Systems
    (2011-06-01) Zhuo, Wenchao; Fei, Qiong; Haeberlen, Andreas; Sun, Shengzhi; Ives, Zachary G; Tao, Tao; Loo, Boon Thau; Sherr, Micah
    We demonstrate NetTrails, a declarative platform for maintaining and interactively querying network provenance in a distributed system. Network provenance describes the history and derivations of network state that result from the execution of a distributed protocol. It has broad applicability in the management, diagnosis, and security analysis of networks. Our demonstration shows the use of NetTrails for maintaining and querying network provenance in a variety of distributed settings, ranging from declarative networks to unmodified legacy distributed systems. We conclude our demonstration with a discussion of our ongoing research on enhancing the query language and security guarantees.
  • Publication
    SmartCIS: Integrating Digital and Physical Environments
    (2010-01-01) Liu, Mengmeng; Mihaylov, Svilen; Ives, Zachary G; Bao, Zhuowei; Loo, Boon Thau; Jacob, Marie; Guha, Sudipto
  • Publication
    Recursive Computation of Regions and Connectivity in Networks
    (2009-03-29) Liu, Mengmeng; Taylor, Nicholas E; Zhou, Wenchao; Ives, Zachary G; Loo, Boon Thau
    In recent years, the data management community has begun to consider situations in which data access is closely tied to network routing and distributed acquisition: examples include, sensor networks that execute queries about reachable nodes or contiguous regions, declarative networks that maintain information about shortest paths and reachable endpoints, and distributed and peer-to-peer stream systems that detect associations (e.g., transitive relationships) among data at the distributed sources. In each case, the fundamental operation is to maintain a view over dynamic network state. This view is typically distributed, recursive, and may contain aggregation, e.g., describing transitive connectivity, shortest paths, least costly paths, or region membership. Surprisingly, solutions to computing such views are often domain-specific, expensive, and incomplete. In this paper, we recast the problem as one of incremental recursive view maintenance in the presence of distributed streams of updates to tuples: new stream data becomes insert operations and tuple expirations become deletions. We develop a set of techniques that maintain compact information about tuple derivability or data provenance. We complement this with techniques to reduce communication: aggregate selections to prune irrelevant aggregation tuples, provenance-aware operators that can determine when tuples are no longer derivable and remove them from their state, and shipping operators that greatly reduce the tuple and provenance information being propagated while still maintaining correct answers. We validate our work in a distributed setting with sensor and network router queries, showing significant gains in communication overhead without sacrificing performance.
  • Publication
    TAP: Time-Aware Provenance for Distributed Systems
    (2011-06-01) Haeberlen, Andreas; Zhuo, Wenchao; Ives, Zachary G; Ding, Ling; Loo, Boon Thau
    In this paper, we explore the use of provenance for analyzing execution dynamics in distributed systems. We argue that provenance could have significant practical benefits for system administrators, e.g., for reasoning about changes in a system’s state, diagnosing protocol misconfigurations, detecting intrusions, and pinpointing performance bottlenecks. However, to realize this vision, we must revisit several aspects of provenance management. As a first step, we present time-aware provenance (TAP), an enhanced provenance model that explicitly represents time, distributed state, and state changes. We outline our research agenda towards developing novel query processing, languages, and optimization techniques that can be used to efficiently and securely query time-aware provenance, even in the presence of transient state or untrusted nodes.
  • Publication
    Maintaining Recursive Views of Regions and Connectivity in Networks
    (2010-08-01) Liu, Mengmeng; Taylor, Nicholas E; Zhou, Wenchao; Ives, Zachary G; Loo, Boon Thau
    The data management community has recently begun to consider declarative network routing and distributed acquisition: e.g., sensor networks that execute queries about contiguous regions, declarative networks that maintain shortest paths, and distributed and peer-to-peer stream systems that detect transitive relationships among data at the distributed sources. In each case, the fundamental operation is to maintain a view over dynamic network state. This view is typically distributed, recursive, and may contain aggregation, e.g., describing shortest paths or least costly paths. Surprisingly, solutions to computing such views are often domain-specific, expensive, and incomplete. We recast the problem as incremental recursive view maintenance given distributed streams of updates to tuples: new stream data becomes insert operations and tuple expirations become deletions. We develop techniques to maintain compact information about tuple derivability or data provenance. We complement this with techniques to reduce communication: aggregate selections to prune irrelevant aggregation tuples, provenance-aware operators that determine when tuples are no longer derivable and remove them from the view, and shipping operators that reduce the information being propagated while still maintaining correct answers. We validate our work in a distributed setting with sensor and network router queries, showing significant gains in communication overhead without sacrificing performance.
  • Publication
    MOSAIC: Unified Platform for Dynamic Overlay Selection and Composition
    (2008-06-03) Mao, Yun; Loo, Boon Thau; Ives, Zachary G; Smith, Jonathan M
    MOSAIC constructs new overlay networks with desired characteristics by composing existing overlays with subsets of those attributes. Thus, MOSAIC overcomes the problem of multiple network infrastructures that are partial solutions, while preserving deployability. Composition of control and/or data planes is possible in the system. MOSAIC overlays are specified in Mozlog, a declarative language that specifies overlay properties without binding them to a particular implementation or underlying network. This paper focuses on the runtime aspects of MOSAIC: how it enables interoperability between different overlay networks and how it implements switching between different overlay compositions, permitting dynamic compositions with both existing overlay networks and legacy applications. The system is validated experimentally using declarative overlay compositions concisely specified in Mozlog: an indirection overlay that supports mobility (i3), a resilient overlay (RON), and scalable lookups (Chord), all of which are combined to provide new functionality. MOSAIC provides the benefits of runtime composition to simultaneously deliver application-aware mobility, NAT traversal and reliability with low performance overhead, demonstrated by measurements on both a local cluster and PlanetLab.