8,353 research outputs found
Experimental Performance Evaluation of Cloud-Based Analytics-as-a-Service
An increasing number of Analytics-as-a-Service solutions has recently seen
the light, in the landscape of cloud-based services. These services allow
flexible composition of compute and storage components, that create powerful
data ingestion and processing pipelines. This work is a first attempt at an
experimental evaluation of analytic application performance executed using a
wide range of storage service configurations. We present an intuitive notion of
data locality, that we use as a proxy to rank different service compositions in
terms of expected performance. Through an empirical analysis, we dissect the
performance achieved by analytic workloads and unveil problems due to the
impedance mismatch that arise in some configurations. Our work paves the way to
a better understanding of modern cloud-based analytic services and their
performance, both for its end-users and their providers.Comment: Longer version of the paper in Submission at IEEE CLOUD'1
Spying the World from your Laptop -- Identifying and Profiling Content Providers and Big Downloaders in BitTorrent
This paper presents a set of exploits an adversary can use to continuously
spy on most BitTorrent users of the Internet from a single machine and for a
long period of time. Using these exploits for a period of 103 days, we
collected 148 million IPs downloading 2 billion copies of contents. We identify
the IP address of the content providers for 70% of the BitTorrent contents we
spied on. We show that a few content providers inject most contents into
BitTorrent and that those content providers are located in foreign data
centers. We also show that an adversary can compromise the privacy of any peer
in BitTorrent and identify the big downloaders that we define as the peers who
subscribe to a large number of contents. This infringement on users' privacy
poses a significant impediment to the legal adoption of BitTorrent
A Literature Survey of Cooperative Caching in Content Distribution Networks
Content distribution networks (CDNs) which serve to deliver web objects
(e.g., documents, applications, music and video, etc.) have seen tremendous
growth since its emergence. To minimize the retrieving delay experienced by a
user with a request for a web object, caching strategies are often applied -
contents are replicated at edges of the network which is closer to the user
such that the network distance between the user and the object is reduced. In
this literature survey, evolution of caching is studied. A recent research
paper [15] in the field of large-scale caching for CDN was chosen to be the
anchor paper which serves as a guide to the topic. Research studies after and
relevant to the anchor paper are also analyzed to better evaluate the
statements and results of the anchor paper and more importantly, to obtain an
unbiased view of the large scale collaborate caching systems as a whole.Comment: 5 pages, 5 figure
On-Demand Big Data Integration: A Hybrid ETL Approach for Reproducible Scientific Research
Scientific research requires access, analysis, and sharing of data that is
distributed across various heterogeneous data sources at the scale of the
Internet. An eager ETL process constructs an integrated data repository as its
first step, integrating and loading data in its entirety from the data sources.
The bootstrapping of this process is not efficient for scientific research that
requires access to data from very large and typically numerous distributed data
sources. a lazy ETL process loads only the metadata, but still eagerly. Lazy
ETL is faster in bootstrapping. However, queries on the integrated data
repository of eager ETL perform faster, due to the availability of the entire
data beforehand.
In this paper, we propose a novel ETL approach for scientific data
integration, as a hybrid of eager and lazy ETL approaches, and applied both to
data as well as metadata. This way, Hybrid ETL supports incremental integration
and loading of metadata and data from the data sources. We incorporate a
human-in-the-loop approach, to enhance the hybrid ETL, with selective data
integration driven by the user queries and sharing of integrated data between
users. We implement our hybrid ETL approach in a prototype platform, Obidos,
and evaluate it in the context of data sharing for medical research. Obidos
outperforms both the eager ETL and lazy ETL approaches, for scientific research
data integration and sharing, through its selective loading of data and
metadata, while storing the integrated data in a scalable integrated data
repository.Comment: Pre-print Submitted to the DMAH Special Issue of the Springer DAPD
Journa
On Constructing Persistent Identifiers with Persistent Resolution Targets
Persistent Identifiers (PID) are the foundation referencing digital assets in
scientific publications, books, and digital repositories. In its realization,
PIDs contain metadata and resolving targets in form of URLs that point to data
sets located on the network. In contrast to PIDs, the target URLs are typically
changing over time; thus, PIDs need continuous maintenance -- an effort that is
increasing tremendously with the advancement of e-Science and the advent of the
Internet-of-Things (IoT). Nowadays, billions of sensors and data sets are
subject of PID assignment. This paper presents a new approach of embedding
location independent targets into PIDs that allows the creation of
maintenance-free PIDs using content-centric network technology and overlay
networks. For proving the validity of the presented approach, the Handle PID
System is used in conjunction with Magnet Link access information encoding,
state-of-the-art decentralized data distribution with BitTorrent, and Named
Data Networking (NDN) as location-independent data access technology for
networks. Contrasting existing approaches, no green-field implementation of PID
or major modifications of the Handle System is required to enable
location-independent data dissemination with maintenance-free PIDs.Comment: Published IEEE paper of the FedCSIS 2016 (SoFAST-WS'16) conference,
11.-14. September 2016, Gdansk, Poland. Also available online:
http://ieeexplore.ieee.org/document/7733372
HoPP: Robust and Resilient Publish-Subscribe for an Information-Centric Internet of Things
This paper revisits NDN deployment in the IoT with a special focus on the
interaction of sensors and actuators. Such scenarios require high
responsiveness and limited control state at the constrained nodes. We argue
that the NDN request-response pattern which prevents data push is vital for IoT
networks. We contribute HoP-and-Pull (HoPP), a robust publish-subscribe scheme
for typical IoT scenarios that targets IoT networks consisting of hundreds of
resource constrained devices at intermittent connectivity. Our approach limits
the FIB tables to a minimum and naturally supports mobility, temporary network
partitioning, data aggregation and near real-time reactivity. We experimentally
evaluate the protocol in a real-world deployment using the IoT-Lab testbed with
varying numbers of constrained devices, each wirelessly interconnected via IEEE
802.15.4 LowPANs. Implementations are built on CCN-lite with RIOT and support
experiments using various single- and multi-hop scenarios
Basis Token Consistency: A Practical Mechanism for Strong Web Cache Consistency
With web caching and cache-related services like CDNs and edge services playing an increasingly significant role in the modern internet, the problem of the weak consistency and coherence provisions in current web protocols is becoming increasingly significant and drawing the attention of the standards community [LCD01]. Toward this end, we present definitions of consistency and coherence for web-like environments, that is, distributed client-server information systems where the semantics of interactions with resource are more general than the read/write operations found in memory hierarchies and distributed file systems. We then present a brief review of proposed mechanisms which strengthen the consistency of caches in the web, focusing upon their conceptual contributions and their weaknesses in real-world practice. These insights motivate a new mechanism, which we call "Basis Token Consistency" or BTC; when implemented at the server, this mechanism allows any client (independent of the presence and conformity of any intermediaries) to maintain a self-consistent view of the server's state. This is accomplished by annotating responses with additional per-resource application information which allows client caches to recognize the obsolescence of currently cached entities and identify responses from other caches which are already stale in light of what has already been seen. The mechanism requires no deviation from the existing client-server communication model, and does not require servers to maintain any additional per-client state. We discuss how our mechanism could be integrated into a fragment-assembling Content Management System (CMS), and present a simulation-driven performance comparison between the BTC algorithm and the use of the Time-To-Live (TTL) heuristic.National Science Foundation (ANI-9986397, ANI-0095988
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