of-service metrics of Io T services. Another potential approach could reuse
the solution of the Web by constructing a network of hidden links between
Io T things23, 24 and applying link analysis algorithms such as Page Rank and
its variants to devise a natural ordering
of content in the Io T.
Security, privacy, trust. IoTSE instances have the potential to detect
and retrieve anything in the IoT, at
any place and any time. They bring a
wide range of benefits to human users
and software agents but also present
significant security and privacy risks.
Io TSE instances can track a person,
monitor an area without consent, 4
and spy into warehouses of competing businesses. 3 Perpetrators can also
take advantage of IoTSE to propagate malicious sensing information
and actuating services. As future Io T
applications might rely solely on IoTSE to acquire IoT content for their
operation, misleading information
propagated by Io TSE can have severe
impacts. For example, by planting
sensors that imply a restaurant is full,
competitors can drive it out of business. Addressing security, privacy,
and trust issues, therefore, is arguably
more critical to the success and adoption of Io TSE compared to perfecting
its discovery and search algorithms.
Facilitating composition and reuse of IoTSE solution. Across different classes of Io TSE, we have observed
shared internal operations such as
content discovery, indexing, and
searching, albeit with different implementation to serve different types of
Io T content. We have also observed the
overlaps between various meta-paths,
such as between [D + R → T → R] and
[D → T → R]. These observations suggest that prior IoTSE instances can be
reused to improve other instances or
compose new instances, which might
utilize a different meta-path.
Realizing composition and reuse
of Io TSE solutions require a common
Io TSE architecture and a supporting
software infrastructure to support the
development, accumulation of Io TSE
components, and the engineering of
IoTSE instances from those compo-
nents. Tran et al. 19 propose to utilize
a shared software library to facilitate
the development of reusable, compos-
able Io TSE components and support
the composition of these components
into operational Io TSE instances. Re-
ducing the constraints of the shared
library on component developers and
simplifying the distribution of com-
ponents in an IoTSE instance could
improve the approach. The Service-
oriented Architecture (SOA) is a po-
tential solution to this problem, due
to its enforced separation of concern
between services and its native sup-
port for composition.
Internet of Things Search Engine denotes a software system responsible
for discovering and resolving queries
on contents of the Internet of Things.
Due to the diversity of IoT contents,
developing IoTSE is a complex and
diverse problem that is still relatively
immature. This article introduces
concepts, models, and a classification
system for IoTSE, which have been
generated from a structured and comprehensive study of the literature on
Io TSE. We have categorized the latest
works into eight classes of Io TSE and
presented four major open issues that
impact all classes of Io TSE.
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Nguyen Khoi Tran is a researcher at the University of
Adelaide, South Australia.
Quan Z. Sheng is a professor at Macquarie University,
M. Ali Babar is a professor at the University of Adelaide,
Lina Yao is a senior lecturerat the University of New
South Wales, Sydney, Australia.
Wei Emma Zhang is a lecturer at the University of
Adelaide, South Australia.
Schahram Dustdar is a professor at TU Wien, Austria.
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