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Distributed Composition Services for Self-
adaptation Wireless Sensor Networks
Lei Zhang, Maode Ma, Gang Zhang
College of Computer Sci & Tech, Tianjin University
Tianjin, China
lzhang@tju.edu.cn, emdma@ntu.edu.sg, gzhang@tju.edu.cn
Alvin S Lim
Depart of Computer Science, Auburn University
Auburn, AL, USA
lim@eng.auburn.edu
Abstract
—
The heterogeneity and mobility inherent in a
large-scale wireless sensor network makes it difficult to
develop different applications. The difficulty primarily
arises from weak and intermittent connections, dynamic
reconfiguration, and limited power availability. The
challenge in building a distributed service adaptive to
environmental changes lies in the degree of data
transmission and the adaptation to the dynamics can be
automated or transparent to applications. Most
applications in wireless sensor networks involve a group of
nodes coordinating to perform one task. Distributed
composition service enables data centric nodes to form a
dynamic task group and maintain the group. In this paper,
we demonstrate the composition service and its
implementation and show that the re-organization process
can be automated in collaboration with the composition
service by an adaptation server. Our testing validates the
framework of the composition service and the
performance improvement.
Keywords
—distributed services, composition service,
wireless sensor networks, self-adaptation
I. I
NTRODUCTION
Many dynamic systems must be controlled by adaptive
methods that utilize critical and real-time data gathered from
many sensor devices [1-3]. These sensors nodes are connected
in an ad-hoc fashion collecting and processing data in a
distributed way. However, these smart sensor nodes have
some inherent limitations such as node mobility, resources
constrained and prone to failure, which make wireless sensor
network (WSN) research challenging.
Till now, a lot of the WSN research work focuses on
developing platforms and protocols such as the hardware and
system developments reported in [4-5]. However, the
heterogeneous nature of the development environments is a
big block to the system developments. Software is always
produced over a particular platform, while it is hardly ported
to other different hardware or operating systems. The system
developers have to design the low-level system details
adaptive to specific upper layer protocols. Thus, a systematic
framework that provides developers with a conceptual view of
the networks and hides lower layers details is necessary.
The ideas of the distributed service layer, on which other
networking services could be spontaneously specified and re-
configured have been addressed in [1, 6-8]. All these services
are designed to simplify and facilitate the application
developments and to help the network adaptive to the
dynamics, such as node failure and mobility.
As proposed in [4-5], the directed diffusion is a
distributed routing protocol with routing decisions made
according to the data requested. One of the most significant
issues of the directed diffusion is the packet flooding. The
region filter developed in [9] is an improvement to the
directed diffusion. It maintains message re-transmission
mechanisms within a specific region and filters out some
traffic in the networks.
The other important issue of directed diffusion is node
failure treatment. There are some mechanisms responding to
node failure built in the directed diffusion. When data stop
arriving at one node due to its upstream node going down,
directed diffusion will trigger the event of flooding similar
interest packets in the entire network. This basic form of
adaptability is adequate for simple query-response systems,
but not sufficient for complex applications due to long delay
required to find a replacement, network flooding and the
undetermined physical location of the substitution.
Additionally, the task of reconfiguring the upstream nodes,
which will introduce extra low-level system details adaptive
to directed diffusion at the upper layer cannot be effectively
achieved.
In this research, based on the idea of distributed services
introduced in [1, 6-8] and the issues of directed diffusion
routing protocol in [4-5], we aim to achieve the following
goals:
• To design and implement Application Programming
Interface (APIs) for the distributed composition services.
• To maintain the normal networking functionalities under
abnormal networking conditions with the helps of
distributed services.
The remaining of the paper is organized as follows.
Section 2 presents some technologies related to the distributed
composition service. Section 3 discusses the architecture of
one distributed service and the composition service with its
APIs. The performance of the distributed composition service
is evaluated in Section 4. Section 5 draws the conclusion by
summarizing the research work.
II. RELATED WORK
This work is supported in part by NSF China under grants No. 61202379,