Analysis and Verification of Component
Behavior Equivalence for ScudWare Middleware
in Ubiquitous Computing Environments
Qing Wu, Chunbo Zhao
College of Computer Science, Hangzhou Dianzi University
Email: wuqing@hdu.edu.cn
Ying Li
Zhejiang University
College of Computer Science
Email: cnliying@zju.edu.cn
Abstract— In ubiquitous computing environments, the soft-
ware component model with semantic information and
behavior adaptation to satisfy various resources constraints
and component interdependence is needed. It is an im-
portant issue to analyze the behavioral equivalence of
components when studying the dynamic replacement and
recombination of them. However it is difficult to check the
equivalence of behaviors rapidly and precisely. In order
to improve the precision of judging, and guarantee the
normality and stability of system after replacing and re-
combining components for adaptation in system, the paper
uses and extends the theories of equivalence analysis in π
calculus, then puts forward some formalizations. After that
we make some examples in detail to model the behaviors
of components based on higher-order typed π calculus
and analyze the equivalence of them. At last, the mobility
workbench is used to make verification of this equivalence.
Index Terms— adaptive middleware; semantic component;
component behavior equivalence.
I. INTRODUCTION
Driven by the expansion of the network and the desire
for mobility, today’s computations are becoming more
ubiquitous and embedded [1]. It provides more facilities
and comfort for our life. Ubiquitous computing aims at
fusing physical world and information space naturally
and seamlessly, which demands plenty of computation
resources for performance requirements. It must require
considering interdependences of functional aspects. How-
ever, the computation resources in ubiquitous and embed-
ded environments are limited such as CPU computation
capabilities, network bandwidth, and memory size. As
a result, it sometime cannot provide enough resources
to execute some applications successfully. In addition,
changes of the heterogeneous contexts including people,
computing devices and environments are ubiquitous, de-
manding that distributed software be able to adapt to
This paper is based on “A Semantic Component Model for Adaptive
Middleware in Ubiquitous Computing Environments,” by Wu Qing,
and Li Ying, which appeared in the Proceedings of the Second In-
ternational Workshop on Computer Science and Engineering, 28-30
Oct.2009,Qingdao, China.
c
° 2009 IEEE.
This work was supported by National Natural Science Foundation of
China under Grant No. 60703088.
these changes. Therefore, it results in many problems
in software design and development. We think software
adaptation is the key issue of the systems to meet the
different computing environments.
Software adaptation may require recomposition of
functional aspects, which realize the imperative behavior
of an application, and nonfunctional aspects, such as
QoS, fault tolerance and security [2]. Specially, it attracts
much attention on making research on component-based
software architecture, in which replacing and recombinant
of component has become one of the most attractive
topics to realize software adaptation. In order to ensure
the stability and reliability of the whole system, we have
to analyze the behavioral equivalence of new component
and replaced component.
Component behavior equivalence requires not merely
interface matching, but consistency of function behavior.
Some researchers neglect the function behavior and this
leads to the one-sidedness of research results. Some
others have used interface automata to model component
behavior flow [3], [4], those behaviors having same action
sequence is considered as equal. However, when one
flow has more then one action sequence, the respec-
tively equivalence of each sequence doesn’t mean the
equivalence of the whole flow. Thus the accuracy isn’t
high enough. Besides, process algebra bisimulation theory
[5], [6] has also been applied to analyze the behavior
equivalence. Nevertheless, no standard has been made for
analyzing the component interactive behavior equivalence
[7]–[9], meanwhile the one-sidedness and inaccuracy still
exist. Aiming at these problems, this paper extends the
bisimulation theory of π calculus, uses higher-order typed
π calculus to formalized model and analyze equivalence,
then apply a tool of mobility workbench to verify the
results.
The remainder of the paper is organized as follows.
First, we present a ScudWare middleare platform in sec-
tion 2. Section 3 describes how to use higher-order typed
π calculus to formalized express semantic component
model and its dynamic behaviors. In section 4, we firstly
propose some theories on behavioral equivalence and the
JOURNAL OF SOFTWARE, VOL. 5, NO. 8, AUGUST 2010 883
© 2010 ACADEMY PUBLISHER
doi:10.4304/jsw.5.8.883-890