Testing Synchronous Systems through Anti-Extension

Speaker:	Dr. Wing Kwong CHAN
		Department of Computer Science
		The Hong Kong University of Science and Technology

Title:		"Testing Synchronous Systems through Anti-Extension"

Date:		Monday, 3 April 2006

Time:		4:00pm - 5:00pm

Venue:		Lecture Theatre F
		(Leung Yat Sing Lecture Theatre, near lift nos. 25/26)
		HKUST

ABSTRACT:

Concurrent software is a popular paradigm for ubiquitous computing, which
is typically context-aware, embedded and trust-worthy in nature. Rigorous
testing of such systems is indispensable. Nevertheless, the
state-explosion problem, in which the size of a system grows exponentially
with the number of sequential or concurrent modules, is a severe obstacle
to the generation of test cases for concurrent systems. Most existing
techniques sidestep the problem by ignoring the fact that a module is made
up of sub-modules. To ease the testing of collaboration of modules, they
seldom consider a concurrent module to be decomposable. My study shows
that there are non-trivial problems in generating test cases compositely.

In this talk, I shall present a key criterion to assure the conformity of
test cases for concurrent systems. I stipulate it in Communicating
Sequential Processes (CSP), which is an excellent tool for modeling these
systems. A process is the behavior pattern of an object. A concurrent
system is modeled as processes that may be composed sequentially and
concurrently. The presented work supports both process composition and
abstraction. It decomposes a given process into sequential compositions of
component processes. Each component can be anti-extended into abstract
forms. Sequential and concurrent combinations of abstract forms can
substitute their corresponding components in a process to give aggregated
abstract forms. Since the given processes, components, and abstract forms
are all processes, this approach can be applied compositely and
recursively. Mathematical theorems assure that these aggregated abstract
processes are anti-extensions of the corresponding processes under
well-specified necessary and sufficient conditions. Hence, test cases
generated from these processes will be conformance test cases for the
implementations. I apply the results to the testing of context-aware
middleware-based systems via control flow graphs, which are mathematically
sound abstractions of the original implementation under test. These
control flow graphs are augmented with data flow edges to facilitate the
generation of context-oriented test cases. At the close of my talk, I
shall present the experimental results on a comparison of our work with
existing approaches.



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Biography:

Wing-Kwong Chan is a post-doctorate fellow of the Department of Computer
Science, The Hong Kong University of Science and Technology He received
his Ph.D, M.Phil., and B.Eng (Computer Engineering) degrees, all from The
University of Hong Kong, in 2004, 1995, and 1993, respectively. His
research interests include software testing, verification, and pervasive
computing. He was a software engineer before returning to The University
of Hong Kong to complete his Ph.D degree. He was with Oracle Consultant,
Lane Crawford, HKU Computer Centre, and HKU SPACE to develop enterprise
systems and implement Oracle Financials.