CROWN: A Service Grid Middleware for e-Science - Grid Computing: Infrastructure, Service, and Applications - page 4

in China, such as the National University of Defense Technology of China
(NUDT), Peking University, the Computer Network Information Center of
China Academy of Science (CNIC, CAS), and Tsinghua University. The out-
put of the CROWN project falls into three parts: the middleware, set to build
a service-oriented grid system; the testbed to enable the evaluation and
verii cation of grid-related technologies; and the applications.
The CROWN service grid middleware is the kernel for building an
application service grid. The basic features of CROWN are listed as
follows: i rst, it adopts an Open Grid Services Architecture/Web Services
Resource Framework (OGSA/WSRF) compatible architecture [2]; second,
considering the application requirements and the limitations of the secu-
rity architecture of OGSA/WSRF, more focus is put on the grid resource
management and dynamic management mechanism in the design stage,
and a new security architecture with a distributed access control mecha-
nism and trust management mechanism, which are proposed to support
the sharing and collaborating of resources in a loosely coupled environ-
ment, is proposed in CROWN.
Under the framework of the CROWN project, we also created the CROWN
testbed, integrating 41 high-performance servers or clusters distributed
among 11 institutes in 5 cities (as of April 2007). They are logically arranged
in 16 domains of 5 regions by using the CROWN middleware. The testing
environment is growing continuously and has become very similar to the
real production environment. The CROWN testbed will eventually evolve
into a wide-area grid environment for both research and production.
CROWN has become one of the important e-Science infrastructures in
China. We have developed and deployed a series of applications from dif-
ferent disciplines, which include the Advanced Regional Eta-coordinate
Numerical Prediction Model (AREM), the Massive Multimedia Data
Processing Platform (MDP), gViz for visualizing the temperature i eld of
blood l ow [3], the Scientii c Data Grid (SDG), and the Digital Sky Survey
Retrieval (DSSR) for virtual observation. These applications are used as
test cases to verify the technologies in CROWN.

1.2 CROWN Middleware

1.2.1 Design Motivation

Since many researchers are focusing on technologies and applications of
grids, the interoperability and loosely coupled integration problem between
different grid systems are now becoming a hot topic. At the same time, the
application and standardization of Web services technology are developing
rapidly, and service-oriented architectures (SOAs) have become an impor-
tant trend in building a distributed computing environment for wide-area