22-10-2012, 02:06 PM
Service-Centric Framework for a Digital Government Application
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Abstract
This paper presents a service-oriented digital government infrastructure focused on efficiently providing customized
services to senior citizens. We designed and developed a Web Service Management System (WSMS), called WebSenior, which
provides a service-centric framework to deliver government services to senior citizens. The proposed WSMS manages the entire life
cycle of third-party web services. These act as proxies for real government services. Due to the specific requirements of our digital
government application, we focus on the following key components of WebSenior: service composition, service optimization, and
service privacy preservation. These components form the nucleus that achieves seamless cooperation among government agencies
to provide prompt and customized services to senior citizens.
INTRODUCTION
SERVICE-ORIENTED Computing (SOC) is a new and novel
paradigm that holds real promise to move the field of
computing from a data-centric to a service-centric view [20].
The simple and effective Service-Oriented Architecture
(SOA) has contributed greatly to the fast adoption of the
service paradigm [20]. The standardization frenzy that
ensued, while disorganized, has also galvanized the field
where the technology is now widely used. The flagship
technology and embodiment of service-oriented computing
is web services technology [30]. The introduction of web
services has been key to the wide and early adoption of
service-oriented computing in industry and lately in
government. In a nutshell, a web service is defined as a
functionality that can be programmatically accessible via
the web [25]. A fundamental objective of web services is to
enable interoperability among different software and data
applications running on a variety of platforms [30]. Web
services are increasingly being adopted to access data and
applications across the web [30]. This has been largely the
result of the many standardization efforts to describe,
advertise, discover, and invoke web services [22].
APPLICATION: SERVICES FOR SENIOR CITIZENS
In this section, we describe the environment and interactions
of our Digital Government application: WebSenior. The
major objective of the project is to provide an interoperable
infrastructure for the information systems of the VDA and
AAA, which is able to provide prompt and customized
service to senior citizens using the web.
The potential benefit of DG for senior citizens is of
particular interest for two reasons. First, the population
segment over 60 years old is growing dramatically in the
US, and seniors’ needs for assistance increase with age. It is
estimated that 31.2 percent of seniors age 80-84 require
assistance with everyday activities, including access to
health-related, social, and welfare programs. The percentage
increases to 49.5 percent for those over age 85 [13].
Second, seniors represent one of the fastest growing
segments of web users. To capitalize on this trend, many
federal, state, and local agencies now offer online forms to
access e-government services dedicated to seniors’ needs.
Unfortunately, such efforts have so far had little effect in the
lives of seniors in terms of their receiving better care and
services. Accessing public services poses bureaucratic
challenges that can be daunting in any case, but seniors
are challenged in ways that are fundamentally different
from other age groups. WebSenior is designed to automatically
deliver e-government services that are customized
for seniors.
Overview of VDA and AAA
VDA oversees all state programs using funds provided by
the federal Older Americans Act and the Virginia General
Assembly. VDA’s mission is to foster the dignity, independence,
and security of older Virginians by promoting
partnerships with families and communities. AAAs contract
with VDA to provide services for elder Virginians and their
families in communities throughout Virginia. The majority
of the VDA’s work come from managing these AAAs. This
includes managing the contracts, auditing them, providing
news and policy changes through a newsletter, and through
a monthly database upload to the VDA.
VDA and the 25 AAAs deploy their databases in great
variations. The 26 databases are from different vendors,
running on various platforms and storing data in different
formats. The VDA has adopted the Aging Information
Management (AIM) System to track and report the aging
service to the National Aging Program Information
System (NAPIS) annual reporting requirements. AAAs
collect data of services and store into their databases. At
the end of every month, officers in AAAs refine the data,
convert it into AIM compatible format, and send to VDA.
Fig. 1 depicts the data flow between six AAAs and VDA.
The potential data accuracy problem is illustrated in the
figure. Due to the data lost during conversion, the audit in
VDA found out many inaccuracies and missing or
incomplete information. Furthermore, coping with the
task of permanently monitoring the operation of the
25 AAAs is fairly expensive.
Service Optimization in WebSenior
The purpose of the service optimization component is to
select the best service(s) or their compositions to fulfill
senior citizens’ service requirements. Different service
providers (e.g., senior centers and transportation companies)
may compete to offer similar services. At the end of
the matchmaking algorithm described in last section,
multiple composition plans may be generated. These
composition plans offer the same functionality, but they
may be different in terms of the nonfunctional aspects. The
concept of Quality of Web Service (QoWS) is emerging as a
key feature in distinguishing between competing services.
QoWS reflects the runtime and business requirements of
web services, such as response time, availability, reliability,
cost, and reputation. For example, senior citizens may take
interest in the response time and the service reputation
when selecting a meal delivery service.
IMPLEMENTATION
Based on the architecture we described above, we organize
WebSenior into four tiers: user interaction management, service
management, service ontologies, and basic web services. The
key components of the user interaction management tier
are implemented using JSP/Servelet and deployed on a
Tomcat web server. The service management tier is
implemented using Java. The web services are developed
on Systinet WASP Server, which is a complete platform for
development, deployment, and management of webservice-
based applications. It is worth to note that the
ontologies are also implemented as web services and can
be accessed by using the same way as the basic services.
The architecture is illustrated in Fig. 5. Note that each
AAA has its own database storing the information of
services and all registered users, including senior citizens
and officers. Also, the service transactions are recorded in
the databases. VDA also has its own database, which
contains basic user information mainly used for authentication.
These databases are distributed on a set of Oracle 8i
servers. Note that the system can easily be extended by
adding other databases. New services can also be included
with minimum overhead by registering themselves with
the UDDI service registry.
RELATED WORK AND FUTURE TRENDS
Standards have so far been the key enablers of web services.
The intensive standardization support reflects the strong
industry backing of web services as a key mechanism for
deploying programmable functionalities on the web [30].
However, the field of web service research is fragmented
and still in its infancy. In this section, we discuss some work
that is most relevant to the WebSenior project and the
representative solutions. These include semantic web
service technologies, service optimization, service composition,
and some existing e-government web service projects.
We also put forward several research trends that would be
of significant importance for the future evolution of web
service technologies. These include change management of
composite services, web service mining, and M-Services.
DARPA Agent Markup Language-Service (DAML-S) is a
major effort aimed at enabling the semantic description of
web services (www.damlservices). However, DAML-S
gives little support for the business process semantics of
web services. For example, it does not allow the specification
of pre- and postoperations for automatically generating
composite services. Nor does it explicitly define notions of
behavior and business logic. The Web Service Modeling
Ontology describes various aspects related to Semantic web
services (www.wsmo.org). WSMO uses the Web Service
Modeling Framework as a starting point and refines it by
developing a formal ontology and language. Like DAML-S,
WSMO provides little or no support for specifying interoperational
relationships.
CONCLUSION
We describe a service-centric DG framework, WebSenior,
to provide services to senior citizens. We implemented
actual social services using web services as proxies. In this
context, WebSenior is a WSMS that manages the life cycle
of government social services. We have shown a set of
key service components in WebSenior, consisting of
service composition, optimization, and privacy preservation.
In particular, WebSenior provides mechanisms that
dynamically compose services, select service providers
based on their quality attributes, and enforce the privacy
of citizens when requesting and receiving government
services. One of our ongoing work is to perform extensive
experiments to assess the performance the proposed
WSMS and its key components.