A SOA-BASED SYSTEM INTERFACE CONTROL FOR

E-GOVERNMENT

Namho Yoo, Hyeong-Ah Choi

Department of Computer Science, The George Washington University,

801 22

Street, N.W., Room 730, Washington, DC 20052, USA

Keywords: Service-Oriented Architecture (SOA), XML, System Engineering, Interface Control, XPath, E-Government.

Abstract: In this paper, a SOA-based system approach is presented for system interface control in sustained systems.

Once a system is completed developed, it goes into a sustained phase supported by many interfaces. As

new technologies develop, updating and maintaining such systems require non-trivial efforts. A clear pre-

requisite before the deployment of a new system is to clarify the influence of changes on other systems

connected through interfaces. However, as each sustained system manages its own information separately,

integrating relevant information among the interfaced systems is a major hurdle to build SOA in E-Gov.

Therefore, the XML technology is applied to support system interface control toward SOA using step-by-

step approach in E-Government. In particular, I focus on messaging interface issues in Health Level Seven

typically used in medical information system and propose SOA framework cube and a scheme to represent

message information that can be used for the decision support of interface impact between sustained

systems.

1 INTRODUCTION

For E-government, Service Oriented Architecture

(SOA) is a new paradigm and driving force for

developing and integrating multiple systems. SOA

is an approach for building distributed systems that

deliver application functionality as services to end-

user applications or are used for building other

services.(Duermeyer, 2005) As the components of

E-Government are diverse containing multiple

vendors systems deployed, system engineering

efforts toward SOA are necessary for not only

internal factor but also externally used. It is

expected that many E-Government system being

migrated into web-enabled services. Since system

environments change rapidly and engineering

change efforts for interface control are increasingly

significant, many documentation associated with E-

government is considered to carefully examine in

terms of non-functional view as well as functional

perspective.

Overall, for SOA, an architectural style between

components is loosely coupled. Since the key of E-

Government are document-oriented designed, the

exchange between each components based on E-

Government document should be standardized.

Interface Control Document (ICD), which is one

of the key documentation for configuration

management for interface change, contains the

description about exchanging requirement and

concept of operation between interfacing system and

Figure 1: SOA-

ased System Interface Control

Framework Cube.

Enterprise Decision Making

Application Migration

Policy and Governance

Document-Oriented Modeling

Collaboration(standard/industry)

cal

Compos able

Reusable

Loosely Coupled

E-Gov Issues

SOA Requirement

act

242

Yoo N. and Choi H. (2006).

A SOA-BASED SYSTEM INTERFACE CONTROL FOR E-GOVERNMENT.

In Proceedings of the Eighth International Conference on Enterprise Information Systems - ISAS, pages 242-245

DOI: 10.5220/0002457302420245

 SciTePress

how they should be implemented and maintained

(MIL, 2004). The proposed approach, therefore, is

the SOA-based framework of for system interface

control using XML, which is one of standard for

exchanging information like Figure 1.

This paper suggests an effective process and

method to consider interface control requirement

while migrating multiple applications toward SOA-

based environment. For dealing with the interface

control, SOA-based metrics approach for interface

control analysis is discussed and prototyping

environment for testing is also suggested as a

lightweight tool. In order to figure interface control

requirement out, Engineering Change Proposal

(ECP), which is common vehicle of configuration in

E-Gov is addressed as an exchanging the change

(Yoo, 2004)

Furthermore, since there is system resource

information without specification, common vehicle

to exchange information effectively is required. In

this paper, Extensible Markup Language (XML)

technology is used for supporting engineering

change efforts for impact analysis. An XML is

widely used as a standard for information exchange

on the World Wide Web.(W3C, 2000)

2 BACKGROUND

In the past, it is shown that E-government

capabilities for communication are email,

conference call and discussion board (such as

bulletin board system). But these tendencies are

being moved to web services and effectively

collaborative way to interacting with customers.

Under considering an world-wide deployed US

health system involving 8 sub-systems A through H

with more than 50 to 200 sites, a impact analysis for

interface control is essential for decision-

making.(Yoo, 2005).

In case that current E-Gov systems are connected

each other, the change of specific system for

migrating the SOA affects other systems connected

(Duermeyer, 2005). Therefore, enterprise-level

planning for the application migration is necessary

to reduce conflicts and negative side effect and to

increase efficiency and effectiveness. It is essential

for enterprise-level planning to analyze current

status based on system documentation as an input.

E-Gov systems has contains Government off the

shelf (GOTS) with sustained phase. These systems

had developed diverse level of documentation

baseline while maintaining system. Because of

limited budget, to invest the workload for

standardized documentation baseline is difficult.

Furthermore, as each system change toward the

SOA purpose has different requirement and timeline,

the process with considering system interoperability

under SOA should be considered (Duermeyer,

2005).

Moreover, consider the interface between

systems A and B. The Health Level Seven (HL7)

protocol messaging supported by the interface

engine between A and B is given in Figure 2 as an

example.

In table 1, the several cases of system for

checking status with priority toward the SOA are

presented. In priority (1-5), there is various factors

to represent system status to migrate SOA. But the

analysis result is dependent to Subject Matter Export

(SME)’s knowledge and experience. And there are

many cases existed not for sure.

Table 1: Change Case Table for the system.

Enterprise

Decision

Making

Application

Migration

Policy and

Governance

Document-

Oriented

Modeling

Collaborate

(standard/

industry)

Issues

Systems

A B C D E F G H

e4 e3 e5 e1 e3 e4 e2 e3

a1 a5 a2 a4 a3 a4 a1 a5

p2 p3 p5 p3 p4 p3 p3 p4

d5 d3 d4 d3 d2 d2 d3 d4

c4 c5 c4 c5 c3 c4 c2 c3

(1:lower priority~ 5:higher priority)

Figure 2: Sustained System Interface Architecture.

Reposit

ory

Database

(future)

* A has a large number of external system interfaces that have not been shown.

Reposit

ory

Database

(future)

* A has a large number of external system interfaces that have not been shown.

A SOA-BASED SYSTEM INTERFACE CONTROL FOR E-GOVERNMENT

243

If more issues regarding E-Gov are considered, the

situation for system analysis for interface control

toward SOA is getting harder than previous case.

3 SOA-BASED ARCHITECTURE

FOR INTERFACE CONTROL

In this paper, the way to conduct system interface

control toward SOA is discussed for System

Engineer more effectively and accurately in time

manner. As there are increasing requirements for

information exchange and service sharing in a

unified manner, the situation of change request

based on health system using HL7 protocol is

considered. And the effective representation is

addressed using XML.

<?xml version="1.0" encoding="EUC-KR"?>

<Segment1>MSH

</Element1>

<Element4>LABADT</Element4>

<Element6>Security</Element6>

</Element7>

</Segment1>

<Segment2>EVN

</Segment2>

<Segment3>PID

<Field1>PATID12345</Field1>

</Element2>

<Field6>USSSA</Field6>

</Element4>

<Field1>JOHNES</Field1>

<Field2>WILLIAM</Field2>

</Element5>

<Field4>STREET</Field4>

<Field6>GREENSBORO</Field6>

</Element8>

<Field1>PATID12345001</Field1>

</Segment3>

<Segment4>NK1

<Field1>JOHNES</Field1>

<Field2>BARBARA</Field2>

</Element2>

</Element3>

</Element4>

</Segment4>

<Segment5>PV1

</Element3>

<Field2>LEBAUER</Field2>

<Field3>SIDNEY</Field3>

</Element4>

</Segment5>

</HL7import>

<?xml version="1.0" encoding="EUC-KR"?>

<Segment1>MSH

</Element1>

<Element4>LABADT</Element4>

<Element6>Security</Element6>

</Element7>

</Segment1>

<Segment2>EVN

</Segment2>

<Segment3>PID

<Field1>PATID12345</Field1>

</Element2>

<Field6>USSSA</Field6>

</Element4>

<Field1>JOHNES</Field1>

<Field2>WILLIAM</Field2>

</Element5>

<Field4>STREET</Field4>

<Field6>GREENSBORO</Field6>

</Element8>

<Field1>PATID12345001</Field1>

</Segment3>

<Segment4>NK1

<Field1>JOHNES</Field1>

<Field2>BARBARA</Field2>

</Element2>

</Element3>

</Element4>

</Segment4>

<Segment5>PV1

</Element3>

<Field2>LEBAUER</Field2>

<Field3>SIDNEY</Field3>

</Element4>

</Segment5>

</HL7import>

Figure 3: Converted XML from HL7 Sample Message.

Figure 3 is the corresponding representation of

HL7 example.

XML representation is more

understandable for System Engineer and scalable to

different format for future needs. Whenever

appropriate, it can be possibly triggered and

converted by the development.

A common

environment as shown in Figure 4 can be built for

further testing and the simulation of the impact

analysis on the interface. As an input, interface

related documentation information such as ICD, and

more for specific systems, Online log file and parsed

data at the developmental engineering lab for testing

are considered. Most components are smoothly

linked through XML and triggered by XPath.

Parsed Data

HL7 Log

Do cu me nt

Do c_ 2 _T xt

DOM Checker

Path_ Fi nder

Compare_DOMtree

Analysis_Maintainer

Ac t iv e _

Do cu me n t

Report _Generat or

IIA&T_

Mi dd l e w a r e

Case(for IA)

_Generator

Vi r tu a l

_User

_Generator

SOA-based Executable Architecture (Local Server)

Simulator (User Client)

XML_2_ Tr ee

Txt _2_ XML

Cs v _ 2 _ T xt

HL7 Test Maintainer

Tr act

html_2_Txt

Input : Document/Parsed Data/HL7 Log, Output : Active Document

Program for conversion: *_2_*, IIA & T : Interface Impact Analyzer and Tester

Figure 4: Proposed XML-based Architecture.

The simulation system is designed to equip the

scalability for the future demands. In other words,

the experiment with another non-functional

requirement system on security as well as

performance tool and an extension of the rule

domain upon the future demands are combined.

In Figure 4, in order to compare DOM tree-based

information, to maintain the HL7 message segment

table and the previous test case history data set is

needed as a database. At this point, the performing

interface issue using the local server at the

operational environment for simulation is out of

scope in this paper, as the primary purpose of the

simulation is on showing an efficiency improvement

of the suggested impact analysis for the decision-

making during developmental testing phase on

whether or not a system change can be applied to the

systems without causing any negative interface

impact.

It is ensured that there are many more problems

to which this technique can be applied. Using XML-

based information, system and testing engineers save

their time and support customers with more value-

added service by getting more realistic information

using testing requirement for impact analysis. More

information with non-functional requirement for

impact analysis in general is discussed later. Based

on the testing for the research with XML-based

ICEIS 2006 - INFORMATION SYSTEMS ANALYSIS AND SPECIFICATION

244

representation, an HL7 message transferred from

system A to system B used is found only about 30%

of the time in terms of message-level and only 50%

of the messages are being used if I consider element-

level. In other words, by using XML-based message

modeling the meaningful portion of messages is

identified for decision-making and is managed the

part required to enhance interface impact analysis as

well as updating impact analysis for each system.

4 STEP BY STEP MIGRATION

APPROACH IN E-GOV

XML is primarily used as a communication medium

between heterogeneous enterprise architectures.

Using XML notation, the time for efforts and

potential error is mitigated. This paper suggests step

by step migration approach by representing

combined scheme with HL7 testing and XML

technology. Figure 5 is an example of extracting

ICD documentation and ECP tracking for system

interface control toward SOA environment.

(a) Extracting the change of ICD.

(b) Extracting the change of ECP using DOM.

Figure 5: Executable SOA-based IC Implementation.

As shown in Figure 5, we develop step by step

approach for E-Government using converting

diverse specification through XML technology and

merge together even though engineering areas in

government are different. A two-way mapping

between generic XML workflow data and

application specific document structure is provided.

The mappings are based on XML techniques that

allow translation and manipulation of an XML

document into different representations in an

efficient way. For traversing the information under

the XML DOM tree structure, given algorithm using

XPath and XSLT is used. XPath takes a navigational

approach for specifying the nodes to be selected,

hence a large number of navigational axes have been

defined in XPath.

5 CONCLUSIONS AND FUTURE

WORK

The engineering issues in E-government toward

SOA are discussed to meet changing system

interface requirement in systems maintenance phase.

In particular, the SOA-based interface control is

focused on in the presence of interface requirement

and policy requirement for SOA in large scaled

sustained system. A baseline using XML-based

representation to handle changing system interface

requirements is considered with the process for

SOA. The XML-based step-by-step migration

approach enables supporting System Engineers’

collaboration effectively to meet the limited time

requirement. Through a health system example,

SOA-based IC framework cube are addressed as a

case.

REFERENCES

Duermeyer, K, 2005, IBM Executive SOA Summit-

Bridging Business Value to SOA

MIL-STD-498, 1997, Software Development and

Documentation, Department of Defense, December.

W3C, 2000, Extensible Markup Language (XML) 1.0 ,

W3C Recommendation, October

Yoo, N., 2004a, Impact Analysis using Performance

Requirement with Application Response Measurement

in Sustained System, In Proceedings of the

ISOneWorld Conference.

Yoo, N., 2004b, An XML-based Engineering Change

Impact Analysis with Non-Functional Requirements,

In Proceeding of SERP.

Yoo, N., 2005, XML-Based Impact Analysis Using

Change-Detection Approach For System Interface

Control , In Proceedings of International Conference

on Enterprise Information System(ICEIS).

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