An analysis of ERP systems based on n-tier architecture_Re
An Analysis of ERP Systems Based on N-tier Architecture
Hua-Yang Lin, Ping-Yu Hsu, Jun-Der Leu, Wen-Hsien Tsai
Department of Business Administration, National Central University
No.300, Jungda Rd, Jhongli City, Taoyuan, Taiwan 320, R.O.C.
Abstract. The proliferation of ERP systems ERP systems, and cost $10 millions for a
naturally leads to an intriguing question of moderate size company and over $100 millions
products classification. In this paper, a for a large international enterprise .
framework for analyzing ERP systems is Since ERP systems are critical to companies
proposed. This framework includes various IT and expensive to acquire, many studies have
infrastructures that can be incorporated in the n- been devoted to find the recipe for successful
tier architecture. By using cluster analysis, implementation. Among other important factors,
different groups of ERP systems are classified to product selection has been singled out by many
verify the correctness of the framework. The research reports. For example, Jason and
results may be useful for ERP vendors to Subramanian points out that in order to
improve their products strategy and help implement and use ERP system successfully,
companies to evaluate most suitable ERP companies have to select right ERP packages to
products to satisfy their requirements. match its requirement . Esteves and Pastor
also emphasize that the selection of ERP
Keywords . Enterprise Resource Planning products and consultants is an important step in
(ERP), Classification Framework, Cluster the proposed ERP Life-Cycle framework .
Analysis, N-tier Architecture Al-Mashari et al. also list correct ERP package
selection in the critical successful factors of ERP
1. Introduction projects .
Currently many ERP systems are available in
Information technology has been viewed by the market. In Taiwan along, there are 61 ERP
enterprises worldwide as vital tools in improving vendors, and the CIBRES listed approximately
efficiency and competitiveness. In the last 1500 different ERP solutions provided by a
decade, many companies turning to use variety of vendors in 2000 . These products
information systems usually known as enterprise can differ from each other very much. The
resource planning (ERP) systems to respond to differences play an important role in
competitive pressures and market opportunities software/vendor selection. The vast number of
quickly, to make product configuration flexibly vendors and the difference of functionality and
and to reduce inventory obviously . architecture have put much pressure on the
ERP systems are integrated information system selection processes. Although software
systems that support value-added processes of selection is important, to the best of our
enterprises. Based on modular software structure knowledge, no academic work has been devoted
and centralized database, information flows in to provide formal framework to compare and
manufacturing, finance, sales, distribution as contrast the characteristics of ERP systems. Such
well as human resources processes can be a framework should provide evaluation items
integrated in real time. The ERP systems have come with theoretic supports, be able to
become one of the largest IT investments for distinguish products with different functionality,
many companies during the 1990s . ERP and it should be applicable to most ERP systems.
systems are not only used by large companies but In this paper, a software architecture
also penetrated into small and medium evaluation framework for ERP systems based on
companies . client server technology, browser based
It is expensive and time consuming for computing, system integration capability and
companies to implement ERP systems . The support of globalization is proposed. To verify
companies can take many years to implement the quality of the framework, several ERP
products that are widely used in Greater China
area are evaluated with the functional list are used to be as the taxonomic characters to
designed with the framework. The results show classify ERP systems.
that the framework can be applied to a wide A simplified framework for analysis of ERP
range of software and can reasonably distinguish systems shows the IT infrastructure, major ERP
products designed with different complexities. modules, and their relationships with some
external systems by interfaces as shown in Fig. 1.
2. Methodology The major modules of ERP systems may include
finance, manufacturing, human resources, sales
The research involves four major steps to and marketing, and so on [2,7,8]. After ERP
establish and verify the ERP analysis framework. having implemented systems successfully , many
1. Identification of the simplified ERP analysis companies are considering and implementing
framework. It includes collection of various extensions to the systems. The
attributes and functions for developing the extendable external systems could include
analysis framework. The research includes supplier chain management (SCM), customer
information technology attributes, relationship management (CRM), e -business or
production functions and finance functions e-commerce solutions (B2B and B2C), data
currently. Then the simplified ERP analysis warehouse (DW), data mining (DM), business
framework of ERP systems showing the IT intelligence (BI), knowledge management (KM),
infrastructure, ERP modules and interface to and so on [13,17,18,19,25,27]. By integrating
external systems will be presented. ERP system with these external systems,
2. Identification of ERP vendors from the company can improve the relationships with
Market Intelligence Center (MIC) of suppliers and customers and provide competitive
Information Industry Institute (III) in Taiwan advantage for the organization. According to
and the Internet search. For it, the ERP Sprott  , ERP system can integrate with others
software vendors, products, and descriptions applications by integration standards (such as
will be identified and only some, but not all XML, RosettaNet) and component interface
ERP products will be surveyed in this protocols (such as CORBA, COM+ and EJB).
research. The ERP vendors must have branch For others systems to retrieve and store data in
offices in Taiwan and the Mainland China at the ERP system, there are three most used
the same time. These vendors include methods from the experiences of professional
international and local ERP vendors. consultants, of ERP vendors and consulting
3. The function list is sent to the selected ERP companies. The three integration methods
vendors. The data filled by vendors are include predefined programs, temporary data
verified with independent experts or users in files and read/write tables in database directly. In
customer sites. Only the reports that have this paper, the focus will be on IT infrastructure
consistent view from both parties are that supported the ERP system operation.
reserved for clustering analysis.
4. Identification and analysis of the IT External Systems
attributes contained in the ERP products. KM BI DW DM
Each key IT attribute has a variety of sub- SCM CRM B2B B2C
features or capabilities. These attributes of
different ERP products were identified and Intergration
analyzed. By evaluating the relationship Standards interface
among the aggregations of ERP attributes
using cluster analysis, the different groups of ERP Modules
ERP products might be identified and Manufacturing Finance Human Resources . . .
described. IT Attributes
Client Web AP DB System enabling
Server Server Server Architecture
3. A framework for analyzing ERP
systems Figure 1. Framework for analyzing ERP
Because ERP systems are continuously
evolving in terms of technology and functionality IT attribute is the technology infrastructure to
, in this paper both functions and attributes support the execution of ERP systems. The ERP
systems transform the value chain methodology
into reality by applying software systems to links management issue rather than IT responsibility
activitie s (functional areas) in a client/server and data management feature is categorized to
architectural environment [1,11,20,24]. In the database server attribute. Hence, this paper does
viewpoint of IT infrastructure, ERP systems have not include these two business-enabling features.
three components: client/server system, From above research the IT attributes will be
enterprise-wide database as well as the studied under the framework given by the Fig. 2.
application modules . User interface is one
characteristic of the client/server model , ITAttributes
which is typically a graphic user interface (GUI). 1.Client 4.DatabaseServer
According to Sinha , there are following a.OperatingSystem(OS) a. Database support
key issues that must be considered for a
Ÿ Client: (1)workstation operating system, cG I
. U c.Scalability
(2)hardware constrains, (3)connectivity d.Divisionofresponsibility
constraints, (4)objected-oriented design,
(5)GUI, (6)division of responsibility. a. 2-tiers
Ÿ Server: (1)scalability, (2)server interface, a.Webserversupport b. 3-tiers
(3)gateway to mainframe, (4)disk space, b.Connection c.4-tiers
(5)security and access control, (6)backup,
recovery and logging, (7)fault tolerance and 6.Business-enablingFeatures
uninterrupted power supply, (8)performance a. Scability
and system management, (9)internetworking. b.Serverinterface Integrationstandards
Because information technologies have made c.Gatewaytoothersystems Componentinterfaceprotocols
progress on hardware and software continuously,
some key issues have been excluded from this d.Modifications
paper, e.g., hardware constraints, disk space and e. Backup, recovery
internetworking. Some issues that are not related f.Logging
to ERP systems have been neglected also, e.g., g.PerformanceandMgt.
OO design, fault tolerance and UPS. The
gateway to mainframe issue has been revised to Figure 2. Framework of IT attributes
gateway to externa l systems based on above
framework. 4. Data collection and verification
Information technologies have evolved from
client/server computing to the Internet era. The A total of 61 ERP software vendors were
system architecture extends to 4-tiers web-based identified from the Market Intelligence Center
architecture . The web-based architecture (MIC) of Institute of Information Industry (III) in
consists of four layers: client, web server, Taiwan. This vendors list consists of major ERP
application server and database server. Owing to vendors in Taiwan and well-known international
the development of mobile technology, the ERP vendors which have branch offices or
mobile devices can be used to access information agents in Taiwan. Among the 61 companies, 32
systems . Users may connect to ERP systems are taken away from the list since they do not
by browsers and mobile devices so that the ERP have branches to operate in Mainland China or
systems can be integrated to the supply chain Hong Kong. Phone calls were made to the left 29
management (SCM) system, customer companies to invite them to join the research. 25
relationship management (CRM) system, and so out of the 29 companies agreed to review the
on. forms derived from analysis framework.
In addition to information infrastructure based After reviewing the framework, 16 companies
on n-tiers architecture, Davenport  pointed out do not express their interest to attend the research.
that ERP systems should include some specific After one month of intensive communication, 9
technical or business-enabling features. These out of the 25 companies return their forms. Such
business-enabling features consist of data a low return rate we believe is caused by two
ownership, procedures, transaction visibility, problems. One is that the framework may reveal
global or multilocal, data management, that their IT attributes have a lot of room to grow.
modifications and best practices orientation. The The second one is because the framework
data ownership feature is more likely a requires experts to fill out the form and they are
extremely busy during the intensive
communication period. However no company Table 2. Features associated with the IT
has complained that their products cannot be attributes
analyzed by the framework. IT Attributes A B C D E F
To assure that the data filled are accurate, Client (14) 7 12 12 6 13 5
Web server (6) 0 1 5 0 6 0
telephone interviews are also performed to make Application server (21) 14 9 21 16 20 6
sure the experts filling the data fully understand Database server (10) 4 1 5 8 6 2
the questionnaire. To verify the data, the same System architecture (3) 1 3 1 2 3 1
form is also used to interviewed customers of the Business-enabling features (10) 7 6 7 6 8 7
Total (64) 33 32 51 38 56 21
companies or experts who do not work for the
vendors. Three out of the nine returned
questionnaires cannot be confirmed by such a Combined the total IT attributes, the product
verification procedure either due to customers E supports most of the features for IT attributes.
did not use the latest versions or the experts are For local ERP products, the product D supports
out of the country when the survey was most of the features for IT attributes. There is no
performed. Hence, the framework verification huge difference between the two international
phase successfully obtains the analysis reports of ERP products about IT attributes. But for the
six products from six companies. Their four local ERP products, they have bigger
characteristics are listed in Table 1. differences among them. The comparisons of six
ERP products for all the six IT attributes are
Table 1. Characteristics of the ERP shown in Fig. 3.
products under analysis
Sym Year of Major Company profile
bol founded market area
Number of IT features
A 1982 Taiwan and The largest ERP vendor in 20
China Taiwan 15
B 1994 Taiwan and Aggressively expending ERP
China vendor 10
C 1977 Worldwide The largest ERP vendor in 5
D 1987 Taiwan and The second ERP vendor in 0 Client Web server P server DB server
A System architecture
China Taiwan IT attributes
E 1972 Worldwide The largest ERP vendor A B C D E F
F 1994 Taiwan and Aggressively expending ERP Figure 3. Comparisons of six ERP products
based on six IT attributes
5. Analysis of ERP systems
5.2 Cluster analysis
The IT attributes include client, web server,
The different ERP systems can be placed to
application server, database server, system
dissimilar clusters by using the cluster analysis.
architecture and business-enabling functions.
The goal of cluster analysis is to classify the ERP
These attributes support the infrastructure
systems into clusters. In such a way, the ERP
requirements for ERP systems from the aspect of
systems with similar number of attributes or
functions are placed in the same cluster. The
result of the survey is clustered with complete
5.1 The result of the analysis link cluster methodology to examine if products
The features associated with the IT attributes under survey can be naturally grouped. The
for all the six ERP products are shown in Table 2. result of the cluster is to verify if the analysis
The values of each column mean the number of framework can reasonably distinguish products.
features for each ERP products supported. The In this research, the agglomerative
number contained within parentheses is the total
hierarchical clustering is used to analyze the IT
number of features surveyed for each IT attribute. attributes of ERP systems. All the surveyed
There are in total sixty-four features that results are analyzed by SPSS 10.0 software and
categorized as six IT attributes including client, used complete-linkage algorithm. The Fig. 4
web server, application server, database server, shows the results of cluster analysis for six ERP
system architecture and business-enabling systems based on IT attributes.
systems and the support of business enabling
The framework has solid theoretic foundation
since it based on client/server architecture 
and web base computing  to develop system
attributes and global business requirement to
derive business enabling feature . The
Figure 4. Cluster analysis of ERP systems clustering analysis in the verification phase
based on IT attributes implies the framework can reasonably
distinguish products. During the process of
From Fig. 4, we can naturally cut the ERP collecting ERP product analysis reports, we have
systems into two groups by setting the distance at not found any company complaining that the
15. The two different groups are: framework is not suitable to evaluate their
Ÿ Group I: international vendors, the top leaders products. From the friendly response, we have
in ERP worldwide market. strong confidence that the framework can be
Ÿ Group II: local vendors, the top ERP vendors applied to major ERP systems.
and highest market share on small and medium The study tries to establish the IT attributes
enterprises in Taiwan. analysis framework of ERP systems. However,
Among the local ERP vendors, the four as the discussion in section 1 shows, ERP has
companies can be divided into two subgroups by many strong functional aspects in handling
setting the distance at 10. The major reason is business processes. In the future work, we
that only one ERP system supports web suggest at least manufacturing and financial
architecture while the others not. analysis should be added to the analysis
The result matches products’ general image framework since financial modules have the
and thus implies that the analysis framework can highest installed priority  and ERP systems
reasonably distinguish products. have the highest penetration rate in
manufacturing industries .
6. Conclusions and future works
Product selection has been singled out by
many research reports. After checking some The research is partially supported by the
local and international renowned ERP software MOE Program for Promoting Academic
products, the similarities and dissimilarities of Excellence of Universities of R.O.C. under the
ERP systems can be found. The classification Grant Number 91-H-FA07-1-4.
framework developed in this paper can help the
software vendors to improve their ERP products 8. References
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