An Architecture of Open and Security Internet Information
System
Yong CAO
Caoy100@yahoo.com
Computer Network Lab., Department of Computer and System Science, Nankai University, 300071
Gong-yi WU
wugy@sun.nankai.edu.cn
Graduate Institute of Nankai University, 300071
Abstract
As WWW is growing rapidly, it becomes a popular issue in computer world. Especially because of its open architecture, WWW is a best platform for establishing
computer application system of wide rang. Today, so many application systems, such as electronic business systems, have been built on WWW environments
successfully. The merging of Client/Server database management system (DBMS) and Web information system attracts people to work on it. Many products for
DBMS and WWW interconnection are available on the market, but we have to encounter new problems, such as security, certification, performance and generality.
So most of present products are not the perfect solutions. In this circumstance, after analyzed and researched these problems deeply, we raise a new four-tire Open
& Security Internet Information System (OSIIS) architecture. We defined the functions and processing procedure of every tire in OSIIS. Besides academic
research, we designed and implemented a simple Database Information Real-time Publishing System (NK_DIRPS) on Intranet. This simple system is able to
transport data between web browsers and back-end database server dynamically. Not only the browser but also the database server can send data to the other side
on its own initiative. We believe that the new OSIIS architecture will propel the WWW application and e-business development in the shortly future.
Key words:
Internet information system, Client/Server DBMS and WWW interconnection, Open Security Internet Information System
1. Overview
Since Tim Berners-Lee and his colleges constructed World Wide Web (WWW) in CERN[1], Web technology and its application provide many opportunities to us
on Internet field. And millions of Web sites have been established all over the world[2], they bring a new excellent world to us. Today, no one can suspect that
WWW is changing our thought and our future. The WWW technology propels our society into a completely span-new world.
Actually, WWW architecture comes from the merging of Internet technology and Client/Server method. WWW system includes two parts: information server
(Web server) and client system (browser). The client system can execute on most software and hardware platforms, such as PC/Windows, Workstation/Unix,
Macintosh/Mac, etc. The browser processes multimedia data and represents them to users. On the server side, a demon, named httpd, is responsible for processing
requests that come from client system.
At the same time, the Client/Server Database Management System (DBMS) becomes much mature and more perfect. Now, there is a large and powerful technical
colony to support the research and development on this field. And plentiful development tools are available on the market. Client/Server DBMS is one of major
motivates that embed the data and information into our daily life.
In computer developing history, there is an interesting rule that the new concept, new ideas or technical innovation always be started with amalgamation of new
technique and elder mature one. This rule preserves the elder achievement and good market, in the mean while it gives powerful energy and strong support to the
new developing technology. There are many successful examples about this rule, such as computer generated from computer technique (new) and communication
technique (mature) in 1960s. Today, a new innovation and development, which is the WWW-based DBMS on Internet, comes into being. It requires mergence of
WWW system, which is springing up energetically now, and Client/Server DBMS. The powerful Client/Server DBMS is able to construct a safe and reliable
environment for Internet information applications. Now, many researchers and developers have paid more attention to WWW+DBMS area. There are thousands of
solutions and products on Web and Client/Server DBMS interconnection. All these achievements make the market full of vigor and vitality.
However, we have to acknowledge that most of popular solutions on Web and DBMS interconnection are compromises. They simply mixed two systems, WWW
information system and Client/Server DBMS, into an environment. The architecture is an extension of hybrid systems and it is not a full-scale scheme. Therefore,
the performance of this type system is limited and it raises a few new problems, such as data security, operation certification and so on. The new problems will
hinder the development of Web-based information system and may freeze the enthusiasm of users. Moreover, most of present solutions and products are designed
for special purposes. They need different platforms and special system environments. So under this circumstance, it is very difficult to connect and cooperate with
different types of DBMS on WWW. This situation is away from our original goal that we want to establish an open, au pair information environment and different
type systems are able to execute harmonically and efficiently.
For above reasons, it is necessary to analyze and re-design the present architecture of Internet Information System (IIS). We need create a new architecture for IIS
and make it suit to the requests of Web system and DBMS interconnection simultaneously. The new architecture should also consider the intending technical
development. By hard working on this field, we raise a new architecture, which is Open and Security Internet Information System (OSIIS) architecture, to resolve
interconnection of Web system and Client/Server DBMS. Furthermore, the OSIIS architecture can be used to develop electronic commercial applications on
Internet, as we make it a little extension.
2. Traditional Architecture of Internet and Client/Server DBMS
Before discuss the OSIIS, let us review the architectures of traditional Internet information system and Client/Server DBMS briefly. Then we will summarize the
main characters of them.
2.1. Traditional Internet Information System Architecture
Internet was generated 30 years ago, but its actual popularity is just happened in 1990's. And the developing WWW technology is to satisfy the multimedia
demands of users. WWW adopts Client/Server architecture, which is Browser/Server mode, as shown in figure 1.
Figure 1. The architecture of WWW
Two parts compose the whole Web system: client space and server space. On the client space, browser is responsible for managing user's input/output and
communicating with Web server through Internet. Browser receives HTML-pages from Web servers and displays them onto user's computer. On the server space,
information is stored as static HTML pages on Web server. One process, httpd, is executed to monitor requests from clients and to retrieve data from native web
system or from WWW space (external web system). Finally, httpd sends results of retrieving to client system by HTML format. Server side and client side use http
protocol to communicate. On the other hand, the Web server has two ways to contact with external system. One is hyperlink, which connects different WWW sites
into a vast net; another is the pre-reserved interface such as CGI, which implements web server and non-web system connection.
Evidently, the foundation of Browser/Server architecture is static HTML pages. This means that a server response to a client request has no relations with history of
previous request and response data[3]. Then when we establish a complicated application on WWW, especially the session-oriented database application, many
inconvenient problems will be appeared. The major problems of Web-based DBMS are:
● As the format of data is stored on Web server as static HTML-pages, the updating rate of server information can not be very fast. This specialty is unsuitable
to interactive and real-time application.
● Between browser and server, the information is transported as HTML-pages, which is plan ASCII format. So it makes the system lack of security.
● The performance of data management on Web server still remains on file-driven level. It is just similar as early database management level in 1970s.
● Because pays more attention to open feature, the Web system does not provide advanced secure and reliable characters.
● The WWW architecture does not offer credit mechanism, which is very important to electronic business applications on Internet.
Therefore, in order to extend new applications on Internet, we have to find proper ways to resolve these problems.
2.2. Traditional Architecture of Client/Server DBMS
Database technology emerged in 60s, but it matured in 80s. At the end of 80s, people introduced Client/Server concepts and technique into database field. This
made DBMS market more prosperous than before. Because the major platform of traditional Client/Server DBMS is Local Area Network (LAN), so the features
and architectures of Client/Server DBMS are all designed to fit LAN environment. As shown in figure 2.
Figure 2 Architecture of traditional Client/Server DBMS
In traditional Client/Server DBMS architecture, client system initiates transaction requests. The requests are transported to server by special or universal interface,
such as CT-lib or ODBC. On the server side, server should first check user's authority and justifies the request's security level; second, it executes relevant
operations according with user's demands; finally, server delivers results to client. In this transaction cycle, the data, whatever stores and operates on server or
transports between client and server, are all binary formats. For this reason, it guarantees the performances of DBMS, such as management, maintenance and
security. On the other hand, we have an optional choice between client and server interface, specialty or generality. This feature gives us a useful measure to make
a balance for the generality and efficiency on DBMS.
However, as more WWW-based DBMS applications require WAN environment recently, the inborn shortages of traditional Client/Server DBMS become more
obviously. There are:
● Fewer flexible features. Most of Client/Server DBMS are designed for special application requirements. In general, different kinds of system have distinct
data formats and unlike realized methods. It is a very difficult problem for system administrator to exchange and to move data among different systems.
● First investment is high. The developers have not only to design or to implement server applications, but also to consider client system either. Moreover, the
administrators may be dog-tired to rush around client and server sides in order to install or to debug the systems.
● The cost of Upgrade and maintenance are also very high. Although we can upgrade and maintain client system and server system individually, the facts of
real applications are not the same. We have to consider the limits and relations between the two parts. So it causes the final work more difficulty than our
resume and more expensive than our budget.
● No unified user interface. In order to satisfy the particular requirements, different application systems have different user interfaces. The end users,
especially the non-professional users, can hardly learn or be familiar with every kind of system operations. This feature impedes the developing and updating
of DBMS.
● Unsuitable to WAN environment. Traditional Client/Server DBMS is usually developed for LAN application, therefore its architecture and design all
consider less about WAN and mobile condition. The weakness of this system feature becomes very obviously, when Client/Server DBMS emigrates onto
Internet platform directly. The problems concentrate on long delay, unreliable data transport and mobile users, etc.
2.3. The Common Architecture of Internet and Client/Server DBMS Interconnection
In order to resolve the shortages of Internet information system, which brought from traditional WWW system and Client/Server DBMS, people have to find a
compromise solution to implement world wide information communication and reserve data management. Now, the popular architecture of WWW+DBMS is a
three-tire Client/Server mode, shown as figure 3.
Figure 3 Architecture of three-tire Client/Server system
Actually, this three-tire architecture is extended from traditional Client/Server system. The whole system separates into three parts: presentation tire, function tire
and data tire.
(1)Presentation Tire (PT)
Presentation Tire is the user interface of the whole information system. It is responsible for data exchanging between user and system. The major
functions of Presentation Tire are checking the validity of user input and displaying the results that get from backend server. In WWW+DBMS
architecture, the Presentation Tire includes two parts, which are browser on fore side and Web server on backside. Browser and Web server use http
protocol to communicate. HTML is a data descriptive language that tells browser how to arrange display. In addition, JavaScript, VBScript and CGI
program can help Presentation Tire complete advanced functions on Client site.
(2)Function Tire (FT)
This tire is the core part of the application system. It includes all programs for processing transaction. In other words, except for input/output
functions, all other functions belong to this tire. In general, Function Tire is called Application server or middleware. Actually, Function Tire comes
from the client part of traditional Client/Server DBMS except for display functions. Through Web gateway, such as CGI, Function Tire connects with
Web Server. On the other side, Function Tire connects with Data Tire by special or universal interface. From this interface, Function Tire can access
the backend database. Structured Query Language (SQL) is common in use for Function Tire to access database on Data Tire.
(3)Data Tire (DT)
Data Tire is just the implementation of server part of traditional Client/Server DBMS. It is in charge of data access and database management,
especially database security and performance. The main module of Data Tire is one or more database server, such as Sybase® System 11, Oracle® 8i
and Microsoft® SQL Server 7.0, etc.
We have to accept that this three-tire architecture is a better solution to constitute a hybrid system that mixed WWW information system and Client/Server DBMS
together. Three-tire Internet information system succeed in preserving and inheriting achievement from present technology. It let us emigrate Client/Server DBMS
onto Internet more quickly and easily. But we have to point out that the three-tire architecture is only a compromise solution. It does not resolve the problems that
inherited from WWW system and Client/Server DBMS, especially in performance, certification & security and generality.
● Performance. As shown in figure 3, user's request arrives at Web server in first step. Then through Web gateway, it delivers to Application server or
middleware. Finally, it reaches database server. And the operating results will come back to the client system by the opposite direction. Therefore, a
successful data operation should pass through so many sub-systems and interfaces. Any delay on any parts of system will effect the whole system
performance. In addition, the foundation of Web protocol is stateless, so each request of data access will be looked upon as individual event. Every event
needs complete three steps to complete data transport independently. The three steps are creating connection, transferring data, destroying connection. This
stateless feature limits the system speed and makes the database access less flexibility.
● Certification & Security. Today, millions of people use Internet to assist their daily lives and thousands of companies plan to do business on Internet. This
tide of electronic business makes a great challenge not only to technical experts, but also to every user. Now, when you do business on Internet, you are in
the face of a computer, is a machine, but not an active human being. So how we change the traditional credit standard mechanism, which based on face to
face mode, into a new one, which based on human to machine mode, it is a very difficult but important problem in front of us.
From figure 3, we know that most data exchanging happens among Web server, Application server and database server. But due to
WWW system built on an open environment, so the security of this three-tire system is suspicious. Although we can setup a firewall
system between Web server and database server to protect the backend data, the firewall system may weaken the system flexibility. In
addition, the whole information system is a tight union; every part of system damaging will be a tragedy to the whole system. For an
instance, if a "hacker" tampers the homepage of a WWW system, how the whole Internet information system can be executed
continuously. Anyway, this headache situation is very harmful to user's economy and his confidence.
● Generality. The Application server or middleware of three-tire Client/Server system is a bridge between Web server and database server, so its character is
very important to the whole system performance. In actual application, this part is often implemented by special technique for performance sake. But this
performance enhancement is gained by abandoning system generality, which is one of the main purposes of WWW information system
From above discussion, we can draw a conclusion that the three-tire Client/Server architecture is just a compromise. It is not perfectly suitable to construct an
advanced Internet information system. We have to find another new solution to resolve the present problems and also to leave some leeway for the future
developing. Under this circumstance, we raise a new four-tire architecture, which is an Open Security Internet Information System (OSIIS). In this new
architecture, our major goal is to resolve security, reliability, generality and performance problems. We confirm that this four-tire system is a better solution for
WWW+DBMS.
3. Open Security Internet Information System Architecture
As we all know, system security is becoming an essential problem of Internet information system. If we can not resolve it perfectly, it will block the developing
step of commercial Internet applications without questions. From last section discussion, the main reliable feature of Internet information system comes from the
unfitness of traditional WWW architecture. Between browser and Web server as well as between Web server and DBMS, there are no special safe measures and
mechanism to guarantee system security. Furthermore, there are more and more business and service relay on Internet, it need establish a credit mechanism
between end-users and service providers so that the commercial process can be monitored and carried out under legal and just condition. Our OSIIS architecture
focuses security and certification characteristics as a major goal, so we promote the three-tire Client/Server architecture and introduce a new security & certification
tire into it.
3.1. Open Security Internet Information System Overview
As bring up a mechanism for security and certification, the whole Internet information system includes for tires, which are Presentation Tire, Function Tire,
Security & Certification Tire and Data Manipulate Tire. Shown in figure 4.
Figure 4 Architecture of Open Security Internet Information System
(1) Presentation Tire
The duties of this tire are:
● To present information on client system
● To guarantee the data security between browser and Web server
Besides common HTML files transport, we add a security channel between browser and Web server to strengthen the security performance. The data that
transported in security channel will be enciphered, and be deciphered at the destination sides of the channel. The security channel is not designed to take effect on
all data that transport between browser and Web server, but it only manages and deals with special data appointed by server. On the server side, when it is
necessary, the server will generate encryption algorithm for security channel randomly. Then downloads a copy of this algorithm to browser. This algorithm is
running as a process on server and as an applet on browser. Between this process and applet, it constructs a security channel. The important data are
enciphered/deciphered at both sides.
This mechanism of security channel offers a safe communication environment between browser and Web server. It is an extension of HTML and SSL standards.
On the other hand, owing to generate and maintain security algorithms on server randomly, the browser side need not involve in complex management procedure,
so it makes the browser separate from special servers and particular applications. People can use universal browser to cooperate with any Internet information
system. Another advantage of this mechanism is that the security algorithm will be generated on Web server dynamically, so any tracing of encryption will be very
hard. Then the Web server becomes safer than before.
In addition, the common data will still use HTML format and transport in normal way. Therefore, the performance of browser and Web server will not be effect so
much after we apply security channel.
(2) Function Tire
As the three-tire system, Function Tire is responsible for most application processes. But we redesign it more suitable to secure and universal purposes. Figure 5
shows that this tire has three types of interface.
Figure 5 Function Tire Architecture
●
●
●
User side interface (USI). It takes charge of receiving user requests and replying the results. This interface can be implement by CGI or Java techniques.
Security & Certification Interface (SCI). This interface connects Function Tire and Security & Certification Center (SCC).
Universal Data Interface (UDI). It is a universal interface to manage data access of database.
The core part of Function Tire is function scheduler. It receives requests from Presentation Tire through CGI or Java program. Then decides which function module
of Function Tire will be executed. Before access database server, it will communicate with Security & Certification Center to get encipher/decipher algorithms and
to register the data access. After receives the confirmation from SCC, the proper function module will be executed and access data from database server through
UDI.
Because maturity and compatible reasons, we design UDI by using existing database interface technique, just like JDBC, ODBC and so on. The
database-manipulating standard still adopts SQL.
(3) Security & Certification Tire
This tire is an important role among all transactions of Internet information system. The structure of Security & Certification Tire is shown in figure 6.
Figure 6 Security & Certification Tire Architecture
From figure 6, we know that SCC connects with Function Tire and Data Manipulate Tire by Security & Certification Interface (SCI). For the safe reason, this
interface can be implement by special technique, such as Java program, C++ program, etc. The main elements of SCC are request processing module (RPM),
encryption generation module (EGM) and certification module (CM).
● Request Processing Module (RPM)
When receives requests from Function Tire or Data Manipulate Tire, it checks their authorities. If they validate, RPM will start
Encryption Generation Module or/and Certification Module according with demands.
● Encryption Generation Module (EGM)
According to authority of request, EGM will launch different encryption producer and generate distinct level algorithm dynamically. Then
transports the algorithm to the requester.
● Certification Module (CM)
This module is responsible for certifying and recording the process of transaction. It will record: Transaction date and time, Host name
and host ID of attendee, Transaction description and so on. The recorded data are stored in SCC database, and then people can retrieve
them when necessary. Before CM starts certification process, it will notice Function Tire and Data Manipulate Tire, first. After both side
acknowledge it, then CM registers this transaction and records the data into its database.
Certainly, EGM and CM can execute individually. In other word, user can only ask for certification or security service separately. SCC can be implemented by the
owner of Internet information system or be provided by third-party organization that has more credit among business.
For the performance sake, not every transaction need security & certification services. The Function Tire and Data Manipulate Tire can decide the one who needs
it. This strategy gives Internet information system more flexibility and more possible extending room.
(4) Date Manipulate Tire
The Date Manipulate Tire is evolved from the server side of traditional Client/Server DBMS. From functional aspects, it inherits most advantage features of
Client/Server DBMS and gets rich development supports. There are a great number of tools and software available in this field. We just enhance the secure and
universal feature of this tire.
● Security
We add a new security & certification module (SCM) to deal with the requests of this phase. The module runs on database server as a
process. SCM communicates with DBMS by SQL API and exchanges data with SCC through SCI.
● Generality
On DBMS, we implement a universal data interface (UDI) to interact with Function Tire using SQL. The standard SQL command is
received from UDI and translates into corresponding primitive command to manipulate relevant database server. On the other hand, the
operating results will be translated into standard format and delivered to Function Tire through UDI.
3.2. A Typical Transaction Processing on OSIIS
After discuss the architecture of four-tire OSIIS, we will illustrate the procedure of a secure transaction on this kind system.
As signs in figure 4,(1)-(10)present the sequence of procedures of one total transaction.
(1) User obtains HTML pages from Web server and raises a request of data access from browser and then transfers this request to Web server by http protocol.
(2) Web server receives the request and checks user authority. If passed, it will classify the level of user's operation. When it is necessary, Web server will generate
encryption algorithm according to user's security level. Then downloads the algorithm to browser and executes it on both side.
(3) Web server will deliver user's demand to application server. The schedule program will select proper function codes and executes it on application server.
(4) The function codes complete appointed operation and judges whether to access database or not. If need access database, it notices scheduler and activates data
exchanging module.
(5) Before actual data transport, application server will apply for proper services through SCI.
(6) After received request, SCC checks the validity of it. Then executes suitable service programs.
(7) SCC informs DBMS that a requirement for database access is coming. If DBMS accepts this requirement, then goes to step (8), otherwise SCC will tell
application server that this access request is rejected.
(8) SCC delivers encryption algorithm and certification status to application server and database server, waits for both side agreements again. After they all accept
it, SCC will record this transaction into its database.
(9) Application server and database server uses UDI to exchange data. And they use the algorithm, which got from SCC, encipher important data before sending.
The application server deciphers the data that obtained from DBMS and delivers them to Web server.
(10) Web server uses the algorithm, which generated in step(2), to encipher the data again. Then sends these encrypted data to browser through security channel.
The deciphering applet of browser will translate the data and present them on user's screen.
On Internet platform, step(1)-(10)build up a secure transaction processing between browser and database server. During one transaction, browser can propose
several requests of database access. It need not establish multiple connections for each access. After the transaction ended, the Browser, Web server, Application
server and Database server will all abandon the relevant encryption algorithms, which they used in this transaction.
4. Implementation of A Simple Web Database Information Publish System
Based on our research work, we developed an interactive database information publish system on WWW. In this system, we adopt parts of the architecture that we
discussed above. We used oriented object technique and modularization skill to develop the system. And selected Java to write the core module of system.
4.1. System Elements
The whole system is divided into three modules, they are database server extension module, client extension module and real-time information publisher module.
(1) Database Server Extension Module
In the system, we designed a push-like function that can dynamically push the changed data from database server to client side. In order to implement this feature,
we add an extension module on database side. This module is responsible for capturing the data refreshing actions and sending the changed data to publish agent
module (D_Server). We use trigger and extend store procedure techniques to complete this duty.
(2) Client Extension Module (D_Watcher)
Accompany with common HTML files, D_Watcher will be downloaded to browser and execute on it. The duties of D_Watcher are:
● Receive user input
● Deliver user data to D_Server
● Use socket to communicate with D_Server
● Receive real-time data from D_Server
(3) Real-time Information Publisher Module (D_Server)
D_server is the core element. On database side, it communicates with database extension module, gains the changed data on time. On the client side, D_Server
receives the request from D_Watcher, maintains the simultaneous connections of client. After D_Server received data from DBMS, it will distribute them among
multiple connections according to user's demands.
4.2. Development and Execution Environments
When selected the developing environment, we consider more about the irrelevant feature. And for the execution platform, we pay more attention on universal and
mainstream characteristics. For performance reasons, we use a few special-programming tools, which releases with DBMS, to develop the real system.
The major configurations of developing environment are:
● Database Extension Module, developed by extended store procedure of Microsoft® SQL Server. Use Microsoft® VC++ 4.2 and BackOffice® SDK (Open
Data Service) to write the program.
● D_Server and D_Watcher, developed by Java technique. D_Server user Java application mode, and D_Watcher adopt Java applet mode.
The main execution environment is:
● Server O.S.: Windows® NT 4.0
● DBMS: Microsoft® SQL Server
● Web server: Microsoft® Internet Information Server3.0
● Web browser: Any Internet browser that supports Java is available, such as Microsoft® IE 4.0 and Netscape® Communicator 4.04.
By using this simple system, we implement a stock publishing application on WWW, shown as figure 7.
Figure 7 the Running D_Watcher
5. Conclusion
Based on traditional Client/Server DBMS and WWW architecture, we raised a complete new four-tire OSIIS architecture. In this system, we absorb advantages
from traditional structures and add a new security solution as an individual tire into it. This OSIIS architecture will provide a foundation for electronic business on
Internet in the future.
But we have to accept that our work is just beginning. There are so many problems need be solved in this field, such as:
● Specific standards and protocols for OSIIS in details
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●
●
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How to enhance the system performance
Development method and implementation tools for OSIIS
How to classify the encryption algorithm and generate them dynamically
Research on laws and rules that related with transaction certification
Anyway, the OSIIS provides a good solution for establishing a free, safe, efficient, open and regular network environment. We may find more opportunities and
more challenges from it.
Reference:
1. Berners-Lee T., Cailliau R., Luotonen A., Frystyk Nielsen H. And Secret A., “The World-wide Web”, Communications of the ACM, Vol. 37 No.8, August
1994
2. Tim Bray, "Measuring the Web", http://www5conf.inria.fr/fich_html/papers/P9/Overview.html
3. Nick N. Duan, “Distributed Database Access in a Corporate Environment Using Java”, http://www5conf.inria.fr/fich_html/papers/P23/Overview.html
4. Stephen E. Dossick and Gail E. Kaiser, “WWW Access to Legacy Client/Server Applications”, http://www5conf.inria.fr/fich_html/papers/P4/Overview.html
5. Stathes P., Drakoulis I., “A Generic Framework for the deployment of structured databases on the World Wide Web”,
http://www5conf.inria.fr/fich_html/papers/P22/Overview.html
6. Jose M. Martinez, Francisco Moran, “Catalog: a WWW Gateway for DBMSs”, NETLIB97
7. Richard., Johann., “Relational Databases and the World Wide Web: Automatic Generation of Hypertext based on Reverse-engineered Meta Information”,
NETLIB97
8. Robert., Albert., Daniel., “Comprehensive System to Develop Secure Web Accessible Databases”, http://aace.virginia.edu/aace/conf/webnet/html/352.htm
Vitae:
●
Yong CAO, got master degree of engineering from Depart. of Computer and System Sciences (CSS) of Nankai University in 1995. Major in
computer network and information system. Now, he is working at Computer Network Laboratory of CSS in Nankai University. His most interesting research
fields are: Internet/Intranet information system, WWW technology and multimedia network, electronic business, computer network management, intelligent
LAN, computer security, etc. Address: Computer Network Lab., Department of Computer and System Sciences, Nankai University, Tianjin, P.R. China,
300071. Telephone: 86-022-23508917. Email: caoy100@yahoo.com
●
Gong-yi Wu, is vice-dean of Graduate Institute of Nankai University and a professor of Dept. of Computer and System Sciences in the same
university. His most interesting research fields are: computer network and information system, computer communication, Internet/Intranet firewall, computer
network management, intelligent LAN, network education and remote training. Address: Graduate Institute of Nankai University, 300071. Telephone:
86-022-23506051. Email: wugy@sun.nankai.edu.cn.