Some Research Projects By Kwok-Bun Yue October 23, 2001 Bun Yue (©copyright 2000) 11/15/2018

Software Architecture Evolution (1) What does the future look like? Software architecture has changed rapidly during the last 40 years. A very coarse evolution will be shown. This is another approach to look at the importance of XML. The phases are blurred and the boundary are not clear cut. Bun Yue (©copyright 2000) 11/15/2018

Software Architecture Evolution (2) Phase 1: Mainframe. Highly centralized. Very thin clients: dumb terminals. Low connectivity Largely disconnected to outside of the organization. 60’s & 70’s: Years of the mainframe: Very few expensive computers. Low system resources -> optimization is critical. Thin clients. Low connectivity. Powerful centralized IT department. Enabling technology: Enterprise mainframe. Representative company: IBM Bun Yue (©copyright 2000) 11/15/2018

Software Architecture Evolution (3) Phase 2: Traditional 2-tiered Client and Server Fat clients: PC. Proprietary protocols. Many dedicated servers. Still largely within the organization. Inexpensive personal computers. Fat Clients Better system resources. Limited connectivity. Resources in the departmental levels. Enabling technologies: PC/client-server Representative company: Microsoft. services clients servers Organization Bun Yue (©copyright 2000) 11/15/2018

Software Architecture Evolution (4) Phase 3: Web-Based N-tiered Client-Server Internet intranet clients Web Server clients Application Server Major flow of services There are actually two major advance: Web and Middle layers. Servers: database servers, workgroup servers, etc: backend enterprise application Application servers are the middle layer, providing a layer for storing business logic. Thin clients: browsers as the Universal clients High connectivity. High system resources. Important paradigm changes: Web-centric application development. Fast changing pace. Enabling technologies: HTTP, TCP/IP, HTML, Internet standards. services servers Organization Bun Yue (©copyright 2000) 11/15/2018

Software Architecture Evolution (5) Phase 3: Web-Based N-tiered Client-Server Open protocols (because of Web). Middle layer for definition of business logic: better software development and management. Serving clients outside of the organization: Internet. The browser is becoming the universal client. Thinner clients: no need of complicated proprietary cilent software. Thinner clients (more processing done in the server side and the middle layer). Universal clients: Easy to develop a car. Now it is easy to get a car! Bun Yue (©copyright 2000) 11/15/2018

Software Architecture Evolution (6) Phase 4: Web-Centric Applications intranet Internet clients Web Server clients XML servers Application Server XML Servers External XML servers may be connected to backend servers, thus allowing communication between two organizations backend servers through XML. XML servers may be parts of the application server. Note the bi-directional flow between XML servers. The next 10+ years? Universal connectivity: anywhere, anywhen. Blurred clients and servers. PC no longer the prime connectivity tools. Human no longer the immediate consumers of data. Enabling technologies: connectivity standards (e.g. IP v6, XML, WAP/WML, Bluetooth, etc), highly portable tools (Java, Jini, XML, etc), network-enabled appliances. Potential huge social and cultural services servers Major flow of services Organization Bun Yue (©copyright 2000) 11/15/2018

Software Architecture Evolution (7) Phase 4: Web-Centric Applications Potentially thin clients. Clients and servers can be blurred: e.g. Napster. Services in and out of the organization. Data/services from many servers, inside and outside of the organization. No single organization can provide 'everything.' Much more personalized software. XML is a cornerstone technology of Web-Centric architectures, e.g. .Net of Microsoft. Client/Server blurred because of processing improvement. E.g. AOL purchase of Time/Warner. Even if an organization can provide everything, it may not be efficient. Bun Yue (©copyright 2000) 11/15/2018

Areas of Research Interests Internet Application Development Databases Concurrent Programming Distributed Systems Real-Time Programming Bun Yue (©copyright 2000) 11/15/2018

Internet Projects Explosive growth High potential for research projects Areas: infrastructures, architectures, application development Technologies: Cold Fusion, ASP, PHP, Web Application Servers, CGI-Perl, Java Servlets, JSP, XML, XSL, IMAP, LDAP, etc. Bun Yue (©copyright 2000) 11/15/2018

Internet Example: WML(1) Wireless Markup Language (WML): for delivering Internet contents to wireless device such as cellular phone. WML is based on XML. Relatively simple to develop. Bun Yue (©copyright 2000) 11/15/2018

The <card> tag stores A Simple WML Example hello.wml: <?xml version="1.0"?> <!DOCTYPE wml PUBLIC "-//WAPFORUM//DTD WML 1.1//EN" "http://www.wapforum.org/DTD/wml_1.1.xml"> <wml> <card id="Hello_World" title="Hello"> <p>This is my first card.</p> <p>Thank you.</p> </card> </wml> WML root element Like HTML, each element is usually composed of a start tag and a corresponding tag. The card element is one of the most important in WML. A card is usually displayed in a screen (scrolling allowed). The <card> tag stores information of a display screen Bun Yue (©copyright 2000) 11/15/2018

Hello.wml display The WML page is displayed simply as the right: <p>This is my first card.</p> <p>Thank you.</p> There are two paragraphs. Phone.com emulator is used. The title of the card is not displayed by phone.com emulator. The URL is artificial. Bun Yue (©copyright 2000) 11/15/2018

Another WML Example (1) A simple stock quote application. User submits one or more stock symbols and the application returns their stock quotes. Stock quote URL: http://lattes.cl.uh.edu/yue/wml/stockquotewml.pl Bun Yue (©copyright 2000) 11/15/2018

Another WML Example(2) Bun Yue (©copyright 2000) 11/15/2018

WML Research Potentials Potential research topics for WML: Design patterns. Language design issues. Navigational architectures. Security and privacy model. Smart WML generators. Bun Yue (©copyright 2000) 11/15/2018

Example: XML (1) XML stands for eXtensible Markup Language. XML is a system for defining, validating, and sharing document formats. XML is the cornerstone technology of the semantic Web, where contents have meaning beyond display information. Web-centric architectures will become increasingly important in current and future IT infrastructures. XML is a cornerstone technology of the Web-centric architecture. Bun Yue (©copyright 2000) 11/15/2018

Example: XML (2) XML application development. Generation example: Generation of XML documents. Consumption of XML documents. Generation example: http://lattes.cl.uh.edu/yue/xml/stockquote/stockquotexml.pl?stocks=ibm,msft,yue Note that, currently, you need to use Microsoft's Internet Explorer 5.0+ to view XML. Bun Yue (©copyright 2000) 11/15/2018

Example: XML (3) Consumption of XML: Viewing XML: XSL (eXtensible Stylesheet Language), XML-enabled browsers. Transforming XML documents: XSL, DOM (Document Object Model). Extracting XML document information: XML parsers. Bun Yue (©copyright 2000) 11/15/2018

Example: XML (4) Potential Research Topics in XML: XSL Design patterns. Efficient storage of XML documents. Querying XML documents. XML transformation models and techniques comparison. Web-centric application models and architectures. Many more. Bun Yue (©copyright 2000) 11/15/2018

Other Internet-Related Projects Web Caching. VoiceXML. Web software architecture. Others… Bun Yue (©copyright 2000) 11/15/2018

Database Projects Utilization of UML in data warehouse design. Executing relational algebra through the Web. Executing relational calculus through the Web. Bun Yue (©copyright 2000) 11/15/2018

Concurrent Programming Projects Implementation of various mutual exclusion algorithms in Java. Implementation of Linda-style tuple spaces in Java. Bun Yue (©copyright 2000) 11/15/2018

Distributed Systems Projects Dynamic distributed objects migration: proof of concepts done by Mr. Chris Stokes. Dynamic distributed objects migration: criteria of migration and performance evaluation. Enhancing the efficiency of CORBA/ODB adapters. Bun Yue (©copyright 2000) 11/15/2018

Real-Time Programming Projects Implementation of the Optimal Mutex Protocol in Ada and Java. Implementation of the Priority Ceiling Protocol in Java. Effects of task suspension on protocols for minimizing priority inversion. Bun Yue (©copyright 2000) 11/15/2018

Conclusions Good time to do applied computing research, especially in the area of the Internet. Don't forget to donate a scholarship to the School if your future research leads to a windfall. Thanks!! Bun Yue (©copyright 2000) 11/15/2018