Wei's Blog

The Continuation of this Blog

2008-02-20T00:27:00.004+08:00

This blog was previously used as coursework of a course about Internet Application Development that I learnt [1]. During that period of time, I regularly wrote and posted technical articles about the development and evolvement of Internet related technologies on this blog. I saw that the posts got found through Internet search engines. I was happy to see that people were glad to read them. I myself also learnt a lot from writing them.

The mentioned course was over a long time ago. Now I am just starting to make use of this blog again. I would like to write articles about Internet related technologies, as well as my findings on software development and computer applications. Welcome and any comment will be appreciated. Thank you.

[1] http://chenwaynet.blogspot.com/2007/01/internet-application-development-course.html

Applications of Web 2.0

2007-04-15T17:32:00.000+08:00

Web 2.0 refers to the second-generation of Web-based services that emphasize online collaboration and sharing among users [1].It has recently attracted more and more people's attentions because of the popularity of the Websites with user generated content such as Flickr, Myspace and Youtube.
Youtube [2] is a famous Website in which users can share videos with others. It is a typical Web 2.0 application. The more the users share videos, the more videos they can watch. In this application, it is the video data that users upload, not the software itself, that is worth a lot of money. People are willing to share videos, because they share for the community and for themselves.

[1] http://en.wikipedia.org/wiki/Web20
[2] http://www.youtube.com/

Advantages and Disadvantages of ASP.NET

2007-04-08T02:08:00.000+08:00

ASP.NET has been widely used as a Web application development framework recently. The main advantage of ASP.NET is that it is easy to use and usually less lines of code are needed if written in ASP.NET compared with Java EE. Another advantage is that the .NET platform supports a lot of kinds of programming languages so that every programmer can get started with it quickly.
There are also some disadvantages for ASP.NET. One main disadvantage is that ASP.NET applications can only run on Windows platform [1]. Both Windows Server 2003 and VS.NET environment cost a lot money to buy. This limits its use.

[1] http://weblogs.java.net/blog/pbrittan/archive/2003/08/java_vs_net_par.html

Advantages and Disadvantages of Java EE

2007-04-01T22:49:00.000+08:00

Java EE is formerly known as J2EE before its version 1.5 [1]. It stands for Java Platform, Enterprise Edition. It is a programming platform that is used to develop enterprise applications. Java EE includes a set of services that can facilitate quick development of stable and powerful enterprise level applications. It has been widely used in many important applications, especially commercial ones.
There are advantages and disadvantages for Java EE platform. One advantage is that it supports quick distributed enterprise application development. People can build complex applications quickly based on the platform using its services and APIs.
Java EE also has some disadvantages. One of them is that only Java programming language gets supported on the platform [2]. This may limit the use of the platform.

[1] http://en.wikipedia.org/wiki/J2ee
[2] http://www2.sys-con.com/ITSG/virtualcd/java/archives/0802/jdjinterview/index.html

What are the Merits of LAMP?

2007-03-24T22:54:00.000+08:00

LAMP, which stands for "Linux + Apache + MySQL + PHP", is a set of software that can be used to build a Web server. It has long been used as a popular software bundle by many hosts on the Internet. The acronym LAMP was invented by Michael Kunze in an article for a Germany computing magazine in 1998 [1].
There are merits of the LAMP software bundle. The LAMP solution is free [2]. Adopting LAMP Web server can save a lot of money compared with the "Windows + IIS + ASP(.NET) + MS SQL Server" solution. The LAMP software is open source. In this way bugs/holes can be found and fixed quickly [3]. People do not know the holes in Microsoft software, but sophisticated hackers do. This leads to a vulnerable system on the server, which is not desired. Furthermore, the LAMP solution is stable. One can have a heavy load Linux server continuously run for years without rebooting. This provides a 7*24 solution to serious Web applications.

[1] http://en.wikipedia.org/wiki/LAMP_%28software_bundle%29
[2] http://www.linuxjournal.com/article/7837
[3] http://www.webmasterworld.com/forum40/962.htm

Ajax Development Frameworks

2007-03-18T17:17:00.000+08:00

Ajax is a novel technique that has been widely used by some newly launched Web applications as well as some big online companies recently [1]. Ajax development frameworks have been developed to facilitate efficient development of Ajax applications.
There are various kinds of Ajax development frameworks today. The same program function can be written differently using different Ajax frameworks [2]. Generally speaking, existing Ajax development frameworks depend highly on the underlaying development environment and programming language that is used in the application. One example is that Google Web Toolkit is based on Java and can convert Java classes into browser-compliant JavaScript and HTML [3]. Cross environment frameworks are also developed in these days. This is especially true for some lightweight Ajax frameworks. For example, Sajax framework supports various server-side languages and development environments [4]. Choosing a good framework is the basis and also the first step of building an Ajax-based Web application and therefore is usually considered very important.

[1] http://www.developer.com/java/other/article.php/3567706
[2] http://www.codeproject.com/Ajax/IntroAjaxASPNET.asp
[3] http://code.google.com/webtoolkit/
[4] http://www.developerzone.biz/content/view/197/50/

Advantages and Disadvantages of Ajax

2007-03-09T23:42:00.000+08:00

Ajax is a novel method for Web-based application development. It stands for Asynchronous JavaScript and XML. The word is firstly used by Jesse James Garrett in February 2005 [1, 2]. The technique has been widely used by many applications on the Web.
There are advantages and disadvantages for Ajax techniques. One important advantage is that Ajax makes Web pages fancy. It facilitates complex interactions between the application and the users without the need of reloading the entire page [3].
Ajax techniques also have some disadvantages. One disadvantage is that it increases the development time and cost of Web applications. It is reported that Ajax-based applications are hard to build and maintain [4]. Another disadvantage is that Ajax decreases the accessibility of Web applications. Not all browsers support JavaScript and XMLHttpRequest, especially some old browsers, mobile devices and screen readers [5].
As the development of the Ajax techniques, it could be useful to learn it well.

[1] http://en.wikipedia.org/wiki/Ajax_%28programming%29
[2] http://www.adaptivepath.com/publications/essays/archives/000385.php
[3] http://dev2dev.bea.com/pub/a/2005/08/ajax_introduction.html
[4] http://www.interaktonline.com/Support/Articles/Details/AJAX:+Asynchronously...309
[5] http://www.webaim.org/techniques/ajax/

Advantages and Disadvantages of JavaScript

2007-03-04T15:29:00.000+08:00

JavaScript is the most popular scripting language that is used in the client-side script programming on the Web. A lot of kinds of modern Web browsers have support of it. And many Websites nowadays contain features that are based on JavaScript. JavaScript can make dynamic updates to a HTML document in a browser and therefore can facilitate complex interactions between users and browsers or even servers.
JavaScript has some advantages and disadvantages. One advantage is that it runs fast since it is a client-side language. The code can be run immediately in the browser instead of having to contact the server and wait for an answer [1].
There are also disadvantages. One important disadvantage is that not all browsers can recognize JavaScript [2]. Using JavaScript limits the accessibility of a Website since old browsers, some mobile devices or screen readers do not recognize JavaScript. Besides, some users turn off the JavaScript support in their browsers for security reasons. It is reported that about 3% to 10% Web users turn off JavaScript support [3]. Another problem is that different browsers read JavaScript programs differently. It is suggested that the only way of being absolutely sure that a page will work on different browsers is to test it as widely as possible [4].

[1] http://www.mediacollege.com/internet/javascript/pros-cons.html
[2] http://zonorus.marlboro.edu/~lcarilli/designll/dis.htm
[3] http://www.killersites.com/mvnforum/mvnforum/viewthread?thread=2058
[4] http://www.wdvl.com/Authoring/JavaScript/PracticalJS/practicaljs1_3.html

Software Architectures

2007-02-15T16:28:00.000+08:00

Software architecture is the high level component design of the software. Eoin Woods defines that software architecture is the set of design decisions which, if made incorrectly, may cause your project to be canceled [1]. This definition shows clearly the importance of the software architecture in a software development project. Since architecture design is in the early stage of a software development process before the detailed design, a good design with less mistakes could save a lot of money and manpower in the software development.
One of the important tasks of the software architecture design is to decompose the whole system into components or subsystems. The software architecture discipline is centered on the idea of reducing complexity through abstraction and separation of concerns [2]. A good decomposition satisfies the principle of loose coupling between components (or pieces), facilitated by clean interfaces, simplifying the problem by dividing it into reasonably independent pieces that can be tackled separately [3].
There are a lot of kinds of software architectures that can be used when designing a software system, such as client-server, peer-to-peer, three-tier model, structured, service-oriented architecture, etc [2]. Software architects should make used of them when designing software architectures.

[1] http://www.sei.cmu.edu/architecture/definitions.html
[2] http://en.wikipedia.org/wiki/Software_architecture
[3] http://www.bredemeyer.com/whatis.htm

The Python Programming Language

2007-02-10T16:06:00.000+08:00

I have learned the Python programming language in the lectures in the last week and this week in the Internet Application Development course. According to the Python tutorial, Python is an easy to learn, powerful programming language [1]. It can be used to implement CGI programs easily just like other scripting languages such as PHP and Perl.
Unlike some well known scripting languages, the grammar of the Python language is very different from the traditional C programming language. This makes it a little bit difficult to learn. One example is that Python uses indentation to represent block structure rather than using brackets or "begin...end" blocks. This may cause confusion when the indentation is a mix of spaces and tabs on some platforms.
Python implements some functions of Object-oriented programming. This makes it easy to write complex applications. Furthermore, Python provides a set of modules that extends its functionality.

[1] http://docs.python.org/tut/node1.html

Advantages and Disadvantages of CGI

2007-02-04T22:47:00.000+08:00

CGI is a standard protocol for interfacing external application software with a Web server [1]. It has been widely used for implementing dynamic generated pages on the Web.
There are advantages and disadvantages to CGI programs. One advantage of CGI programs is that they are language independent [2]. CGI programs can be written in any language that allows one to write normal programs since they are executed in the same way as the normal programs. Another advantage of CGI is that it's a very simple interface [3]. It's not necessary to have any special library to create a CGI program, or write programs using a particular API. Instead, CGI programs rely on the standard concepts of standard input, standard output, and environment variables to communicate with the Web server.
There are also disadvantages to CGI programs. One disadvantage is that CGI programs are slow since they need to fork a new process for every HTTP request and the database connection must be reopened for the next instance of the program, which is quite costly [4]. One solution is to use FastCGI instead of CGI. FastCGI implements a technique using which forking one process for every request is not necessary, therefore can improve the performance.

[1] http://en.wikipedia.org/wiki/Common_Gateway_Interface
[2] http://www.scit.wlv.ac.uk/~jphb/sst/basics/cgiintro.html
[3] http://proquest.safaribooksonline.com/0672324040/ch01lev1sec5
[4] http://proquest.safaribooksonline.com/1565923790/ch15-27259

Integrated Query on the Web

2007-01-26T20:27:00.000+08:00

Recently, I read an interesting paper about an integrated query interface for Websites [1]. There can be a big amount of Websites where we can retrieve information about a certain domain. Many of those data can be retrieved through queries to complex Web forms. It could be costly for a user to query individual Websites respectively. Therefore, an integrated query interface is needed. A user can enter his/her query at the central interface. The interface then dispatches the query to individual data sources, retrieves the results, and displays them to the user after some sorting or fusion.
I think the work proposed is very interesting because it provides a central interface for online users to query information in a domain. It is a novel idea for Internet application development.

[1] Eduard C. Dragut, Clement T. Yu, Weiyi Meng. Meaningful Labeling of Integrated Query Interfaces. VLDB 2006: 679-690.

My Personal Website

2007-01-26T20:14:00.000+08:00

It can be a pleasure to own a Website on the World Wide Web where one can introduce himself/herself, write diaries and whatever he/she likes. In the Internet application development course, each student is required to build a personal Website. The Website should be written by hand and validated by the W3C validators [1, 2]. Furthermore, tables are not allowed to be used for the page layout.
My homepage is located at http://www.cs.cityu.edu.hk/~wchen2/cs5281/. Everyone in the world is welcome to visit my site. I hope you enjoy it.

[1] http://validator.w3.org/
[2] http://jigsaw.w3.org/css-validator/

The History of the Web

2007-01-21T19:02:00.000+08:00

The World Wide Web is now popular and is widely used all over the world. However, the history of the Web is not long. Tim Berners-Lee invented WWW in March 1989 at CERN [1]. It was first developed as a common presentation method for physicists from around the world to share data [2]. He introduced the HTTP protocol and also the HTML file format for hyper-text transferring and presentation [3, 4]. The first Website on the Web was http://info.cern.ch/. At first there were only several Websites, but now there are a lot of them. Nowadays people around the world surf on the Internet to visit those Websites every day.
Why did the Web develop so quickly? I think it is mainly because of people’s high information demand. The Web provides a method using which people can share information on a global scale. As the invention and development of Web 2.0, I think the information sharing could be more convenient and the Web will be hotter than ever before.

[1] http://www.zeltser.com/web-history/
[2] http://en.wikipedia.org/wiki/History_of_the_World_Wide_Web
[3] http://en.wikipedia.org/wiki/HTTP
[4] http://en.wikipedia.org/wiki/HTML

The Internet Application Development Course

2007-01-18T18:42:00.000+08:00

This blog will be used in this semester for a course that I am learning. The name of the course is Internet application development. The course covers technologies for developing Internet applications, including XHTML, CSS, CGI, Python, etc. Some Web-based architectures/platforms are also covered. More information about the course can be found at the course Website, which requires a student account to access.
I plan in this semester to read some books and articles about the Internet application development and try to do more exercises. I will post my learning experience on my blog. I hope I can learn the course well in the semester.

My First Post

2007-01-15T16:05:00.000+08:00

Now I have my blog space on blogger.com. I will write articles on my blog about my studies and my life. I hope you enjoy it and have fun with it.