Techno Page - By Harendra Alwis

Brain tissue for microprocessors ?
The latest news from the world of artificial intelligence suggests the use of living tissue in microprocessors! Intelligent beings learn from experiences and have the ability to convert data into information and then generalize that information to gather more knowledge. The problem is that it is very difficult to make silicon chips that can mimic this type of behaviour, because they are nothing but a set of transistors printed on a silicon wafer.

On the other hand, brain cells have the ability to re-organize themselves, in effect changing the circuitry of the whole brain. This is believed to be the reason behind our ability to learn from past experience.

So believe it or not, there are scientists, who are actually trying to make microprocessors out of living brain tissue at this very moment! What do you think will happen if they manage to make it work? Write in to technopage and let us know while I keep you posted on their progress.

Design and structure with UML
By Kushan Amarasiri
Business applications must be structured in a way that enables scalability, security and robust execution under stressful conditions and their structure must be defined clearly to facilitate easy maintenance. Well-designed architecture benefits any programme.

One of the methods used to design and structure application development is known as UML, which is based on object orientation methods. UML helps you specify, visualize, and document models of software systems including their structure and design. Using any one of the large number of UML-based tools in the market, you can analyze your application requirements and design a solution that meets them, representing the results using twelve standard diagram types.

With UML, you can model just about any type of application, running on any combination of hardware, operating system, programming language, and network. Its flexibility lets you model distributed applications that use just about any middleware on the market. UML is used with object-oriented languages and environments such as C++, Java, and C#. You can use it to model non-OO applications as well, such as Fortran, VB or COBOL. Some of the UML tools analyze existing source code and reverse-engineer it into a set of UML diagrams. Other tools generate program language code from UML, producing almost bug-free, deployable applications that run faster if the code generator incorporates best-practice scalable patterns for, e.g., transactional database operations or other common program tasks.

UML defines twelve types of diagrams, divided into three categories: Four diagram types represent static application structure; five represent different aspects of dynamic behaviour; and three represent ways you can organize and manage your application modules.

Structural Diagrams include the Class Diagram, Object Diagram, Component Diagram, and Deployment Diagram.

Behavior Diagrams include the Use Case Diagram (used by some methodologies during requirements gathering); Sequence Diagram, Activity Diagram, Collaboration Diagram, and State Chart Diagram.

Model management diagrams include packages, subsystems, and models.

Two features add to the expressiveness of UML. Object Constraint Language (OCL) has been part of UML since its beginning, while the Action Semantics extension is a recent addition.

Object Constraint Language lets you express conditions on an invocation in a formally defined way. You can specify invariants, pre-conditions, post-conditions, whether an object reference is allowed to be null and some other restrictions using OCL.

Action Semantics UML Extensions let you express actions as UML objects. An Action object may take a set of inputs and transform it into a set of outputs, or may change the state of the system, or both. Actions may be chained, with one Action's outputs being another Action's inputs. Actions are assumed to occur independently.

The latest release of UML is version 2.0, which was released in mid-2001. UML is the de-facto standard in the software industry for the development of object oriented application systems.

Explore cyberspace through the window of your Inbox
By Sennan Constantine
Last week we pointed out that you can actually browse the Internet through email. I will not hold you in suspense any longer as we shall continue the exploration of cyberspace through the window of your Inbox.

If you find an interesting FTP site in the list, send an e-mail to one of these ftpmail servers:

ftpmail@academ.com (United States)
ftpmail@btoy1.rochester.ny.us (United States)
ftpmail@cnd.caravan.ru (Russia) - SLOW
ftpmail@dna.affrc.go.jp (Japan)
ftpmail@ftp.sunet.se (Sweden)
ftpmail@ftp.uni-stuttgart.de (Germany)
ftpmail@gu.net (Ukraine)
ftpmail@ml.imasy.or.jp (Japan)
ftpmail@mail.iif.hu (Hungary)
ftpmail@mercure.umh.ac.be (Belgium)
ftpmail@uar.net (Ukraine)
Note: There are other restricted-use FTPMAIL servers listed at
http://www.expita.com/servers.html
See the "WWW by E-mail" section for help retrieving this file.
It doesn't really matter which one you choose, but a server that is geographically close may respond quicker. (Please DON'T use the first one in the list just because it's there!) In the body of the note, include these lines:

open <site>
dir
quit

This will return to you a list of the files stored in the root directory at that site. See the figure below for an example of the output when using "ftp.simtel.net" for the site name.

In your next email message you can navigate to other directories by inserting (for example)

cd pub (use "chdir" if "cd" doesn't work)
before the "dir" command. (The "cd" means "change directory" and "pub" is a common (public) directory name, usually a good place to start.) Once you determine the name of the file you want to retrieve, use: get <name of file> in the following note instead of the "dir" command. If the file you want to retrieve is plain text, this will suffice. If it's a binary file (an executable program, compressed file, etc.) you'll need to insert the command: binary, in your note before the "get" command.

Tip: Many directories at FTP sites contain a file called 00-index.txt, README, or something similarly named which gives a description of the files found there. If you're just exploring and your "dir" reveals one of these filenames, do a "get" on the file and save yourself some time. (To be continued)

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