ALL ENGINEERS MUST SEE THIS

             Most of the engineering collage in tamil nadu send their students out of the collage or they torcher  them to study by keeping special class till 8am to 6pm.If this continue in  our contry then most of the people will be affected mentally and they will be depressed.The eng students are not treated properly and the collage tells them to be just a book warm.Then how will our country get technically skilled professional.So our govt must concern this as a serious issue and take steps .Other ways our country future is in threat

20 GOOGLE SECRETS

Google is clearly the best general-purpose search engine on the Web.But most people don't use it to its best advantage. Do you just plug in a keyword or two and hope for the best? That may be the quickest way to search, but with more than 3 billion pages in Google's index, it's still a struggle to pare results to a manageable number.

But Google is an remarkably powerful tool that can ease and enhance your Internet exploration. Google's search options go beyond simple keywords, the Web, and even its own programmers. Let's look at some of Google's lesser-known options.

Syntax Search Tricks

Using a special syntax is a way to tell Google that you want to restrict your searches to certain elements or characteristics of Web pages. Google has a fairly complete list of its syntax elements at

www.google.com/help/operators.html

. Here are some advanced operators that can help narrow down your search results.

Intitle: at the beginning of a query word or phrase (intitle:"Three Blind Mice") restricts your search results to just the titles of Web pages.

Intext: does the opposite of intitle:, searching only the body text, ignoring titles, links, and so forth. Intext: is perfect when what you're searching for might commonly appear in URLs. If you're looking for the term HTML, for example, and you don't want to get results such as

www.mysite.com/index.html

, you can enter intext:html.

Link: lets you see which pages are linking to your Web page or to another page you're interested in. For example, try typing in

link:http://www.pcmag.com

Try using site: (which restricts results to top-level domains) with intitle: to find certain types of pages. For example, get scholarly pages about Mark Twain by searching for intitle:"Mark Twain"site:edu. Experiment with mixing various elements; you'll develop several strategies for finding the stuff you want more effectively. The site: command is very helpful as an alternative to the mediocre search engines built into many sites.

Swiss Army Google

Google has a number of services that can help you accomplish tasks you may never have thought to use Google for. For example, the new calculator feature

(www.google.com/help/features.html#calculator)

lets you do both math and a variety of conversions from the search box. For extra fun, try the query "Answer to life the universe and everything."

Let Google help you figure out whether you've got the right spelling—and the right word—for your search. Enter a misspelled word or phrase into the query box (try "thre blund mise") and Google may suggest a proper spelling. This doesn't always succeed; it works best when the word you're searching for can be found in a dictionary. Once you search for a properly spelled word, look at the results page, which repeats your query. (If you're searching for "three blind mice," underneath the search window will appear a statement such as Searched the web for "three blind mice.") You'll discover that you can click on each word in your search phrase and get a definition from a dictionary.

Suppose you want to contact someone and don't have his phone number handy. Google can help you with that, too. Just enter a name, city, and state. (The city is optional, but you must enter a state.) If a phone number matches the listing, you'll see it at the top of the search results along with a map link to the address. If you'd rather restrict your results, use rphonebook: for residential listings or bphonebook: for business listings. If you'd rather use a search form for business phone listings, try Yellow Search

(www.buzztoolbox.com/google/yellowsearch.shtml).

Extended Googling

Google offers several services that give you a head start in focusing your search. Google Groups

(http://groups.google.com)

indexes literally millions of messages from decades of discussion on Usenet. Google even helps you with your shopping via two tools: Froogle

CODE

(http://froogle.google.com),

which indexes products from online stores, and Google Catalogs

CODE

(http://catalogs.google.com),

which features products from more 6,000 paper catalogs in a searchable index. And this only scratches the surface. You can get a complete list of Google's tools and services at

www.google.com/options/index.html

You're probably used to using Google in your browser. But have you ever thought of using Google outside your browser?

Google Alert

(www.googlealert.com)

monitors your search terms and e-mails you information about new additions to Google's Web index. (Google Alert is not affiliated with Google; it uses Google's Web services API to perform its searches.) If you're more interested in news stories than general Web content, check out the beta version of Google News Alerts

(www.google.com/newsalerts).

This service (which is affiliated with Google) will monitor up to 50 news queries per e-mail address and send you information about news stories that match your query. (Hint: Use the intitle: and source: syntax elements with Google News to limit the number of alerts you get.)

Google on the telephone? Yup. This service is brought to you by the folks at Google Labs

(http://labs.google.com),

a place for experimental Google ideas and features (which may come and go, so what's there at this writing might not be there when you decide to check it out). With Google Voice Search

(http://labs1.google.com/gvs.html),

you dial the Voice Search phone number, speak your keywords, and then click on the indicated link. Every time you say a new search term, the results page will refresh with your new query (you must have JavaScript enabled for this to work). Remember, this service is still in an experimental phase, so don't expect 100 percent success.

In 2002, Google released the Google API (application programming interface), a way for programmers to access Google's search engine results without violating the Google Terms of Service. A lot of people have created useful (and occasionally not-so-useful but interesting) applications not available from Google itself, such as Google Alert. For many applications, you'll need an API key, which is available free from

CODE

www.google.com/apis

. See the figures for two more examples, and visit

www.pcmag.com/solutions

for more.

Thanks to its many different search properties, Google goes far beyond a regular search engine. Give the tricks in this article a try. You'll be amazed at how many different ways Google can improve your Internet searching.

Online Extra: More Google Tips

Here are a few more clever ways to tweak your Google searches.

Search Within a Timeframe

Daterange: (start date–end date). You can restrict your searches to pages that were indexed within a certain time period. Daterange: searches by when Google indexed a page, not when the page itself was created. This operator can help you ensure that results will have fresh content (by using recent dates), or you can use it to avoid a topic's current-news blizzard and concentrate only on older results. Daterange: is actually more useful if you go elsewhere to take advantage of it, because daterange: requires Julian dates, not standard Gregorian dates. You can find converters on the Web (such as

CODE

http://aa.usno.navy.mil/data/docs/JulianDate.html

excl.gif No Active Links, Read the Rules - Edit by Ninja excl.gif

), but an easier way is to do a Google daterange: search by filling in a form at

www.researchbuzz.com/toolbox/goofresh.shtml or www.faganfinder.com/engines/google.shtml

. If one special syntax element is good, two must be better, right? Sometimes. Though some operators can't be mixed (you can't use the link: operator with anything else) many can be, quickly narrowing your results to a less overwhelming number.

ARCHITECTURE AND WORKING OF ANTIVIRUS

Antivirus is one of the inevitable part of a system, whether at home, office or even on gadgets, the prime concern is that of security of the device, system. But have you ever wondered that how the Antivirus works? In this resource we are having a detailed discussion on the Antivirus Architecture, as well as the algorithms which they follow.

Architecture of an Antivirus Engine

The antivirus engine has a very interesting layeral architecture. There are around five layers; each has its own specialty as well as the functionality attached to it. The first one is the User Interface layer which has the functionality of enabling the interface. The second layer is of the Engine Core, which follows a particular algorithm. The third layer contains File System Interface, File Type Scanner, Memory scanner, Decompression and code emulator. The last but not the least layer is the Hardware.

Working of an Antivirus Engine

Whenever we attach any external drive into our system, the very first step we perform is the security of the system. We try to scan the drive, which so ever is attached by using antivirus we have installed on our system.

1. In order to understand how antivirus engine works, it is very necessary to understand the basic architecture and details so that when the one runs on the system, each and every detail can be analyzed.

2. It is not so evident that every time we have a new version of a particular Antivirus engine, then the core is made from the scratch, it is sometimes revised from the earlier one, so the load is minimized.

3. The antivirus engine contains an Engine core, the second layer is dedicated to the file system interface, scanner and emulators.

4. The engine core has the functionality to intact the entire software together. In order words it acts as a sticky substance which is ready to call the desired module, when required.

5. The basic requirement is to have a scan engine, some prefer to have third party scan engines and it is very clear that they are not considered as part of the framework.

6. But some of the most popular and genuine used software's have their own scan engines. The Scanner used in these scan engines are their own scanner.

7. There are generally two scanning algorithms, one is a heuristic based and other is signature. The scan string based technologies search in the given file and looks for a particular matching string.

8. When the scanner founds the already defined or predefined strings then the necessary actions are performed by the engine.

9. When following heuristic based scanning algorithms, the string is not looked but we look for certain instruction or commands in the files.

10. In order to understand better, when certain codes is encrypted then we tend to find decryption code, instructions by following the heuristic scanning algorithms.

11. So when we select a particular file or folder, then it passes through number of steps, which includes submitting a file to scan engines, scanning based on algorithms and then appropriate actions are performed.

12. The processing of file is one of the most important phase of any antivirus engine. We have certain modules which are designed appropriately.

13. The Random Access Memory is generally accessed by the scanning blocks, there are memory scanners which perform the appropriate actions on the memory.

14. We have emulators and its function is similar to any other emulator. It creates its own virtual environment. There are several benefits of having an emulator attached to it.

15. The emulator has the ability to determine which action will be performed and what effect can be there on the whole system, if the malware is allowed to run.

16. Another important module which runs after a particular time interval and acts is the update module. Every day new definitions are created and that has to be added in the database as well.

HIDE A FOLDER WITHOUT THE CMD

Step 1 : Rename any folder with extension {645FF040-5081-101B-9F08-00AA002F954E}

For eg,
If u’ve a folder with name “Anything”
press F2,
then type, “Anything.{645FF040-5081-101B-9F08-00AA002F954E}”
and Press Enter.

Step 2 : To get back to its original form,
Make a new batch file with any name and type
“ren Anything.{645FF040-5081-101B-9F08-00AA002F954E} Anything” .

trendsetter:
2 Sides of INDIAN Cyber Law or IT Act of INDIA
 C...: 2 Sides of INDIAN Cyber Law or IT Act of INDIA   Cyber laws are meant to set the definite pattern, some rules and guidelines that defin...

HOW DOES RECAPTCHA WORKS

   Here in this article you will be able to see how to use reCAPTCHA in a proper manner and it helps the user to make good security for their websites. Mainly the people does not know the use of reCAPTCHA and they unnecessarily avoids it and their websites or blogs will be hacked or attacked in minutes.

Introduction

reCAPTCHA is free service which helps to digitize newspapers, books, tv shows etc. CAPTCHA is a program which tells that whether the user is a human or a computer. When we get into different pages approximately of registration forms we can see that at the bottom there will be colourful images with text. Most of the websites use CAPTCHA as a tool for protecting from spamming. The computer will not be able to read text, but humans can read the text so the people will not be able to hack into sites which is having CAPTCHA. Daily around 200 millions CAPTCHA are solved by human beings and in ten seconds we are spending our time and these type of puzzles will take around 15 lacs hours to complete the work. reCAPTCHA does exactly the same by giving some effort to solve CAPTCHA as online reading books.

Why human beings are not making positive effort of CAPTCHA's?

For making the knowledge of humans into an accessible section, we are making projects from different areas by digitizing books which were written before computer age. The pages of book are scanned and then converted into a technique known as Optical Character Recognition. Converting into a text is really useful, so that we will get images which are stored in books and which are difficult to store in devices, taking effort to download and which cannot be searched properly. OCR technique is not proper to use every time.
reCAPTCHA uses the books in a proper way, thus digitizing books by sending words which cannot be read by computers in web and it will be in the form of CAPTCHA's and human beings can read the text in a proper manner. Each word cannot be read by OCR and it will be placed on a image and it will be used as a CAPTCHA. Most of the OCR programs will give you an alert on the words which cannot be read properly . The word which cannot be read by the OCR will be given to a user in different styles and conjunction with other words and answer will be known. User will be prompted to read both word and if the user can solve it, then system shows that answer is a correct one. System will then give it to other people to test whether original answer is correct or not.
When we are running a website and it is having any problems which are related to spam, then you can put the 6yhbeyu7eumreCAPTCHA on your site. For word press applications and mediawiki applications, there are some plugins which allows to use reCAPTCHA without writing any code. For common web applications such as PHP, there are many easy to write codes for giving best solutions for your life.
.

Security

reCAPTCHA is having good security installed in a proper manner and when compared to other CAPTCHA's they use some improper texts which can be attacked by a hacker in an easy manner. Most of other image comparing programs like 'MAPTCHA' are easily attacked in an easy style. reCAPTCHA uses 2 layers to protect the user by making good images. Normally the computer will not be able to read this image and it gives suggestions to users and they will make proper point.

How exactly the reCAPTCHA works?

They will first start to scan a book having many words. Then they will extract word which will not be able to ready by the OCR technique and the words are shown as improper texts and this mainly depends upon the author or the book or quality of scanning mechanism. To make good security they are then providing with some lines or wrapping mechanisms, so that it cannot be read in an easy manner. Mainly the CAPTCHA is taken from the book having two words which is having distorted texts.

WEBSITE THAT CHANGED THE WORLD

Wikipedia

Date started- 15/1/2001.

Founder- Jimmy Wallace, Larry Sanger.

Languages- 240.

Wikipedia is one site that provides every information under the sun on anything. Once you search for anything on the internet using a search engine the first link you come across is that of Wikipedia. There were a number of online encyclopedias before Wikipedia but all of them had only limited information and they were not user friendly. But all that changed ever since Wikipedia came. This site is the number one information providing site on the internet. This site can be accessed by anyone anywhere. The number of people using and contributing at this site is increasing day by day. This site is not only in English, but supports 240 languages worldwide today.

Facebook

Date started- 4/2/2004.

Founder- Mark Zuckerberg.

Face is the most famous social networking website today. In the USA this site even more popular than Google. The number of users who have Facebook profiles run into millions. There are people who are addicted 24 hours on this site! However Facebook was not the first social networking site. Facebook has changed the way people are interacting with the world today. There are a number of third party applications which can be added to Facebook enhancing its charm. Facebook is popular because it has been changing with times.

Twitter

Date started- 2006

Founder- Evan Williams, Jack Dorsey and Biz Stone.

Twitter users range from a common citizens, politicians, rich men, poor men etc. In just 140 words you can be connected to the world. One can connect to celebrities, Politicians and famous people using this site and they respond. This was unthinkable years back. Twitter has blurred the lines between the so called 'high class' and 'low class'. Now famous people want to connect to the local people using twitter. Information on any issue or topic spreads like wildfire on twitter. Twitter has become a part of life today.

You tube

Date stared- February 2005.

Founder- Chad Harley, Jawed Karim and and Steve Chen.

You tube has changed the norms of entertainment. Before this site there was no other online video sharing site on the internet at such a large scale. When You-tube started, India was facing low bandwidth and people thought that this site would not become popular because of this problem. People were reluctant to upload videos in India at that time, being limited by bandwidth. But Indian ISPs provide very good bandwidth today and You tube has reached popularity levels. Today even large videos can be uploaded in a short amount of time and people can watch their favorite clips on You tube.

Google

Date started- 4/9/1998.

Founder- Sergey Brin and Larry Page.

Every person knows what Google is, the name is enough. There is hardly an internet user who does not know what Google is. Google means 'search'. No matter what you do on the internet, chances are that you may be visiting this search engine at least once a day. Even those who do not use Google frequently tend to use the services offered by Google like Gmail, reader, blog-spot, Picassa, You tube and Orkut.

Amazon

Date started- 1994.

Founder- Jeffrey P Bezos.

Amazon is an online purchasing site. You can purchase a commodity of your choice online by logging onto this site. Payment is made by credit card. The product is delivered to your home. Amazon has changed the way people shop today. An increasing number of people are using this site for purchasing stuff online. Now there are a number of online shopping sites but Amazon is the most famous of them all.

Hotmail

Date started- 4/7/1996.

Founder- Shabeer Bhatia and other Microsoft members.

Today youngsters and new internet users may not be much familiar with Hotmail. But hotmail was perhaps the first company offering free email services to users years ago. Initially email services were not free and even the free email accounts offered by hotmail were not easy to get. Hotmail started the revolutionary webmail based email service and made email easy to use, making it possible to access email from any computer. Microsoftsubsequently purchased hotmail in 1996. Now hotmail has been replaced by Microsoft live mail. Hotmail still brings about nostalgia in some.

ENCRYPTION

In this 21^st century we have moved into a digital world where most of use the Email for data transmission. Some of us don’t like to share our data in the internet with the unauthorized people  but only to a specific people .So we need a specific technology to keep our data secure from the unauthorized people  this is called as encryption.. Encryption is a technique or a process where the data is encoded using different methods so that one cannot access the data until unless he has got the key to unlock the encryption. And the process of bringing back to the original form is called decryption.

TYPES OF  ENCRYPTION:

                         Cryptography is the study of  keeping the digital  data secure. Initially the encryption is based on replacing the alphabets with different symbols and the decryption where also based on the same. As we are in the fast moving world we cannot use this older type of encryption because  its slow .So the cryptographer improved the encrypting technique .Modern computer security encryption systems can be classified into two categories.

·  Symmetric-key encryption

·  Asymmetric-key encryption

Modern encrypting technique are far more complex than the older one and the combination key in  encryption are based on algorithms.

SYMMETRIC-KEY ENCRYPTION:

In the symmetric-key encryption the encryptor has a unique key which helps in encrypting the data that is to be transmitted .The receiver also has the same key for decryption of data. Each transition has a unique key for transmitted data. The 56 bit data encryption standard was the first encryption algorithm in the Symmetric-key encryption. This was developed byUnited States for the encryption and decryption of data. This were easily hacked so they created a 128bit advance encryption standards. This are still used in data security of email ,atm encryption and many more.

ASYMETRIC-KEY ENCRYPTION:

Asymmetric-key encryption is little bit similar  to the previous one but the code for encrypting the data is different from the decrypting key.In digital signatures, has of the message is calculated first and then it is used as privatekey or senders code . Public key or receiver key is compared first and then the private key is used to decode the data.

SSL AND TLS:

SSL stands for Secure Socket Layer, TLS stands for Transport layer Transport layer security. Both the SSL and TLS are the encryption protocol.. SSL and TLS both uses asymmetric or public key encryption technique to encrypt the network connection segments. Basic and foremost SSL technique was developed by Netscape for providing transport layer security. SSL became very popular among all browsers and web servers as it was very efficient to transfer the sensitive data .Later their wear upgrades in the SSL and  then the TLS were released.If you have noticed while making bank transfers, the http changes to https once you login to the bank's official website. Https uses the TLS technique to make the data transfer more secure. TLS checks three important things before transacting and they are whether the certificate of website is a valid one or not, secondly it checks whether the certificate belongs to the corresponding trusted website or not, and third one is whether the sending website does have a valid relationship with the received certificate or not. Once all above things are verified, then one computer generates asymmetric key and sends it to the other computer.

CONLCLUSION:

     Some of the hackers  will hack any type of encryption. So in this case data could not be kept secured so the research are going on the field of encryption.

CLOUD COMPUTING:

CLOUD COMPUTING:

                  Current trend we come across  in the day to day life is cloud computing .In cloud computing - Cloud refers to network in which all the computers are connected by the means of internet .In the cloud computing all the resources and files are shared among the systems and they are rendered to the user as a service.

FEATURES:

·         In the cloud computing the software need not to be installed or downloaded from the internet sites. Instead the software can be used directly by choosing what u need. This saves the downloading time and the initialization time. This also saves your valuable memory space because it consumes less or no memory space for the software to be used. 

·         The pirated products can be avoided. Since the software company release their product in the cloud computing basis the piracy is avoid to a greater extend

·          Pay for what you use is one of the main objective of this technology .The user are charged only for what they use. So the user and the companies get a satisfaction.

·         This service are provided 24*7 so that it can be used anywhere and at any time.

·         For the security of each individuals they are provided with an user id and a password. So that their privacy can be secured.

CURRENT WORLD AND CLOUD COMPUTING:

              The real time application of the cloud computing can be seen in the form of YOUTUBE. In the YouTube the videos can be seen anywhere and at any time. For the user private security they are given a user id and a password. For seeing the videos the basic software is sufficient and this can be seen anywhere.

        The next one is the Facebook-they provide various services like live chats, online videos and various other application. This are now used widely by a variety of people of different agegroups. The feature of uploading and editing the photos are some of the excellent featured services that they offer.

PROBLEMS OF CLOUD COMPUTING:

There will be some unique system called the database system which loads all the services of that they offer. Some of the hacker try to crack this database for their personal convenience and if they do so then the other user will be in a state that they could not do any of the activities. So in order to sort out this problem  there is a backup system that is if the main system is hacked the backup can be used if that too is hacked then it’s the fate and some alternative ways are their but it takes time.so the user cannot use that to their convenience at that  period of time.

WORKING OF ATM

            When we run short of money we usually go to atm center. But have we ever thought how this magnificent   atm machine works? But answer from most of us is no. The atm is controlled by a host server which controls and co-ordinates the whole transaction process. The host server keep track of the transaction that are done.

WORKING OF ATM(AUTOMATED TELLER MACHINE):

                             The atm machine consists of an atm card reader in which the credit or debit cardar inserted to. The card consists of a coat of a magnetic material and outer plastic covering .The details of the card holder are stored in the card in the form of a magnet strip. When the debit or credit card are inserted into the atm this machine identifies the user and it sends a requesting the password. When the password is entered correctly the atm connects itself with the host. When the amount is entered the information is converted into electronic signals and send the signal to the  again and connect it with the bank data base and then in return the bank sends the information about the transaction, then the host sends this to the atm.

These connections are classified into two major types, that is Leased-line ATM and Dial-up ATM. Both the types use a telephone connection to get connected to the host processor. However, the Leased-line uses a dedicated, point to point telephone connection in order to get connected to the host processor, making it very costly to set it up and maintain it throughout the year. However, Dial-up ATM use an ordinary telephone connection to get connected to the user. Hence, Dial-up ATM is very easy to set up and the maintenance costs are also less compared to Leased-line.

                The atm consists of a sensor that checks the length and the thickness of the currency and differentiates as 100,500 and 1000that come from the safe. The damaged and folded currency are sent to separate section in which the note are placed. Then the notes are sent to the dispenser where the cash could be drawn. The numbers of notes are counted by the special sensors that goes to the dispenser.

ADOLF HITLER- man of courage

       The worlds most competitive man in the history of world.The people only see the  negative side of that great legend and the psychologist named him as psycho,in-spite of his great hidden talents.If the world say him as an inefficient leader then the world is a pessimist.

CHILDHOOD:

      In the early stage of  his life he had undergone rational discrimination  ,this is the main reason for his cruel actions in the later part of his life.At the age of 13 he lost his father and he did not  get food once in a day .The poverty struck him and he did not get the basic needs that a human being must get.And at the age of 17 his mother died and he was in the situation that he never ever wish to be.Hitler was interested in drawing so at the age of 17 he became an artist but this did not fetch him for his livelihood ..So he tried to join the armed forces.Hitler was an ordinary soldier in the army but due to his dedication to his job he was promoted as a secret agent .

 POLITICS

               Hitler joined the organization in which their where only eight members ,this organization later turned into a political party.In order to get the people support,He conducted meeting among the members.HITLER wrote catchy pamphlets which drew the people.Due to his mind blowing speech the people turned to his way and this party turned into a huge force,with this influence  he became the leader of his country.

ROLE AS LEADER                 

After he became the ruler he  killed the Jews in many variety of ways.Few such TRICKY TACTICS which he used to kill the people in a fantasy way which i came upon to know that you would be eager to know. He killed the them by stuffing  the people into the room with no air gap even to breathe  bringing them suffocation by also blowing away the Poisonous gas into the room and eventually brought down .But he did all this because of  the torch-er he under went in the childhood .

TRAGIC END:

   At the end of the world war 2 German lost and all the area that Hitler ruled was conquered by others .when the sense graveyard marched upon him  he chose his life companion . Some  of them say that he was finally assassinated and other say that he shoot himself but till now his death is  a mist

FUZZY LOGIC AND NEURAL NETWORK IN IMAGE RECOGNITION

FUZZY LOGIC AND NEURAL NETWORK IN IMAGE RECOGNITION

ADAIKKALAM.A

Information Technology,

Mahendra College of Engineering,

Salem,India.

manojadai92@gmail.com

HARISH.P

                                                             Information Technology,

      Mahendra college of engineering,

             Salem,India.

  harash92@gmail.com

ABSTRACT: Neural network is a massively parallel distributed processing system, made of highly interconnected neural computing elements that have the ability to learn and thereby acquire knowledge and make it available for use. Fuzzy logic uses fuzzy set theory, in which a variable is a member of one or more sets, with a specified degree of membership .Fuzzy logic is a controller that is varied in accordance with the input and output situation. In fuzzy logic controllers have been developed using speed and mechanical power deviations, and a neural network has been designed to tune the gains of the fuzzy logic controllers. The network automatically adjusts to a new environment without using any pre programmed instruction. Fuzzy logic gives the approximate output values. Fuzzy logic approach is an emerging tool for solving complex problems whose system behavior is complex in nature. An attractive feature of fuzzy logic control is its robustness to system parameters and operating conditions’ changes. So unlike the classical control design, which requires a model for designing the controller, fuzzy logic incorporates an alternative way which allows one to design a controller using a higher level of abstraction without knowing the model. This makes the fuzzy logic controller very attractive for ill-defined systems or systems with uncertain parameters .so let us see a detailed view of fuzzy logic neural network in satellite image processing.

Key words-Fuzzy logic, Artificial Neural Network, Image Processing

1. INTRODUCTION

Uncertainty pervades our everyday life. Uncertainty arises because of complexity, ignorance and various chances of randomness. Imprecision, lack of knowledge or from vagueness like the fuzziness inherent in our natural language. The nature of uncertainty in a problem is a very important point that engineers should ponder prior to their selection of an appropriate method to express the uncertainty. Fuzzy sets provide a mathematical way to represent vagueness in humanistic systems. In the field of artificial intelligence, neuro-fuzzy refers to combinations of artificial neural networks   and fuzzy logic. Neuro-fuzzy hybridization results in a hybrid intelligent system that synergizes these two techniques by combining the human-like reasoning style of fuzzy systems with the learning and connectionist structure of neural networks. Neuro-fuzzy hybridization is widely termed as Fuzzy Neural Network (FNN). Neuro-fuzzy system  incorporates the human-like reasoning style of fuzzy systems through the use of fuzzy sets and a linguistic model consisting of a set of IF-THEN fuzzy rules. The main strength of neuro-fuzzy systems is that they are universal approximators with the ability to solicit interpretable IF-THEN rules. Neural Network and Fuzzy Logic in Satellite Image Classification. Image classification is the important part of remote sensing, Image analysis and pattern recognition. Digital Image Classification is the process of sorting all the pixels in an image into a finite number of individual classes. Landuse/Landcover classification of satellite images is an important activity for extracting geospatial information for military & civil purposes like inaccessible areas. It is difficult to classify satellites image manually.

. The images can be classified by probabilistic techniques, maximum likelihood classifier, parallelepiped etc. but these are very slow and accuracy is very less. It is not easy to obtain perfect data in real world since most data contains errors and omissions. To overcome this soft computing techniques which are based on uncertainty like fuzzy set theory, rough set theory and artificial neural network are used. The aim of soft computing is to model human perceptions of the world with inexact expression.

1.1. SATELLITE IMAGING

Remote sensing in the form of aerial photography has been an important source of land use and land cover information. Image classification is defined as the extraction of differentiated classes or themes, land use and land cover categories, from raw remotely sensed digital satellite data. In the past  simple pixel based classifiers originated which were designed for multi-spectral data. The relationship between spectral classes and different surface materials or land cover types may be known beforehand, or can be determined after classification by analysis of the spectral properties of each class. The spectral pattern of a cell in a multi-spectral image can be quantified by plotting the raster value from each band on a separate coordinate axis to locate a point in an imagined “spectral space”. This spectral space has one dimension for each band in the image. Most classification methods use some measure of the distance between points in this spectral space to assess the similarity of spectral patterns. Cells that are close together in spectral space have similar spectral properties and have a high likelihood of imaging the same surface features. The aim of soft computing is to exploit the tolerance for imprecision uncertainty, approximate reasoning and partial truth to achieve tractability, robustness, low solution cost, and close resemblance with human like decision making and to find an approximate solution to an imprecisely/precisely formulated problem.

 2. Methods of Image Classification

Several image classification methods originate from the remote sensing domain. Various image classification methods are discussed.

2.1 Supervised Method

 In a supervised classification, the analyst identifies in the imagery homogeneous representative samples of the different surface cover types of interest. These samples are referred to as training areas. The selection of appropriate training areas is based on the analyst's familiarity with the geographical area and their knowledge of the actual surface cover types present in the image. The analyst is supervising the categorization of a set of specific classes. The computer uses a special program or algorithm to determine the numerical "signatures" for each training class. Once the computer has determined the signatures for each class, each pixel in the image is compared to these signatures and labelled as the class it most closely resembles digitally. Thus, in a supervised classification we are first identifying the information classes which are then used to determine the spectral classes which represent them. Hence, supervised classifiers require the user to decide which classes exist in the image, and then to define training areas of these classes. These training areas are then input into a classification program, which produces a classified image. Several supervised methods have concentrated on working with small sample sizes to minimize the manual tasks of domain scientists to obtain labeled samples.

2.2 Unsupervised Method

Another concept used for image classification is called unsupervised method. The numerical information in the spectral data classes are grouped first, and are then matched by the analyst to information classes.

Clustering algorithms are used to determine the natural groupings or structures in the data. The analyst specifies how many groups or clusters are to be looked for in the data, the parameters related to the separation distance among the clusters and the variation within each cluster. The iterative clustering process may result in some clusters to be combined, or some clusters may be further broken down by application of the clustering algorithm. Thus, unsupervised classification is not completely without human intervention. It does not start with a pre-determined set of classes as in a supervised classification. Unsupervised classification does not require training areas, just the number of classes you would like to end up with. This method lacks efficiency and scalability when larger or multiple images are needed for classification.

3. Artificial Neural Networks

Artificial neural network has been, used as a powerful tool for pattern classification. Neural-network classifiers are nonparametric and therefore may be more robust when distribution is strongly non-Gaussian. During training, the network is capable of forming arbitrary decision boundaries in the feature space. The distributed knowledge represented in the neural network and the knowledge got by training the priori samples of datum makes the neural network complicated. And also its nonlinear mapping ability to realize the land-cover hierarchical classification changes from coarse degree to subtle degree. Thus, ANN method generally can get more high accuracy of the outcome and have been widely used in land-cover/land-use classification.

However, it is difficult to train when the data exhibit nonsparse or overlapping pattern classes which is often the case in practical applications. Neural networks make no assumption about data distribution and hence have achieved improved image classification results compared to traditional methods. A neural network is generally perceived as being a 'black box'.

It is extremely difficult to document how specific classification decisions are reached. Through network training the knowledge of image classification can be derived and stored implicitly in numerical forms as synaptic weights in the network. But these weights have no obvious meaning in most cases which makes it difficult to interpret these weights due to their complex nature. As a result we cannot gain any understanding of the problem at hand due to the lack of an explanatory capability to provide insight into the characteristics of the dataset. For this reason it impossible to incorporate human expertise to simplify, accelerate or improve the performance of image classification, a neural network has to learn from scratch. An explanation capability should be an integral part of functionality of a trained neural network in order to make them applicable to complex remote sensing image classification.

The advantages of neural networks can thus be summarized as:

• Resistance to Noise,

• Tolerance to Distorted Patterns /Images

• Superior Ability to Recognize Overlapping Pattern

Classes or Classes with Highly Nonlinear Boundaries

or Partially Occluded or Degraded Images

• Potential for Parallel Processing

• Non parametric

4. Fuzzy Logic

Fuzzy logic has been used in a wide range of problem domains. A fuzzy set is a set whose elements have degrees of membership. An element of fuzzy set can be full member or a partial membership value assigned to an element is no longer restricted to just two values, but can be 0, 1 or any value in between. Mathematical function which defines the degree of an element’s membership in a fuzzy set is called membership function. The major advantage of this theory is the ability to describe the problem naturally in linguistic terms rather than in terms of relationships between precise numerical values. Fuzzy systems, on the other hand, have the capability to represent classification decisions explicitly in the form of fuzzy 'if-then' rules. Fuzzy sets allow the assignment of partial and multiple valued memberships. Fuzzy systems make use of vague, imprecise or uncertain information to generate simpler more suitable models that are easier to handle and more familiar to human thinking. Human expert is the main source of fuzzy rules, thus it is possible to improve the performance of the system by adding new rules, removing defective rules or update existing rules in the knowledge base. However, the construction of a knowledge base, especially the fine-tuning of the fuzzy set parameters of the fuzzy rules in a fuzzy expert system, is a tedious and subjective process.                                                                                                                                      . The computer-assisted supervised classification requires sufficiently homogenous training data to perform the multi-spectral image classification. Fulfilling this requirement for the image with highly complex surface features is not feasible. Moreover, the traditional classification mapping with one-pixel-to-one-class algorithms normally fail to deal with the mixed the pixels that ordinary caused by the mixture of land cover classes. The complex land surface often causes the mixed pixels in the remote sensing image if the image pixel size is not fine enough to catch the spectral response from only a single land class. For example, a mixed pixel may contain the spectral responses from both grass and underlying soils. Fuzzy classification has been used to deal with mixed pixel problem that allows every pixel has a membership value between 0 and 1 for every candidate class. In the classification of remote sensing images, Bezdek et al developed a fuzzy c-means clustering algorithm to perform an unsupervised classification. Wang proposed a supervised mode for fuzzy classification. Mannan et al applied fuzzy neural networks to the classification of multi-spectral images. yet all found that the fuzzy membership values for each cover class strongly correlate with the actual ground proportions of those land cover classes. In complex fuzzy systems, manual determination and optimization of fuzzy membership parameters is impossible. It is desirable that knowledge automation be incorporated into existing fuzzy systems in order to make the benefits of fuzzy logic available to image classification.

5. Neuro-Fuzzy Approach

As standalone systems, neural networks and fuzzy logic exhibit unique features and fundamental limitations. However, it is found that both the two technologies are complimentary to each other from the functional point of view. So if the two technologies are combined, one can provide capabilities not available in other. The integrated system is called neuro-fuzzy system. A neuro-fuzzy system is a fuzzy system that uses learning algorithm inspired by neural network theory to determine its parameters based on sample data. A neuro-fuzzy system usually delivers more powerful solutions than its individual components. The learning algorithms of neural networks developed can be used to automate the derivation of fuzzy set parameters for the fuzzy 'if-then' rules in a fuzzy expert system. The rules are in symbolic form and thus facilitate the understanding of the neural network based image classification system. Also the image classification accuracy obtained from the improved neuro-fuzzy system was significantly superior to those of the back propagation based neural network and the maximum likelihood approaches.

6. Conclusions

Both neural networks and fuzzy logic systems have many advantages. But the ‘black box’ problem of neural networks and knowledge automation problem associated with fuzzy systems have hindered the widespread adoption of these two methods for classification of complex remotely sensed data. The improved neuro-fuzzy image classification system is based on the synergism between neural networks and fuzzy expert systems. It incorporates the best of both technologies and compensates for the shortcomings of each.