Sharif Digital Repository

In this chapter, a method is proposed to contact the Police with mobile phones and via SMS (Short Message Service). In this method, when a person wants to contact the Police, he must only press a special key on his mobile phone for a short time to launch a special program. This program sends current location of the person using GPS system and sends it periodically with other useful information such as name, home and work address of that person automatically to the Police Station using SMS. In this method, there is no need to talk and a person can contact the Police easily and tell them the place which crime has occurred. In addition, there is no busy line problem. This method has low cost... 

Nowadays, a great amount of information is circulated through the Internet. Some of them exclusively belongs to a special group of users and requires protection and safeguarding against unauthorized access. To this end, a category of systems called HIP (Human Interactive Proof) have been introduced to distinguish between various groups of users. CAPTCHA (Completely Automatic Public Turing Test to Tell Computer and Human Apart) methods are one of the important branches of HIP systems which are used to distinguish between human users and computer programs automatically. These methods are based on Artificial Intelligence (AI) topics. The goal of these systems is to ask questions which human... 

By expanding communication, in some cases there is a need for hidden communication. Steganography is one of the methods used for hidden exchange of information. Steganography is a method to hide the information under a cover media such as image or text. One of the text steganography methods for Persian and Arabic texts is "La" steganography method. But that method increases the file size and changes the apparent of the text. In this paper a method for solving these problems is proposed. In Persian and Arabic, each letter can have four different shapes regarding to its position in the word. In this method by using this feature of Persian and Arabic languages and the way which documents are... 

The Multimedia Messaging System (MMS) allows a user of a mobile phone to send messages containing multimedia objects, such as images, audio or video clips. On the other hand establishing hidden communication is an important subject of discussion that has gained increasing importance nowadays with the development of the Internet. One of the methods introduced for establishing hidden communication is steganography. Therefore steganography in MMS is an interesting idea. One of the problems in steganography methods is the security of transferring password key used for steganography between sender and receiver of secure data. In this paper a new method is proposed for solving this problem using... 

One of the services used in mobile phone is the short message service (SMS) which is widely used by the public in all parts of the world especially in Asia and Europe. This service enables people to write and exchange short messages via mobile phone. Due to the limited size of SMS, lack of a proper keyboard on the mobile phone and to improve the speed of typing, new abbreviations have been invented for different words and phrases which has lead to the invention of a new language called SMS-Textlng. One of the main issues in communication is information security and privacy. There are many methods for secret communication and many researchers are working on steganography. In steganography the... 

Mobile banking (M-Banking) has been welcomed in most of the countries as a new branch in electronic banking (E-Banking). In developing countries such as Iran mobile banking is limited to fields such as SMS due to lack of infrastructure and because of high costs. In this paper we present a method for developing banking services through mobile phone in the bank area. In our method a server which is capable to be connected through bluetooth is installed in the bank and offered banking services. Customers inside the bank and also around the bank are connected to the bank system through bluetooth technology and handle their banking operations through their mobile phones. This way they won't pay... 

Digital music technologies enable users to create and use large collections of music. One of the desirable features for users is the ability to automatically organize the collection and search in it. One of the operations that they need is automatic identification of tracks' artists. This operation can be used to automatically classify new added tracks to a collection. Additionally, the user can use this operation to identify the artist of an unknown track. The artist name of a track can help the user find similar music. In this paper, we introduce a fast and scalable system that can automatically identify the artist of music tracks. This system is creating a signature for each track that is... 

Clustering is a major task in data mining which is used in many applications. However, general clustering is inappropriate for many applications where some constraints should be applied. One category of these constraints is the cluster size constraint. In this paper, we propose a new algorithm for solving the clustering with balancing constraints by using the minimum matching. We compare our algorithm with the method proposed by Banerjee and Ghosh that uses stable matching and show that our algorithm converge to the final solution in fewer iterations. ©2009 IEEE  

Today, the Internet is used to offer different services to users. Most of these services are designed for human users, but unfortunately some computer programs are designed which abuse these services. CAPTCHA (Completely Automated Public Turing test to tell Computers and Human Apart) systems are designed to automatically distinguish between human users and computer programs and block such computer programs. Most of current CAPTCHA methods are using visual patterns and hence blind users cannot use them. In this paper, we propose a new CAPTCHA method which is designed for blind people. In this method, a small sound clip is played for the user and he/she is asked to say a word. Then the user...