Sharif Digital Repository

Nowadays development of cell phone network provides huge and ubiquitous data, with wide application in transportation science. One of the most important advantages of these kinds of data is enabling the process of collecting information without any active users' interference. A big data set consisting of 300,000 cell phone users' information in Shiraz are studied. This data set includes spatiotemporal information of travelers for every 5 minutes in a time span of 40 hours in two consecutive days. The spatial part of each user's information contains the position of the BTS (Base Transceiver Station) to which his cell phone is currently connected. Due to the existence of outliers, it is... 

The tendency towards using activity-based models to predict trip demand has increased dramatically over recent years, but these models have suffered insufficient data for calibration. This paper discusses ways to process the cellphone spatio-temporal data in a manner that makes it comprehensible for traffic interpretations and proposes methods on how to infer urban mobility and activity patterns from the aforementioned data. Movements of each subscriber is described by a sequence of stays and trips and each stay is labeled by an activity. The type of activities are estimated using features such as land use, duration of stay, frequency of visit, arrival time to that activity and its distance... 

After expanding the use of computer and its affect on different aspect of life, the copyright issue has gained many attractions. For this purpose watermarking methods are proposed. In these methods a code is embedded into digital material that can be used to approve ownership, it can be visible or invisible to the user. On the other hand with the rapid growth of mobile phones, mobile telecommunication companies starting to add additional features to their mobile phones such as MMS (Multimedia Messaging Service) in order to attract more customers. MMS is a technology that allows mobile phones sending messages that includes multimedia objects esp. images. For copyright protection of images... 

In last 20 years, the Internet and mobile communication growth in parallel. There are many sites specially designed for mobile phones that users must enter username and password to enter them. In this paper we introduce a new method based on CAPTCHA which does not require entering any password. Instead of entering the password, an image of a number is shown to the user and he/she must type it. The user response is coded with his/her mobile phone IMEI and sent to the server. The server checks user's response according to user's IMEI and if it was correct, let the user to enter the site, so there is no need to enter any password. This method has been implemented in PHP and J2ME languages and... 

This study focuses on the mode classification of phones speaker modes using GMM 1. In this regard, speech data in both enabled and disabled speaker modes of cell phones and telephones were collected, processed and classified into two different categories. The different mixture numbers (1 to 4) of GMM and wave files sizes of 10, 20, 40 and 80 kb were tested in order to obtain an optimal condition for classification. The GMM method attained 87.99% correct classification rate on test data. This classification is important for speech enabled IVR 2 systems [1], dialog systems and many systems in speech processing in the sense that it could help to load an optimum model for increasing system... 

Mobile value-added services have drawn the attention of researchers and practitioners recently, due to the rapid development of the mobile telecommunications market. Various mobile-based services and applications have therefore been introduced in order to satisfy mobile phone subscribers' needs. Facing intensive competition, service providers are eager to persuade mobile phone subscribers into using the mobile value-add services in the hope to expand market share and ultimately raise revenues. This study therefore intends to investigate the factors that influence mobile phone subscribers' intention to use mobile value-added services in Iran by incorporating quality factors and perceived... 

Security in mobile handsets of telecommunication standards such as GSM, Project 25 and TETRA is very important, especially when governments and military forces use handsets and telecommunication devices. Although telecommunication could be quite secure by using encryption, coding, tunneling and exclusive channel, attackers create new ways to bypass them without the knowledge of the legitimate user. In this paper we introduce a new, simple and economical circuit to warn the user in cases where the message is not encrypted because of manipulation by attackers or accidental damage. This circuit not only consumes very low power but also is created to sustain telecommunication devices in aspect... 

We describe our work on incorporating probabilities of phone durations, learned by a neural net, into an ASR system. Phone durations are incorporated via lattice rescoring. The input features are derived from the phone identities of a context window of phones, plus the durations of preceding phones within that window. Unlike some previous work, our network outputs the probability of different durations (in frames) directly, up to a fixed limit. We evaluate this method on several large vocabulary tasks, and while we consistently see improvements inWord Error Rates, the improvements are smaller when the lattices are generated with neural net based acoustic models. Copyright © 2017 ISCA  

SMS (Short Message Service) is a popular service for transferring and exchange of short text messages between mobile phones. MMS (Multimedia Messaging Service) is another technology in mobile phones for creating, sending, receiving and storing messages that include text, images, audio and video clips. But MMS is not available in some countries. So, we cannot send images in those countries by mobile phones. In this paper, we present a method for solving this problem. In this method, the image is converted to a text file by using Base64 encoding and it is sent through several SMS messages  

Sudoku puzzle is a logical game which has recently got very popular. Every day various mass media print these puzzles. As a result these puzzles are a suitable alternative for hidden data transfer. SMS (short message service) is one of the popular mobile-phone services. In this service people can write short messages and send it to each other through mobile phones. In this paper a method has been presented for Steganography (hiding data) in Sudoku puzzles and through SMS. In this method after hiding data in a Sudoku puzzle, the puzzle is sent in a way that it does not attract any attention. Steganography algorithm is based on order of place of numbers 1 through 9 in one of the specified row... 

This paper presents a novel patchwork audio watermarking scheme with a psychoacoustic model of HAS in DFT domain that has significantly higher detection robustness compared to standard and modified patchwork watermarking algorithms. In addition, watermark is perceptually tuned, so that its embedding is transparent. The proposed algorithm can be used for transmitting hidden data through telephone channel. Experimental results show that the proposed watermarking algorithm is sustainable against compression algorithms such as MP3, LPF, resampling, requantization and AWGN attacks. © 2008 IEEE  

Nowadays m-banking (mobile banking) is widely used in many banks. It has embarked upon supply of various services based on different systems and with the aid of various services such as the Short Message Service (SMS). However in developing countries such as Iran, m-banking is facing some challenges. One of these challenges is the issue of language of this system, because the main language of this system, in both side of bank system and customer mobile phone, is English. Also one of the main issues in m-banking services is the security of the systems. For solvin g the above problems, we proposed a method in this paper. By this method we send secure banking messages as well as Persian SMS for... 

There are many websites specially designed for mobile phones. Some hackers write automated programs to abuse these website services and waste the website resources. Therefore, it is necessary to distinguish between human users and computer programs. Methods known for achieving this are known as CAPTCHA (Completely Automated Public Turing test to tell Computers and Human Apart). CAPTCHA methods are mainly based on the weaknesses of OCR (Optical Character Recognition) systems and ask the user to type a word. So using them is difficult in tools such as PDAs (Personal Digital Assistant) or mobile phones that lack a complete keyboard. In this paper, a new CAPTCHA system is proposed for... 

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... 

After rapid growth of the Internet, establishing hidden communication is an important subject of security that has gained increasing importance. One of the methods for establishing hidden communication is steganography. On the other hand with the expanding the use of mobile phones mobile telecommunication companies starting to add additional features to their mobile phones such as MMS (Multimedia Messaging Service) in order to attract more customers. Considering above statements, steganography in MMS messages is a good solution for establishing hidden communication. In this paper a new method for steganography in MMS messages using both text and image steganography methods is presented. This... 

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... 

Now we are able to offer numerous softwares for mobile phones after the advances in mobile phone industry. Most of these softwares should be bought in order that we can use them. Some of these softwares are sharewares and after buying them you have to insert an activation code given by the manufacturing company based on your mobile IMEI code in order to activate the software. In this paper a new method is introduced for sending the mobile software activation code by SMS (Short Message Service). In this method the activation code is hidden in an SMS picture message by steganography method and sent to the user. The software extracting the activation code from the picture and compare it with... 

Recently Mobile Learning (M-Learning) has attracted much attention. Due to advantages of SMS (Short Messaging Service) on mobile phones we present a safe and protected method for taking multiple-choice quizzes by using the SMS on mobile phones in this paper. In this method questions of quiz are sent to students along with their answers through some SMS messages. The students will receive their grades immediately after answering the questions and this grade is also sent to the instructor or professor along with the student's answers through an SMS Picture Message. Answers of questions and the student's grade are hidden in SMS picture message through stenography and then they are sent. The... 

Now we are able to offer numerous softwares for mobile phones after the advances in mobile phone industry. Most of these softwares should be bought in order that we can use them. Some of these softwares are sharewares and after buying them you have to insert a serial number given by the manufacturing company in order to activate the software. But the crackers reproduce them illegally by cracking the software. One of the tactics used by crackers for finding the serial number of the softwares is brute force attacks. In this paper a method based on CAPTCHA (Completely Automated Public Turing Test to tell Computer and Humans Apart) is proposed for solving this problem. In this method while... 

There are many sites specially designed for mobile phones. In cases such as the registering in websites, some hackers write programs to make automatic false enrolments which waste the resources of the website. Therefore, it is necessary to distinguish between human users and computer programs. These systems are known as CAPTCHA (Completely Automated Public Turing test to tell Computers and Human Apart). CAPTCHA methods are mainly based on the weak points of OCR (Optical Character Recognition) systems while using them difficult in tools such as PDAs (Personal Digital Assistant) or mobile phones that lack a big keyboard. So the Non-OCR-Based CAPTCHA methods are proposed which are do not need...