Concealed Data in Two Way Text Messaging: A Framework for Interactive Mobile Learning Environment

Transcription

1 Concealed Data in Two Way Text Messaging: A Framework for Interactive Mobile Learning Environment H K Salinda Premadasa Sabaragamuwa University of Sri Lanka

2 Introduction Short Messaging Service (SMS) is one of the best qualitative mediating tools adopted in the arena of mobile communication pedagogically, economically and technologically More than 6.6 trillion SMSs were sent out over carrier networks worldwide in the year 2010 (

3 Introduction The use of mobile technologies for distance learning has become a popular tool in higher education across the globe due to its everincreasing demand for student-centric learning The teacher and the student are crucial entities in the learning process Moreover, supporting students in teaching is considered as an indirect form of supporting a student s learning ability

4 Theoretical Background A standard SMS does not fully support two-way texting when there is a necessity to include a part of the message received in the reply body SMS Centre (SMSC) performs a store and forward mechanism for sending and receiving text messages Mobile Originated (MO) text Message Sender SMSC Mobile Terminated (MT) text Message Receiver

5 Theoretical Background The MO-text message is transferred from a mobile phone to SMSC by composing it with SMS-SUBMIT PDU format Similarly, an MT-text message is received at a mobile phone in SMS-DELIVER PDU format from the SMSC SMS-SUBMIT Protocol Description Unit (PDU)

6 Theoretical Background SMS-OCTETS Field Name Length (bytes) Description 06 Address Length 1 number of octets to follow 91 Type of address 1 SMSC number format (international format) F3 Address value variable address of an SMSC ( ) 41 First octet of SMS- SUBMIT 1 This Means User Data Header (UDH) turned ON 00 TP-MR 1 ID assigned to a SMS in SMS-SUBMIT format by a local GSM modem 0A Address Length 1 number of digits in the destination mobile number 81 Type of address 1 destination phone number format (national format) Address value Variable destination phone number ( ) 00 TP-PID 1 informs about networking protocol and nature of SMS data 00 TP-DCS 1 user data encoding scheme A7 TP-VP 1 validity period (amount of time that the SCA will hold submitted SMS if the destination address is unreachable 15 TP-UDL 1 size of the user data (payload) 06 (05) TP-UDHL 1 user data header length (Depicts in a Table 2) C ( ) TP-UDH Variable user data header (Depicts in a Table 2) 54747A0E4ACF B5C BF379F85C06 TP-UD Variable user data (PDU message), 19 octets = 21characters (TP-UD can be up to 140 octets = 160 characters maximum)

7 Theoretical Background Fields Description User Data Header Length (UDHL) Information Element (IE) C350 User Data Header Length -UDHL(06 octets contained in this UDH) IEI: Application Port Addressing Scheme (16 bit address) Information Element Data Length (IEDL): Indicates the number of fields in UDH Mobile Handset Destination Port (Port 50000) 0000 Originating Port (Port 0) Table 2: Fields of User Data Header (UDH) Port Number Addressing

8 Theoretical Background The text message architecture with UDH can be summarized as follows

9 System function and architecture The proposed system is a Moodle LMS integrated system It enables a teacher to post text messages to students to establish a news forum via a mobile browser interface through an Internet-enabled mobile device. The text message received by a student contains the course code generated automatically by the system in the message body itself.

10 System function and architecture This course code information is extremely important to the recipient to identify from which course the message originated from as several courses are available in the LMS The recipient is able to send a reply to the relevant course unit These reply messages are initially delivered to a database to be categorized depending on the course unit (course code) by the system

11 System function and architecture Teacher inserted and system sent messages No Course Unit News News (teacher logged) (inserted by the teacher) (received by the student) 1 ML 001 News Forum Started! <<ML 001>> News Forum Started! 2 BM 221 The conference has been called <<BM 221>> The conference has on March 2013! on March 2013! 3 IT 324 IT workshop held on the <<IT 324>> IT workshop held on tomorrow the faculty Students replied back and system received messages No Reply News (inserted by the student) Reply News (received by the system) 1 Sir. I have prepared an article for it <<BM 221>> Sir. I have prepared an article for it 2 Thanks! <<ML 001>> Thanks! 3 We are ready madam <<ML 001>> We are ready madam 4 Fantastic! I have been waiting 4 it <<BM 221>> Fantastic! I have been waiting 4 it 5 It is easy to handle! <<ML 001>> It is easy to handle! 6 Dear friends. It is important 4 exams! <<IT 324>> Dear friends. It is important 4 exams!

12 System function and architecture

13 System function and architecture

14 Results and Discussion The proposed algorithm is tested with 100 SMSs sent by the system to a series of smart phones as well as basic phones (i.e. Nokia 5800, 6720, 3120, 6210) Having connectivity to several GSM networks (GSM provider I 38 SMSs, GSM provider II 28 SMSs, GSM provider III 20 SMSs and GSM provider IV 14 SMSs).

15 Results and Discussion These SMSs are delivered continuously within 342 seconds through the SMS gateway without any significant time variations and interruptions

16 Conclusion The proposed framework provides a more flexible and convenient way of passing messages between the users than a traditional web-based E-learning platform. Proposed two-way texting mechanism will certainly provide an ideal opportunity not only in the education sector but also in other sectors, which is using concealed data with bulk text messages via a single phone number.

17 THANK YOU!