DIRECTORATE OF TECHNICAL EDUCATION, CHENNAI-25 DIPLOMA EXAMINATIONS-APRIL-2019 DEPT : COMPUTER ENGINEERING SUBJECT : MOBILE COMPUTING QCODE/SUB CODE : 915/35262 PART -A 1. Define LAN.[ 2 marks] A local-area network (LAN) is a computer network that spans a relatively small area. Most often, LAN is confined to a single room, building or group of buildings, however, one LAN can be connected to other LANs over any distance via telephone lines and radio waves. 2. What is meant by Adhoc? [ 2 marks] An ad hoc network is a network that is composed of individual devices communicating with each other directly. The term implies spontaneous or impromptu construction because these networks often bypass the gatekeeping hardware or central access point such as a router 3. What is GSM network? [ 2 marks] GSM stands for Global System for Mobile Communication. GSM is the most widely accepted standard in telecommunications and it is implemented globally. It is a digital cellular technology used for transmitting mobile voice and data services. 4. Write the limitation of GPRS. [ 2 marks] Although GPRS will provide better data rates than is currently available, there are some limitations. • Speeds of 177.2kbps would require a user to use all eight timeslots without any error protection - which simply won't happen. Initial terminals are likely to use only 1-3 timeslots anyway, limiting the available bandwidth to a GPRS user. • When GPRS packets are sent to a destination they are sent in all different directions - allowing for the potential for one or some of those packets to be corrupted or even lost altogether during the data transmission over the radio link. This is inherent in wireless packet technologies so data integrity and retransmission strategies are incorporated - which in turn result in potential transit delays. 1 Although available radio resource can be concurrently shared between several users, an increase in the numbers of users will slow data services down for each user. 5. Define DVM. [ 2 marks] The Dalvik Virtual Machine (DVM) is an android virtual machine optimized for mobile devices. It optimizes the virtual machine for memory, battery life and performance. The Dalvik VM was written by Dan Bornstein. The Dex compiler converts the class files into the . dex file that run on the Dalvik VM. 6. Define auto completes text view. [ 2 marks] Auto complete Text View is an editable text view that shows completion suggestions automatically while the user is typing. The list of suggestions is displayed in a drop down menu from which the user can choose an item. 7. What is the uses of grid view? [ 2 marks] Android GridView. Android GridView layout in one of the most useful layouts in android. GridView is mainly useful when we want show data in grid layout like displaying images or icons. This layout can be used to build applications like image viewer, audio or video players in order to show elements in grid manner. 8. What is meant by SQLite? [ 2 marks] SQLite is a software library that implements a self-contained, serverless, zero- configuration, transactional SQL database engine. SQLite is the most widely deployed SQL database engine in the world. The source code for SQLite is in the public domain. This tutorial will give you a quick start with SQLite and make you comfortable with SQLite programming. PART-B 9. What is meant by mobile computing? [ 3 marks] Mobile Computing is a technology that allows transmission of data, voice and video via a computer or any other wireless enabled device without having to be connected to a fixed physical link. The main concept involves − Mobile communication Mobile hardware Mobile software 2 10. List out the application of tier-2,tier-3. [ 3 marks] Application (Tier-2) • This layer plays an important role in wireless LAN applications. • It aces as interface between the Presentation Layer and the Data Layer. • It processes the user input, obtains the information and makes the decisions. • It uses the technologies like .NET, JAVA, ZEND. Data (Tier-3) • Data layer includes the database systems in which the processed data can be stored and retrieved. 11. Describe about CDMA. [ 3 marks] . Code Division Multiple Access (CDMA) is a digital cellular technology used for mobile communication. CDMA is the base on which access methods such as cdmaOne, CDMA- 2000, and WCDMA are built. The CDMA is a digital modulation and radio access system that acts as a signature codes to arrange simultaneous and continuous access to a radio network by multiple uses. CDMA cellular systems are deemed superior to FDMA and TDMA, which is why CDMA plays a critical role in building efficient, robust, and secure radio communication systems 12. Discuss any three strengths of SMS. [ 3 marks] The following are the Strength of SMS Always Connected As SMS uses the SS7 signaling channel for its data traffic, the bearer media is always on. Users cannot switch OFF, BAR or DIVERT any SMS message. SMS message is delivered to the Mobile Station without any interruption to the ongoing call. Self Configurable and last mile problem resistant SMS is self configurable and subscriber is always connected to the SMS bearer irrespective of the home and visiting network configuration. Asynchronous 3 SMS is completely an Asynchronous. In case of SMS, even if the recipient is out of service the transmission will not be abandoned and the particular SMS will be placed in the message queue. 13. Explain reverse geocoding. [ 3 marks] Android Geocoding refers to transforming street address or any address into latitude and longitude. Reverse Geocoding refers to transforming latitude and longitude into its corresponding street address. Address class helps in fetching the street address, locality, sub-locality, city, country, landmark etc. features of the location. 14. Explain about the option menu and context menu. [ 3 marks] A context menu (also called contextual, shortcut, and pop up or pop-up menu) is a menu in a graphical user interface (GUI) that appears upon user interaction, such as a right-click mouse operation. A context menu offers a limited set of choices that are available in the current state, or context, Android Option Menus are the primary menus of android. They can be used for settings, search, delete item etc. 15. Explain about the android SDK and ADT. [ 3 marks] The Android SDK (software development kit) is a set of development tools used to develop applications for Android platform. The Android SDK includes the following: Required libraries Debugger An emulator Relevant documentation for the Android application program interfaces (APIs) Sample source code Tutorials for the Android OS ADT 4 ADT (Android Developer Tools) is a plugin for Eclipse that provides a suite of tools that are integrated with the Eclipse IDE. It offers you access to many features that help you develop Android applications quickly. ADT provides GUI access to many of the command line SDK tools as well as a UI design tool for rapid prototyping, designing, and building of your application's user interface 16. Write a note on calling build in applications. [ 3 marks] Android provides Built-in applications for phone calls, in some occasions we may need to make a phone call through our application. This could easily be done by using implicit Intent with appropriate actions. Also, we can use PhoneStateListener and TelephonyManager classes, in order to monitor the changes in some telephony states on the device. PART-C 17. (a) Explain the architecture of mobile computing tier 1,2. [Description- 7marks, diagram -3 marks] A 3-tier architecture is an application program that is organized into three major parts, comprising of: • The data access layer tier at the bottom, • The application tier (business logic) in the middle and • The client tier (presentation) at the top. Each tier is distributed to a different place or places in a network. These tiers do not necessarily correspond to physical locations on various computers on a network, but rather to logical layers of the application. 5 1. Presentation Layer (UI): • This layer presents data to the user and optionally permits data manipulation and data entry, also this layer requests the data form Business layer. • This layer accomplished through use of Dynamic HTML and client-side data sources and data cursors. 2. Business Logic Layer: • The business logic acts as the server for client requests from workstations. It acts according Business rules fetch or insert data through the Data Layer. • In turn, it determines what data is needed (and where it is located) and acts as a client in relation to a third tier of programming that might be located on a local or mainframe computer. 6 • Because these middle-tier components are not tied to a specific client, they can be used by all applications and can be moved to different locations, as response time and other rules require. (OR) (b) Explain about the wireless LAN and its application.write the features of WI-FI and WI-MAX. [Description- 10marks] Wireless Network Wireless LAN stands for Wireless Local Area Network. It is also called LAWN (Local Area Wireless Network). WLAN is one in which a mobile user can connect to a Local Area Network (LAN) through a wireless connection. The IEEE 802.11 group of standards defines the technologies for wireless LANs. For path sharing, 802.11 standard uses the Ethernet protocol and CSMA/CA (carrier sense multiple access with collision avoidance). It also uses an encryption method i.e. wired equivalent privacy algorithm. Wireless LANs provide high speed data communication in small areas such as building or an office. WLANs allow users to move around in a confined area while they are still connected to the network.