CSE476 Mobile Application Development. Yard. Doç. Dr. Tacha Serif Department of Computer Engineering Yeditepe University

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1 CSE476 Mobile Application Development Yard. Doç. Dr. Tacha Serif Department of Computer Engineering Yeditepe University Fall 2013 Yeditepe University 2013 Outline Context-awareness background The idea What is context Operational Definition Categories of context Design Principles User activities Context-aware application examples Usability Failures How to maintain usability? Case Study: Evaluation of Context aware Tour Guides CSE476 Mobile Application Development Yeditepe University Page 2 1

2 Context awareness background Ubiquitous computing in early 90s: computing everywhere and invisible Implication Create applications that work seamlessly in human environments Understanding of context CSE476 Mobile Application Development Yeditepe University Page 3 The Idea Question: How do we effectively infer characteristics of situations and usefully supplement them with technology CSE476 Mobile Application Development Yeditepe University Page 4 2

3 What is context Context CSE476 Mobile Application Development Yeditepe University Page 5 What is context? (cont.) By example Location, time, identities of nearby users By synonym Situation, environment, circumstance By dictionary [WordNet] the set of facts or circumstances that surround a situation or event Problems: New situations don t fit examples How to use in practice? CSE476 Mobile Application Development Yeditepe University Page 6 3

4 Operational Definition of Context Context is any information that can be used to characterize the situation of an entity. An entity is a person, place, or object that is considered relevant to the interaction between a user and an application, including the user and the application themselves. [Dey and Abowd, 2000] Observations - From point of view of developer CSE476 Mobile Application Development Yeditepe University Page 7 Context Categories Recall Dey s goal: operational definition for use by designers and developers Once you have entities, want to identify frequently useful contexts Primary Categories Answer basic questions like who, what, when, where Index into more detailed secondary categories Secondary Categories More specific details that may be relevant CSE476 Mobile Application Development Yeditepe University Page 8 4

5 Primary Categories Identity: every entity has a unique id Location: position, spatial relationships (latitude/longitude, with friends, near a Starbucks, in the library) Activity: what s happening in the situation (touring a museum, reading a book) Time: current time, duration of event, temporal ordering CSE476 Mobile Application Development Yeditepe University Page 9 Secondary Categories Indexed by primary category Phone number, address, social network, etc.. E.g. identity -> address, phone number, etc.. CSE476 Mobile Application Development Yeditepe University Page 10 5

6 What is Context-aware? The term context aware software was first introduced by Schilit and is categorised as software that adapts according to the location of use, as well as the proximity of entities (people, hosts, and / or devices). Schilit et al, 1994 Schilit describes contextual information as relating to either: Computing context: i.e. information relating to network connectivity, printers, scanners, projectors, workstations (objects that would be found in a computing environment), etc. User context: such as location and orientation, or current social issues, etc. Physical context: such as lighting, noise levels and temperature, etc CSE476 Mobile Application Development Yeditepe University Page 11 A Context-aware application A system is context-aware if it uses context to provide relevant information and/or services to the user, where relevancy depends on the user s task. 1. Presentation of information and services Tour guide, Active Badges 2. Automatic execution of services Smart homes (turn off lights, adjust temperature) 3. Tagging of context to information for later retrieval Digital camera meta-data (time, location) CSE476 Mobile Application Development Yeditepe University Page 12 6

7 Design Principles Context Models Models Key-Value models Markup scheme models Use a hierarchical data structure consisting of markup tags Graphical models Use UML to represent context information Object oriented models Logic based models Ontology based models Attributes Context type Context value Time stamp Source Confidence Simplicity Flexibility Genericity Expressiveness Requirements CSE476 Mobile Application Development Yeditepe University Page 13 Context-aware Computing Definition - Prof. David Kotz (2000) Context-aware computing is a mobile computing paradigm in which applications can discover and take advantage of contextual information (such as user location, time of day, nearby people and devices, and user activity) Mark Weiser s (Xerox Parc) idea of Ubiquitous Computing, creator of Ubicomp Project Active Badge: First Indoors positioning system Implemented (early 1990s) at Olivetti Research Lab in Cambridge, UK Largely influenced by Ubiquitous Computing project CSE476 Mobile Application Development Yeditepe University Page 14 7

8 Context-aware Mobility Components CSE476 Mobile Application Development Yeditepe University Page 15 User Activities CSE476 Mobile Application Development Yeditepe University Page 16 8

9 The Bat Location System Bat Bats Consist of a radio transceiver, controlling logic, and ultrasonic transducer 7.5x3.5x1.5 (cm), 35g 48-bit Globally unique ID Powered by a single 3.6V Lithium cell, a lifetime of around fifteen months Entity location is determined based on the principle of trilateration 3D position can be also deduced Orientation of an object can be deduced CSE476 Mobile Application Development Yeditepe University Page 17 Lancaster University Tour Guide CSE476 Mobile Application Development Yeditepe University Page 18 9

10 Cyberguide Project First Location-aware application in the literature is Cyberguide Project Implemented in 1995 by the College of Computing, Georgia Tech, US CSE476 Mobile Application Development Yeditepe University Page 19 Tourist Guide Simcock et al. Location Based Tourist Guide by Simcock et al. (2003) is also one of the early examples By the School of Computer and Information Science, University of South Australia CSE476 Mobile Application Development Yeditepe University Page 20 10

11 Basic Tour Guide There was life before Google (Maps) All the hot spots had to be located manually App provides: Info on Map, Guided Tour, List Attractions CSE476 Mobile Application Development Yeditepe University Page 21 Usability Failures Having all is just not enough CSE476 Mobile Application Development Yeditepe University Page 22 11

12 How to maintain usability? Usability.gov CSE476 Mobile Application Development Yeditepe University Page 23 Case Study: Evaluation of Context aware Tour Guides This study was conducted at Brunel University, West London, UK in 2003 It evaluates a prototype GPS-enabled and non-gps Campus Tour Guide, and compares the findings. To provide the best audio, video and textual experience, the experiment was conducted using a laptop and GPS receiver + CSE476 Mobile Application Development Yeditepe University Page 24 12

13 Context aware Tour Guide - Requirements Requirement 1 - Display a map of the entire campus (map component). The map will be assigned as the primary point of interaction / change on the user interface. Each polygon behaves as a dynamic proximity location box, causing the system to display information concerning relevant contextual attractions. Requirement 2 Enable the system to connect to a GPS receiver on initiation. The signals will be processed by the application and will produce latitude, longitude and altitude coordinates. This GPS will be updated providing fresh positioning information every second. Requirement 3 Graphically display the users current location on the campus map. Requirement 4 - Display attraction information on points of local interest, based on their position established by the GPS (information component). These attractions will be highlighted on the map and will be based on their current location. CSE476 Mobile Application Development Yeditepe University Page 25 Context aware Tour Guide - Requirements Requirement 5 - Indicate the presence of key attractions on the campus map; allocated by an icon to represent itself on the map. Requirement 6 - Display text-based information and provide images of attractions within the campus. Requirement 7 - Dynamically show pop-up boxes or separate windows containing information about attractions that surround users. CSE476 Mobile Application Development Yeditepe University Page 26 13

14 System Component Non-GPS Tour Guide will have all with the exception of the Positioning Component Hence, the user s location will not be visible on the map in this version. CSE476 Mobile Application Development Yeditepe University Page 27 Tour Guide - Implementation Implemented using MS Visual Studio.net/C# Franson GPS Tools Coordinates collected using Google Maps CSE476 Mobile Application Development Yeditepe University Page 28 14

15 Tour Guide - Implementation CSE476 Mobile Application Development Yeditepe University Page 29 Evaluation Methodology Evaluation conducted using scenarios and questionnaires The questionnaire was to assess against three usability measurements: Effectiveness - measured as the type and level of information assimilated by the user Efficiency - Efficiency was considered as the measurement of time taken by a user to complete a set of tasks. User satisfaction - This parameter was measured by asking each participant to indicate their level of enjoyment whilst using the system on a scale from one to ten CSE476 Mobile Application Development Yeditepe University Page 30 15

16 Evaluation Methodology The experiment was conducted by twelve participants. Six participants used the non-context aware application and six used the context aware system. All twelve participants carried out the experiment with the same controlled conditions using the same route. CSE476 Mobile Application Development Yeditepe University Page 31 Analysis of Data After all experiments were conducted, the participants data was analysed using SPSS. Score, time and satisfaction were classed as dependent variables. In order to analyse these usability measurements, the following analysis questions were addressed for each usability variable: Is this variable dependant on the building, which is being visited? Is this variable dependant on the question number? Is this variable dependant on the participant conducting the experiment? Is this variable dependant on the incorporation of context aware functionality? CSE476 Mobile Application Development Yeditepe University Page 32 16

17 Analysis of Data - Effectiveness ANOVA (ANalysis Of VAriance) test with score as the dependant variable and building number as the independent variable CSE476 Mobile Application Development Yeditepe University Page 33 Analysis of Data - Efficiency ANOVA test with time as the dependant variable and the use of GPS as the independent variable. CSE476 Mobile Application Development Yeditepe University Page 34 17

18 Analysis of Data - Satisfaction To check the impact of context aware system to users general satisfaction, an ANOVA test was done, with satisfaction as the dependant variable and the use of GPS as the independent variable. CSE476 Mobile Application Development Yeditepe University Page 35 18