VII Международная студенческая научная конференция Студенческий научный форум - 2015

Nowadays, the field of mobile applications development is growing dramatically to make our lives easier. Thus, special attention is paid to the sphere of context-aware applications development. They are originally designed for the automation of any actions or tasks depending on environmental parameters with minimal intervention from the user. That's why I would like to dedicate this article to this area of software engineering.

I‘ll try to cover all the major issues affecting described area including the urgency of development of this type of mobile application.

Objectives the article are the following:

1. To determine the definition of “context-aware computing and systems”.

2. To formulate the notion of "context".

3. To find out the basic principles of context- aware systems and applications.

4. To identify the key aspects of the context-aware computing theory.

5. To reveal the most perspective lines of research in the field of context-aware computing.

6. To identify what sensors serve as the basic sources of information for context-aware applications.

7. To determine the scopes of the context-aware applications.

8. To prove the urgency of the use of context-aware applications.

The definition of «context-aware computing and applications»? [1a, 4]

Context-aware computing studies the context-aware systems (a combination of hardware and software) that analyze the state of the user and the environment and adapt their work to the changing conditions. They are generally classified as "ubiquitous computing" or “pervasive computing”.

The main sources of information for context-aware systems are location, social and physical environment. In wide understanding, contextual dependence includes people and devices who are nearby the user, internet access, illumination and noise level, as well as interaction with different people in everyday life. For example, whether you are with your family now or with your friend.

In general, “context” is a situation that contains the product we are talking about + changesof this situation. In addition, a context-aware application is a system that change its behavior when the situation changes.

The definition of “context” [3, 4]

In 1994, Bill Sklilit and Marvin Taymor, scientists from Xerox PARC, for the first time used the term "context-awareness" in their report «Disseminating Active Map Information to Mobile Hosts». Taymor and Sklilit define the “context” as location, social environment, objects and changes of these objects.

However, later the trend of context-awareness in software engineering became very popular and now the notion of “context” is very blurred. Nevertheless, there are some conventional definitions of the context, and the most popular among them are definitions of Intel and ISO 9421-11.

The context definition the corporation of Intel:

Context-aware system is a system that can determine the following contexts:

• The context of the environment (physical environment, devices, services)

• The context of the platform (Location, Movement, Network, Battery Status, available abilities of the platform, the current application, level of memory usage)

• The context of the user (Identity, physical the state of, mental state, activity, Contacts, Preferences).

The context definition according to ISO 9421-11:

Context is the users, their aims and objectives, infrastructure (hardware, software and materials), as well as the physical and social environment in which product is used (Figure 1).

Figure 1. ISO 9421-11 definition of context

General principles of building context-aware systems [2, 4]

Context-aware systems have three basic functional characteristics. They can "feel", "think" and "act." Some devices may have sophisticated sensors, but make poor analysis before the action. Others, on the contrary, collect a small amount of information, but perform a thorough analysis.

The first step of the context-aware systems work is collection of data from the various sensors or search for information from alternative sources. Then this information can be used in order to determine suitable variants of operation and to adapt to the conditions. This collected information creates a link between the real physical world and the virtual world of a computer program.

The second step is the analysis of collected data and following storage of the results. After the analyzing, these results can be saved for further use as well as for training the system. The last step is the selection of a suitable version of the behavior of context-sensitive system (Figure 2).

Figure 2. Work of context-aware system

Basic directions of the theory of context-aware computing [1a, 2]

In recent years, The International Conference on Context-Aware Systems and Applications became one of the key events in the sphere of the development of the theoretical basis of context-aware computing. This year's agenda of the conference included the following issues:

1.  

   • Context-aware model

   • Context-aware controls

   • Context-aware algorithms

   • Context-aware networks

   • Context-aware views

   • Systems based on Context-awareness

   • Logic in Context-awareness

   • Reasoning in Context-awareness

   • Formal Methods in Context-awareness

   • Optimization of Context-awareness

This list represents the main lines of development of the theory of context-aware computing.

The most perspective lines of research in the field of context-aware systems [1b, 2]

Also at The International Conference on Context-Aware Systems and Applications the most perspective lines of development in the field of context-aware systems were identified:

• Issues of routing, transport, and reliability of context-aware systems.

• Methods of data dissemination and replication in context-aware systems.

• Applications, mobile social networking applications.

• Mobility models and statistical analysis of the mobile trace.

• The mechanisms and algorithms of Context-awareness.

• The coexistence of opportunistic networks with infrastructure of mobile wireless networks.

• Perception of controlled information processing and decision-making.

• Modeling, performance, scalability, rules and fundamental limits for independent and opportunistic communications.

• Game-theoretic ideas in the operation of autonomic and opportunistic networks.

Sensors as a source of information for context-aware applications [2, 5]

Sensoris a device that measures some physical quantity and converts it into a signal that is available to the observer. Sensors help to identify the elements of the context that are difficult to determine by the computer device by traditional methods

• Proximity Sensor determines that you brought the smartphone to your ear for conversation by the means of infrared beam and gives the command to turn off the screen, so you will not be able to touch some screen button inadvertently during the call.

• Gesture sensor monitors the movement, mainly of eyes or hands, and gives the smartphone pre-programmed commands (for example, scroll through the page in the browser or display the last notification).

• Gyroscope determines smartphone rotation in space along the three axes. Often works in conjunction with accelerometer.

• Accelerometer detects smartphone position in the space along three axes.

• Geomagnetic sensor (compass) uses the Earth's magnetic field for orientation to the cardinal points (widely used in navigation services).

• Barometer. Thanks to this smart sensor, the atmospheric pressure can be measured.

• Hall sensor, as well as the magnetometer, responds to a magnetic field, but, unlike the second one, uses much more simple principle: it does not detect the magnetic field strength on multiple axes, but merely reacts to its gain caused by the approaching of the permanent magnet, hidden in the cover.

• Ambient light sensor automatically adjusts the screen brightness according to the lighting conditions.

• Fingerprint scanner is used in smartphones for user identification by his fingerprints.

Justification of the relevance of the use of context-sensitive computing and applications

Context-aware systems and different kinds of sensors are already available on the market in quite a large numbers. However, this field of software development is gaining more and more popularity among developers of all levels and produsers of the sensors. As evidenced of this fact you can study the list of companies and organizations below (Figure 3) that shows the interest of the majority of the most successful and reputated companies and sientific instututions to this field of software developing.

Figure 3. Companies and sientific instututs

This list is far from complete, but nevertheless it indicates that the leading universities and institutions, as well as the producers, are very interested in the development of this field of software engineering. Thus, it is safe to say that the development of context-aware applications is an extremely relevant area of research and development.

Furthermore, the market of sensors itself also growthes very active (Figure 4). According to Microsoft's, annual turnover of the sensors over the past few years has increased more than three times and in December 2012 it was at the level of $ 9.7 billion.

Figure 4. MEMS-based Sensors and Actuator growth

References

1. 3rd International Conference on Context-Aware Systems and Applications, October 2014:

   1. Emil Vassev & Vangalur Alagar «Context-Aware Systems and Applications» - Springer Science + Business Media New York in 2014.

   2. Phan Cong Vinh & Jun Suzuki «Special Issue on Context-Awareness of Mobile Systems: Models, Algorithms and Applications» - Springer Science + Business Media New York in 2013.

2. http://iccasa.org

3. Matveev, Korneev, Popov "Using contextual information in Windows 8.1 », 2014.

4. https://wikipedia.org

5. Leonids P. «Context-Aware Computing», «Open systems», № 03, 2012

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