Jaringan Bergerak dan Nirkabel(TEP 651)

Introduction to Mobile/Pervasive Computing and Context-Aware

Dr. I Wayan Mustika, ST., M.Eng.

Jurusan Teknik Elektro dan Teknologi Informasi FT UGM

Outline

Mobile/Pervasive Systems Current Computing Trends: From The Virtual to

The Physical Context, Context Awareness, and Situations When Systems Become Context Aware

Mobile/Pervasive Systems

Pervasive = ubiquitous = present everywhere Embedded in your environment WSN, RFIDs, microcontrollers

Mobile = anything that moves A broad class of systems qualify as mobile systems Laptops, cell phones, vehicular networks, wildlife networks

Applications are endless Mobile phone applications, general purpose computing,

smart homes, health care, RFID-based localization, battery less computing

Current Computing Trends: From The Virtual to The Physical

Ubiquitous computing Pervasive computing Invisible computing Proactive computing Autonomic computing Ambient intelligence Sentient computing

Ubiquitous Computing

Refers to the collective use of computers available in the physical environment of users, perhaps embedded in a form invisible to users.

Pervasive Computing

Refers to the vision of devices or computers pervading lives

Pervasive computing can be viewed as a combination of mobile computing (use of computers worn on or carried by users) and computers embedded in the fixed environment and so can be understood as another term for ubiquitous computing.

Invisible Computing

Refers to the use of computers in such a way that the task is focused on and facilitated, without too much focus on the tool (i.e., the computer system) itself

Often, we simply want a task to get done (e.g., get a message to someone), and we might not want to focus on, or wrestle with, the software or the hardware that enables the task.

The overlap with the ubiquitous computing vision is clear; the many computers in the everyday environment that the user might interact with are merely the tools to perform tasks and so should be given only as much attention as a tool deserves.

Proactive Computing

Refers to a focus away from interactivity to computers anticipating user needs and taking action on users behalf.

The idea is that human attention devoted to interaction can be reduced so that users can focus on higher level tasks.

Autonomic Computing

About building systems that can self-monitor, self-heal, and self-configure.

Proactive and autonomic computing overlap, in that they both relate to ubiquitous computing systems and could utilize context information about the environment of the system and users to operate or make decisions.

However, they differ in their emphasis on the kind of system behavior to be achieved.

Ambient Intelligence

Builds on ubiquitous computing and intelligent user interfaces to obtain greater user friendliness and efficient services for users.

In this vision, people will be surrounded by intelligent and intuitive interfaces embedded in everyday objects around us and an environment recognizing and responding to the presence

Certainly, context-aware computing overlaps with the ambient intelligence vision

Sentient Computing

Refers to systems using sensors and resource status data to maintain a model of the world which is shared between users and applications.

Because such systems try to build a model of a part of the world from sensory information about the users circumstances and environment, the idea is very much suggestive of, if not synonymous with, context-aware computing but with an emphasis on the world model.

Context, Context Awareness, and Situations

What is context? The Free Online Dictionary of Computing: that which surrounds, and

gives meaning to, something else. This definition can be specialized to the application at hand. Whether

that something is an assertion in a logic, a person, an utterance, or a computer system, with a suitable definition for meaning, the intuition captured by the word context serves its purpose.

Schilit et al. (1994): from the perspective of distributed and mobile computing, where a person is that something, and context refers to information about a persons proximate environment, such as location and identities of nearby people and objects.

Dey (2001): very useful in practice and suitable for pervasive computing: 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 applications themselves.

Pervasive computing utilizes contextual information about the physical world.

This implies a number of important concerns related to the connection of sensor information to context-aware pervasive computing, including 1) what can be feasibly sensed, 2) the best way to acquire sensor information, 3) how to reason with sensor information to infer context.

In fact, any information which can be practically obtained via sensors can be used as context, including the emotional states of users and movements.

Making such artifacts aware enables automatic behaviors without users direct intervention and can enhance the function of the artifact or add aesthetic value, both of which can differentiate an artifact from others in the marketplace.

Closely related to the notion of context is the notion of situation. The relationship between context and situation is illustrated in Deys operational definition cited earlier.

A definition of situation from the American Heritage Dictionary is as follows: The combination of circumstances at a given moment; a state of affairs.

So, the idea is to aggregate (perhaps varieties of) context information to determine the situation of the entities (relevant to an application). In this sense, we can view situation as being at a higher level of abstraction than context.

The notion of situation can be useful in pervasive computing in that the situation abstraction allows the modeler or application designer to effectively carve the world up into manageable pieces, which can then be recognized by the system via its sensors.

When Systems Become Context Aware

Context-aware software adapts according to the location of use, the collection of nearby people and objects, the accessible devices, as well as changes to those objects over time. A system with these capabilities surveys the computing environment and reacts to changes to that environment.

Context-aware pervasive computing is a study of pervasive computer systems (a combination of hardware and software) that are aware of context and can automatically adapt and respond to such context. Context awareness enables the system to take action automatically, reducing the burden of excessive user involvement and providing proactive intelligent assistance.

Such context-aware pervasive systems have wide-ranging applications, including context-aware information retrieval, reminder systems, context-aware mobile services and electronic tour guides, sentient objects, sentient cars, sentient buildings, context-aware response to emergencies, and intelligent context-aware environments, with potential benefits to society, ranging from proactive automated healthcare and effective E-commerce to more effective military systems and safer cars. Indeed, one can also utilize context awareness in security warning systems in the home or public spaces. Many future computing systems will advantageously be context aware, and context-aware systems are becoming increasingly important, receiving worldwide attention from academia and industry.