IJCET - Systematic Review of Ubiquitous Computing System Models

International Journal of Computer Engineering and Technology (IJCET), ISSN 0976-6367(Print),
INTERNATIONAL JOURNAL OF COMPUTER ENGINEERING &
ISSN 0976 - 6375(Online), Volume 5, Issue 2, February (2014), pp. 46-55 © IAEME

TECHNOLOGY (IJCET)

IJCET

ISSN 0976 – 6367(Print)
ISSN 0976 – 6375(Online)
Volume 5, Issue 2, February (2014), pp. 46-55
© IAEME: www.iaeme.com/ijcet.asp
Journal Impact Factor (2014): 4.4012 (Calculated by GISI)
www.jifactor.com

©IAEME

SYSTEMATIC REVIEW OF UBIQUITOUS COMPUTING SYSTEM MODELS
SmritiMahajan1,
1,2,3

Anil Kumar Mishra2

and

Latika Singh3

Dept of Computer Science and Engineering, ITM University Gurgaon, India

ABSTRACT
Ubiquitous computing forces computers to live in the world of humans. We can that
ubiquitous computing is roughly the opposite of virtual reality. With advancement in technology we
will soon see large number of ubiquitous devices. The services delivered by ubiquitous computing
environment will require evolution of context-awareness, wireless network and mobility. Almost all
applications of ubiquitous computing require a middleware for its implementation and a mechanism
for discovery of available services. In this paper we will study about SenSay, the context-aware
application of ubiquitous computing; the middleware architecture HOMEROS which allows high
flexibility in the environment of heterogeneous devices and users; dynamic discovery and invocation
mechanism for discovery of available services; Mobile Gaia a middleware for ad-hoc pervasive
computing.
Keywords: Dynamic discovery and invocation, HOMEROS, Mobile Gaia, Pervasive computing,
SenSay, Ubiquitous computing.
1. INTRODUCTION
The term Ubiquitous Computing was coined by Mark Weiser in 1991. His vision was to
create environment saturated with computing and communicating capability, and integrated with
human users [1]. This vision was too far ahead of its time and the hardware technology that was
needed to achieve this did not exist. Ubiquitous computing is an advanced computing concept where
computing is made to appear everywhere and anywhere [2]. In terms of technology, the term
ubiquitous implies that technology is everywhere and we use it all the time. These technologies have
been integrated in our lives so well that we tend to use them without thinking about the tool.
Ubiquitous computing is also known as Pervasive Computing [3]. Both these terms can be used for
the technology that has become almost invisible to us as it is now an integrated part of our life. It is
an emerging field that includes technology that bridge the physical and digital world; systems and
46


applications that incorporate such technologies; infrastructure that support these technologies. It is
the prospect of connecting all the things in the world to internet in order to provide information on
anything, anytime and anywhere. It relies on the convergence of wireless technology, advancement
in electronics and the internet. Continuous advancement in technology will soon lead to abundance
of very small and very cheap microprocessors which are equipped with sensors and have wireless
communication capabilities. Processing of information will then become ubiquitous and permeate
almost every type of object. In ubiquitous computing environment, the design of systems and
applications needs to take care of different devices, mobile users and continuously changing contexts
of both the users and the system. The agents can acquire contextual information easily using
middleware, reason about it using different logics and then adapt themselves to changing contexts. In
this paper we will study about:
•
•
•

A context-aware mobile phone SenSay.
Two middleware architectures-HOMEROS and Mobile Gaia.
Dynamic discovery and invocation mechanism.

The rest of the paper has following structure: section 2 presents an application of Ubiquitous
computing-SenSay; section 3 describes HOMEROS-the middleware used for mobile heterogeneous
systems; section 4 elaborates the mechanism for dynamic discovery and invocation of service
components and section 5describes Mobile Gaia-a middleware for Ad-hoc pervasive computing.
2. SENSAY: A CONTEXT-AWARE MOBILE PHONE
SenSay(sensing & saying) is a context aware mobile phone that adapts to the dynamically
changing environment[4]. It modifies its behavior based on its user’s state and surroundings. It gives
the ability to communicate the urgency of their calls to the remote callers, suggests user to make calls
when they are idle and gives the feedback on the current status of the SenSay user to the caller.
SenSay introduces 4 states: uninterruptible, idle, active and the default state the normal state
(fig 1). The architecture consists of 5 functional modules: Sensor box, sensor module, decision
module (core), action module and phone module.
2.1 Sensor Box
It consists of a printed circuit board (PCB) which consists of two subsystems: the sensors and
the microcontroller. The microcontroller provides eight 10-bit analog-to-digital conversion channels
as the interface to the sensors and a port for serial communication to interface with the sensor
module.
The various sensors integrated in the sensor box are the voice and the ambient microphones
which can be mounted on various parts of the body; three accelerometers to capture three(x, y, z)
degrees of motion which are mounted directly on the PCB; and the light sensor mounted on the
phone. Each sensor in the sensor box has a unique ID.
The sensor box polls its sensors periodically as quick as it can and stores the most current
value in an array.
2.2 Sensor Module
The sensor module queries the sensor box (once per second) and returns the data to the
decision module. Standard RS232 serial connection issued to establish the connection between the
microcontroller and the sensor module.
At any time, the sensor module will query the sensor box for a particular sensor data using
the unique ID of that sensor. When a query is processed, the microprocessor will respond with the
47


most recent reading of the sensor by doing a table lookup rather than actually polling the sensor. This
allows the microcontroller to respond immediately.
2.3 Decision Module
The decision logic provides the logic used in state management. The sensor module transfers
the sensor data to the decision module. It queries the sensor data and the electronic calendar of the
user to determine the state of the user and issues phone actions.
Sensor value history (of up to 10 minutes) is stored to help determine the user’s state so that
the transitions can be done smoothly.
2.4 Action Module
This module is controlled by the decision module and is responsible for issuing changes in
setting and operation on the phone. The basic operations supported by the module are:
1. Ringer control: off/low/medium/high
2. Vibrate control: on/off
3. Send an SMS to the caller
4. Make call suggestions
5. Provide access to the electronic calendar.
2.5 Problem
With distributed systems and mobile computing, privacy is a major concern and it becomes
complicated by pervasive computing [5]. With context aware devices, the information about user’s
movements, behavior patterns and habits becomes more knowledgeable with mechanisms like
location tracking, smart spaces and use of surrogates. The knowledge of this information is necessary
for successful proactivity and self-tuning but, the use of this information should be strictly
controlled. If not, it can be put to a variety of unsavory uses ranging from targeted spam to
blackmail. This may prevent knowledgeable users from using a pervasive computing system.
To be reliable on infrastructure, the user must trust the infrastructure to a considerable extend.
Also the infrastructure should be confident of the user’s identity and authorization level before
responding to the request.
3. HOMEROS
To support the computational needs of mobile users we need to maximize the use of available
resources and minimize user distraction which is caused by dynamic and frequent changes in the
resources. The middleware architecture HOMEROS satisfies these needs [6]. It allows high
flexibility in the environment of heterogeneous devices and users. It consists of three layers- the core
component management layer, the extended component service layer, and the system support layer.
This architecture was designed to provide maximum flexibility in supporting service providers and
user requirements.

48


Figure 1: SenSay architecture depicting 5 modules
3.1 Core Component Management
This module consists of core ORB components and interrelated set of basic services which
allows collaboration of service component development vendors. It allows dynamic loading,
unloading, transferring, creating, and destroying the components in the upper layers.
HOMEROS offers seven basic services: Event Manager, Component Repository, QoSAdaptation, Configuration Manager, Resource Manager, and Security manager. All of the services
could be built on top of existing middleware services to support HOMEROS service architecture.
3.2 Event Manager
The event manager distributes events and implements a decoupled communication model
based on suppliers and consumers for enhanced reliability and stability. It has a single entry point
and one or more event factories. Applications can define and register their own factories for state
changes. If a supplier fails, the service can automatically replace all the corresponding information
entries from the factory and scheduling queue without disrupting the system. The current event
manager implementation uses CORBA’s event service.
3.3 Component Repository
The component repository stores information (name, type, services, and so on) about all the
components available in the middleware and allows applications and component manager browse
and retrieve entities on the basis of specific attributes. The current component repository uses
standard SQL for query component entities.

49


3.4 Context Manager
Mobile agent collects overall user information and hardware, software information for
resource management, and the context manager provides proactive services using that information. It
prepares personal data, user preferences, device characteristics, and organized data automatically
available to other components.
3.5QoS Adaptation
This module supports resource manager and configuration manager. It collects various
devices monitoring information from resource manager, and then provides QoS information to the
configuration manager.
3.6 Configuration Manager
The configuration manager configures the new components and improves the component
performance by optimizing system resource usages. It supports mobile agent for collecting
environment information and running specific processes.
3.7 Resource Manager
Resource manager allows dynamic reallocation of resources based on resource awareness.
The middleware platform allows the system to be aware of the available configuration resources. It
performs both self-inspection and self-adaption.
3.8Security Manager
HOMEROS proposes platform registration and authentication, and stability evaluation of
authentication. Registration can be done without user’s intervention, and platform authentication is to
certify that relevant platform is reliable. Registered agents take part in the authentication process for
other unregistered agents and platform.
4. DYNAMIC DISCOVERY AND INVOCATION MECHANISM
Ubiquitous computing environment involves a variety of devices of different capabilities. The
middleware takes a crucial role for efficiently coordinating the components and providing proper
services. In the previous section we have read about a middleware architecture called HOMEROS.

Figure 2: The HOMEROS Architecture
50


All the service providing components in an environment registers them with the system,
providing information about the services they provide [7]. Service proxy agent represents the service
of the components in the world of agents. All the services that provide the same functionality are
wrapped by a service proxy. The service proxy is also registered with the system. Fig3 illustrates the
mechanism for dynamic discovery and invocation of services.
All the providers of a specific service and the proxy of that service register to the system
(step A and step B). The smart room agent (SRA) which acts as a gateway for all the services
receives the service invocation request from the client (step 1). The SRA then searches the registry
for a proxy for such a service (step 2) and forwards the request to it (step 3). The service proxy on
receiving a request checks the registry for available service providers (step 4). The proxy then
activates a selection algorithm to decide to which provider to forward the request (step 5).

Figure 3: Dynamic discovery and invocation mechanism

5. MOBILE GAIA
Mobile Gaia [8] [9] [10] is the middleware for ad-hoc pervasive computing. It is a service
based middleware that integrates resources of various devices. Ad-hoc pervasive computing is a
cluster of personal devices that can communicate and share resources among each other. The user
51


can program the cluster through a common interface. This cluster is also referred as a personal active
space. Mobile Gaia contains services which help in discovery of devices that form the personal
space, maintaining the composition of the cluster, sharing resources among devices in the cluster and
facilitate communication. It provides an application framework for development of applications for
the device collection. This decomposes the application into smaller components that can run on
different devices in this collection. The services are present in two roles-coordinator and client.
The core services make up the kernel of Mobile Gaia and enable the devices in the cluster to
share resources and data seamlessly. The component management core provides necessary low level
support for creating and managing components.
5.1 Service Deployment Framework
Services in Mobile Gaia are implemented as components and this framework forms a
container for these service components. It installs new service components, load and unload
components and remove components when they are no longer needed. It is based on the “What You
Need Is What You Get” (WYNIWYG) model. When a service is deployed, it specifies the
components that are to be loaded in the coordinator and client roles. Whenever a device changes
roles from coordinator to client or vice versa, the cluster management service notifies the service
deployment framework of this change.
5.2 Discovery and Cluster Management Service
Mobile Gaia has the ability to dynamically discover nearby personal devices and bootstrap a
personal active space on the discovered devices. Discovery protocols like Bluetooth or IrDA are
used. When new personal devices are within range, they are added to the personal active space on the
fly.
Depending on the capabilities of the new device, the framework loads appropriate
components and runs additional services that allow the system to utilize the device’s capabilities.
Once a device is out of range, it is automatically removed from the personal active space. It also
maintains a database of active devices and services in the personal active space and a list of
components running locally on the device.
5.3 Event Service
The event service is used to send events among devices in the cluster. These events include
updates to location information; heartbeat messages events, it informing that the device is part of the
cluster and location-based events. Events are implemented using event channels. When an
application wants to send creates an event channel in the host device. The event service of the host
device registers the event channel with the coordinator. The event service in the coordinator
maintains a list of event channels in the cluster. When an application wants to subscribe to an event
channel, it queries the local event service which in turn queries the event service of the coordinator
for event channels. The event service of the coordinator acts like a repository that contains
information about various event channels in the cluster.
5.4 Location Service
The location service enables location awareness in the device cluster. Different devices in the
cluster have different location-sensing technologies such as GPS, WiFi, RFID, Ubisense etc. It fuses
location information from different devices and arrives at a probabilistic estimate of the location
information. This location information is conveyed to all devices in the cluster. This cooperative
approach to sharing location information enables devices to be location-aware in heterogeneous
location-sensing environments. It supports a spatial database that contains a spatial model of the
52


physical world. Spatial information is required for route planning, finding points-of interest and for
location-based triggers.
5.5 Security Service
Security which is essential in personal active spaces can be divided into two main parts –
authentication and access control. Authentication is needed to ensure that only authorized devices are
allowed to connect to a user’s personal active space, and a device can only connect to personal
spaces approved by its owner. Access control identifies what information or resources a device can
share with a specific space name. Authentication is done using public key. For access control, users
are allowed to create simple security policies on the personal device, which specify what services
may run on the device when connected to a certain space.
6. DISCUSSION
In this paper we have discussed about an application of ubiquitous computing, middleware
architecture and the mechanism for dynamic discovery and invocation. The application SenSay
combines sensory data, user information and history information to create a context-aware phone.
The smart features provided by the phone aim to improve the overall usability of the phone. It either
notifies the user of an incoming call by adjusting ringer and vibration settings or eliminates
unwanted interruptions. The middleware HOMEROS provides high flexibility by adopting a hybrid
network model and dynamically configurable reflective ORB. All major ubiquitous computing
projects have established sophisticated middleware architectures. These architectures however face
challenges of integrating large number of perceptual components. These challenges require
establishment of intelligent methods for discovering, invoking and managing distributed
components. Dynamic Discovery and invocation mechanism registers all the service proxies and
their related services available in a smart space. It then provides services to the clients on request.
The middleware Mobile Gaia is a service based middleware which provides dynamic discovery of
near by devices. The services in this architecture are decomposed in two roles- coordinator and
client.
It also supports an application framework that can decompose an application into
components. A device can act either as a coordinator or as a client. Table 1 summarizes the various
system models studied in the paper.
7. CONCLUSION AND FUTURE SCOPE
Ubiquitous computing is an emerging field. Two decades ago, when the term was
coined, Mark Weiser’s vision of ubiquitous environments was too far ahead of its time. The
hardware technology that was needed to achieve this did not exist. But with continuous advancement
in the field of wireless technology, microelectronics and World Wide Web, creating ubiquitous
environments became possible. We can presently see some efforts involved in the construction of
ubiquitous applications in domain areas such as ambient intelligence, pervasive healthcare,
ubiquitous learning and urban spaces. The future projects in this field are smart homes [11] and
ubiquitous city [12].

53


Table 1: SUMMARY TABLE
Functionality
SenSay

HOMEROS

Discovery and
Invocation
Mechanism

Mobile Gaia

Components

It is a context-aware
mobile phone that
adapts dynamically to
the user’s environment
and
modifies
its
behavior.
It is a middleware
which is designed to
maximize the use of
available resources and
minimize
user
distraction caused by
dynamic and frequent
changes
in
the
resources for mobile
users.
It is used to discover
the devices in a smart
space and register them
with the system which
provides information
about their services.
It is the middleware for
ad-hoc
pervasive
computing
that
integrates the resources
of various devices.

Security

Sensor Box, Sensor
Module, Decision
Module,
Action
Module and Phone
Module.

If not controlled,
information about
user’s movements
and behavior can
be put to a variety
of unsavory uses.
Three LayersIt provides security
Core Component through platform
Layer,
Extended registration
and
Component Service authentication.
Layer,
System
Support Layer.

Service providing
components,
Service
proxy
agents
and
Knowledge
base
server.
Service
Development
Framework,
Discovery
and
Cluster
Management,
Event,
Location,
Context
and
Security Service.

--

Future Scope
Mechanisms that
provide complete
security to users’
information
should be
deployed.
The
proposed
architecture needs
to be compared
with
other
middleware
architectures
proposed
for
PDAs and mobile
devices.

--

Security
is Future work will
provided
by be
address
authentication and challenges posed
access control.
by mobility of
nodes
at
application/servic
e layer.

REFERENCES
[1]
[2]
[3]
[4]
[5]
[6]

Weiser, M. (1991).The computer for the 21st Century.In Scientific American, vol. 265, no. 3,
1991, pp. 66-75.
Mattern, F. ,”The Vision and Technical Foundations of Ubiquitous Computing”, UPGRADE
Vol II, No 5, 2001.
Ferscha, A. , “What is Pervasive Computing?”.
Siewiorek, D.;Smailagic, A. ; Furukawa, J. ; Moraveji, N. ; Reiger, K. , “SenSay: A contextaware mobile phone”,Seventh IEEE International Symposium on (2003), pp. 248-249,.
Satyanarayanan, M.,”Pervasive computing: vision and challenges”, IEEE Personal
Communications, 2001.
Han, W. ; Bong, Y. ; Yoon ; Youn, H. ; Cho, W ,”A new middleware architecture for
ubiquitous computing environment”, Proceedings of the Second IEEE Workshop on Software
Technologies for Future Embedded and Ubiquitous Systems, 2004 IEEE.

54


[7]

[8]
[9]

[10]
[11]

[12]
[13]

[14]

Pandis, I. ; Soldatos, J. ; Paar, A. ; Reuter, J. ; Carras, M. ; Polymenakos, L.; ”An Ontologybased framework for dynamic resource management in ubiquitous computing environment”,
Proceddings of the second International Conference on Embedded Software and Systems,
2005 IEEE.
Chetan, S. ;Muhtadi, J. ; Campbell, R., “Mobile gaia: A middleware for ad-hoc pervasive
computing”, 2004 IEEE.
Roman, M.; Hess, C.; Cerqueira, R.; Campbell, R.; Narhstedt, K., "Gaia: A middleware
infrastructure to enable active spaces" IEEE Pervasive Computing Magazine, vol. 1,
pp. 74-83, 2002.
Chetan, S.;Muhtadi, J. ; Campbell, R.,”A middleware for enabling personal ubiquitous
spaces”.
Alam, M.;Reaz, M. ; Ali, M.,“A review of smart homes- past, present and future” IEEE
Transactions on System, Man and Cybernetics-Part C: Applications and Reviews, Vol 42,
No. 6, November 2012.
Shin, D.,”A realization of pervasive computing: ubiquitous City”2010 IEEE.
S.Mohan Raj, “Feasibility Study of Pervasive Computing Approach for Energy Management
in Mobiles”, International Journal of Computer Engineering & Technology (IJCET),
Volume 3, Issue 3, 2012, pp. 312 - 319, ISSN Print: 0976 – 6367, ISSN Online: 0976 – 6375.
Aakash Shah, Gautami Nadkarni, Namita Rane and Divya Vijan, “Ubiqutous Computing
Enabled in Daily Life”, International Journal of Computer Engineering & Technology
(IJCET), Volume 4, Issue 5, 2013, pp. 217 - 223, ISSN Print: 0976 – 6367, ISSN Online:
0976 – 6375.

55

IJCET - Systematic Review of Ubiquitous Computing System Models

Recommended

Recommended

More Related Content

What's hot

What's hot (19)

Viewers also liked

Viewers also liked (20)

Similar to IJCET - Systematic Review of Ubiquitous Computing System Models

Similar to IJCET - Systematic Review of Ubiquitous Computing System Models (20)

More from IAEME Publication

More from IAEME Publication (20)

Recently uploaded

Recently uploaded (20)

IJCET - Systematic Review of Ubiquitous Computing System Models