Pervasive Computing

Pervasive computing is a trend towards information being readily available to anyone, anywhere at anytime. This trend is due to the decrease in powerful microprocessors being embedded in everyday objects enabling users and devices to connect wirelessly to the internet, devices, and to other users from wherever they may happen to be. Pervasive computing thus provides users with the ability to access and take action on information conveniently. This idea of pervasive computing is to enable users to interact other users and access information in a more natural form such as merely speaking and gesturing. Mobile phones and personal digital assistants (PDAs) have become very much a part of everyday life due to the many functions they provide and the functions that are yet to be implemented. These functions are made possible through chips being made smaller and able to compact different functionalities. Pervasive computing will usher in new forms of collaboration, communication, the ease of acquiring information, and performing functions that will become the norm in homes, clothing, and businesses. What pervasive computing does is eliminates the steps to complete tasks. For example if a student needed to go to a library to do research for a term paper he/she would get dressed, drive, walk, or take public transportation to reach the library, and ask a librarian to direct him/her to the resources. Today all it takes is having an internet connection and the library comes to the student. Eliminating steps to achieve a goal, whatever the goal maybe, reduces time and money. The valuable time someone saves in completing a task, creates more time to pursue others. Smart home is one of the many examples of pervasive computing where devices communicate with other devices in the home. “Over the last 15 years, computerized controls have become more and more common in our homes.” Although the smart home differs from other homes, the main difference is that in a regular home each device is separate and functions independent of other devices. In a smart home a communications infrastructure is installed that allows various systems and devices in the home to communicate with each other therefore allowing the passing of information and commands through this connection. When designing a smart home, every effort should be made to ensure that it works in the same or a similar manner to other houses. “Therefore, pushing a door should still open it and clicking a light switch should still turn the light on or off. However, the house can also be operated in a variety of other ways that may be more useful or appropriate for the person living there.” An advantage of the smart home technology is that equipment that already exists in the home can be adjusted to provide more functions. For example, “detectors normally used for security alarms can be used to identify if someone is in a room or if the room temperature has changed.” In addition, equipment can be implemented to open and close doors and windows automatically. For the most part, the smart home is computerized and built on existing bus wiring in the house. “The computers control our washing machines, microwaves, heating, and provide new ways to monitor the safety and security of the homes.” The goal is to create and expand the use of existing computers into other parts of the home through a single network that can be easily controlled. Through computers it would be possible to eliminate the step of flicking a switch manually versus controlling the lights remotely. These computers are linked together using either a dedicated cable or by sending a special signal through the main electricity cables. The security alarm panel in the house also operates as an answering machine and can be used to dial into the house and tell it to do certain things. This system relies on a PIN number, similar to the one used at a cash point to ensure that only authorized users can control the house in this way. The system has a series of voice prompts that will guide the user through the operation of the house. For example, if you are late coming home one evening you can call the house and command it to close the curtains when it gets dark. Also, if you have been away from the house for a few days and want to be sure the house is warm on your return; you can call the house and switch the central heating on. This system can also be used to call you at work or on a mobile phone if someone rings your doorbell when you are not in the house. Some of the main features of a smart home include, but are not limited to:

• Integrated Security • Safety Systems • Independent Living • Telephone Control • Dedicated Wiring Bus • Power Line Communication • Infrared Communication • Radio Frequency Communication

Another aim of the smart home is to eliminate the need for mechanical switches and allowing computerized systems to make decisions. In the smart home the switch takes on a different function. Rather than regulating the flow of electricity, the switch sends a signal to a communication network (bus system), informing the network of the new position of the switch. The regulation of electrical flow takes place at the controller rather than at the switch unit. If the bus system connects more than just lights, it is possible to radically change the way the home is controlled. Since the switch is no longer directly related to any particular device, it can operate any device on the network that has been commanded to respond to the signal from the switch. Devices in the home are now able to change status in response to a signal on a network and so commands no longer need to come from a physical switch. While many smart homes rely on distributed control systems that do not need a personal computer to operate, computers can be used as an interface with the home. These computers can be used to send messages to, and receive messages from the smart home. According to Duncan Graham, the use of a web server in the home would allow a visual representation of the home to be created as a web page and accessed from a web browser. This could be used to control the home either from inside over a local area network (LAN) or remotely if an internet connection is always on in the home. In Barcelona, a company called Eneo Labs specializes in providing services for a “Connected Home” as they call it. One of the services they provide is having the ability to monitor your home through you phone real time. Another would be to send alerts by SMS if anything in the home malfunctioned. General Manager Javier Zamora explains how smart houses consist of two components. An “information network” (Figure 1), which can be considered as the nervous system in the human body, connects all devices in the home making it possible to communicate; and a brain (Figure 2) co-ordinates the environments inside the home to connect to what goes on outside. The Connected Home became possible to ADSL (figure 1) lines rolled out into homes which set up the information network.
[pic]Figure 1

[pic]Figure 2

“It would also be security-conscious and aware of its occupants’ well being, monitoring whether some one has fallen, and control temperature and light settings, depending on what is happening outside.” CNN.

The use of the wireless application protocol (WAP) allows mobile telephones to link to a limited version of the internet. Setting up the home with a (WAP) server will allow for control through a mobile phone or other remote device. Recent developments in speech recognition technologies are making it possible for spoken commands to operate the home. In the past microphones would have to be positioned close to the user's mouth in order to eliminate background interference, but more centrally located microphones now solve these problems and enhance the technology. Each room in the home can have a temperature sensor that maintains the room at the temperature set on the main controller. The central heating can also be turned on and off from any remote control device. Externally, there can be a detector that measures wind speed and light level. Internally, each room can be equipped with a multi-function detector head that looks similar to a smoke detector. The detector can measure smoke, temperature (for fire and heating), light level, movement (using passive infrared), and carbon monoxide. This detector also has an infrared receiver, emergency light, siren, and microphone. These detectors are used to allow the house to respond to changing conditions and to remote control devices. The security system panel can be used to act as the answering machine for the smart house. Setting the alarm will activate the central locking system, and this will close all windows and doors and can also switch off any devices needed. For example, you may want it to turn off any lights left on during the daytime or turn off the electrical devices in case of a power outage or fire. The security system can also be operated through the internal telephone or by dialing into the house from an outside line. If necessary, special replacement plugs can be fitted into the home that will allow remote control of the appliances. The adaptors can be turned on or off from buttons on the plug, or through any of the remote control devices.

The designers of a smart home need to take into account not only the form of the house itself but also the requirements (both generic and specific). The Joseph Rowntree Foundation (JRF) has used Echelon's Lon Works communication protocol in the development of its smart homes, but this is only one of the potential ways of achieving interoperability. The underlying technologies used will determine some of the subsequent specification decisions. The design and structure of the building in which they will be installed will influence the technologies decided on. The choice of the most appropriate transmission media will depend on the house in which they will be installed. In a new build or major refurbishment project, a dedicated wiring bus system may prove more appropriate. An appropriate understanding of the user and their needs will form an essential part of any specification. Motorized devices tend to be an expensive element of any installation and so the costs / benefits of their usage must be carefully considered. The distributed nature of most smart homes systems means that the failure of a single device is unlikely to disrupt the whole system. The use of battery back-up systems that are often incorporated in low voltage devices should also be considered in case of power failure.

In September 2005, a host of new wireless gadgets designed to help make buildings and homes "smart" debuted at the ZigBee Open House and Exposition in Chicago. Among the gadgets was a domestic awareness system that warns you if the stove is left on or if the basement starts flooding. Another system at the exposition allows you to network your home entertainment system with environmental controls such as light dimmers or a thermostat. Underlying the systems is a new wireless-networking standard called ZigBee that was developed by the ZigBee Alliance. Many earlier smart systems used proprietary technology; ZigBee is built on an Institute of Electrical and Electronics Engineers (IEEE) global standard (802.15.4). This is similar to the standards that govern Bluetooth and Wi-Fi. Technology however, unlike Bluetooth and Wi-Fi networks which require central hubs that distribute information to dispersed devices, ZigBee allows devices to form mesh networks. Mesh networks are far more robust than their hub and spoke counterparts as each unit can relay information to its neighbors. If a node breaks down, other nodes can automatically reroute transmissions around it. This is an advantage in something like a building-wide lighting system because you would not want one bad switch to bring the whole thing down. Mesh networking could let ZigBee systems link as many as 64,000 devices. In contrast, Bluetooth networks are limited to just eight nodes.