A population rapidly aging is a global problem. To meet the requirement of assistant living services for elderly person with a reasonable cost, one possible solution is through technology and the Smart Home, which is the main driving vision. Within the research community of Smart Homes, using multi-type sensors to monitor the resident daily activities has attracted more attention. This PhD project aims to build a set of evidential reasoning algorithms to integrate multi-sensor information for recognising human daily activities and to minimise the effect of uncertainty within data generated Smart Homes. In this study. two categories of uncertainty sources have been identified: the uncertainty derived from the envirorunent and the uncertainty from human activities. To deal with these kinds of uncertainty, two types of discounting rates have been suggested to accommodate for the uncertainty: hardware discounting and contextual discounting. To improve the accuracy of the Dempster-Shafer based reasoning method, a revised lattice-based structure was proposed and implemented in conjunction with incorporating the prior knowledge, such as historical activity patterns, into the reasoning process for activity recognition. Two weight factor algorithms, i.e. SWM and CWM, have been proposed to identify optima1 mapping strengths within the revised lattice structure. In this thesis, the relations between different layers, different activities and between sensors and activities were also investigated. To eva1uate the effectiveness of the proposed methods, they have been considered with three public datasets. The empirical results demonstrate that the Dempster-Shafer theory offers an easy way to represent two identified uncertainty information and recognize activity under uncertainty. The SWM algorithm is a better way for detecting the easy and nonnal human activities given that there is sufficient historical data. Otherwise, CWM is a good approach in instances of the lack of historical data and better for reasoning with complex activities.

Mobility is something able-bodied people take for granted. Approximately 132,500 people in the United Kingdom have disabilities which permanently confine them to a wheelchair; 40,000 of these require a powered wheelchair. The opportunity to lead a normal life and be accepted as an equal by the able-bodied population is limited by their reduced mobility. As much freedom of movement as possible is therefore crucial for these people. Powered wheelchair users' mobility depends upon the manoeuvrability of the chair. For optimum manoeuvrability a chair must be capable of moving in any direction. Currently no omni-directional powered wheelchairs are commercially available. This thesis describes the design and deVelopment of a powered base unit for a wheelchair, controlled to instantaneously move in any direction. The novelty is principally represented by the innovative design and configuration of four omni-directional roller wheels* (LUMAN wheels) which, when individually controlled, produce the omni-directional movement of the base unit. Further novelty within the design is a set of bi-directional angled roller couplings that simultaneously disengage the wheels from the motors, via a cable linkage mechanism, and simple control system. Mathematical data models illustrate the theoretical performance of the wheel configuration, and a prototype base unit is tested to prove these hypotheses.