Aware Adaptive Systems Research Articles

Dynamic rule generation and rule matching for composite environmental condition in context aware system

Context aware adaptive system need to have some model for their adaptive behavior. These models need to have effective adaptive mechanism to react to the changes in the environment. Specifying the adaptive behavior and ensuring the correctness of the adaptive behavior is the challenging task. Correctness of the adaptive behavior can be assured by designing the complete and consistent adaptive rules. While designing the adaptive rule, sometimes there may be situation where some environmental changes are not addressed. In this proposed work we generated the adaptive rules for all combinations of context values in the defined adaptive rules. We have discussed the priority based rule matching process for finding the decision classes for the newly generated rule. We have used Attribute effectiveness, Attribute Autonomy and Minimum value dependency criteria of RBDT-1 method for assigning priority to the attribute. This proposed method creates the new adaptation rules from the existing rule set for the undefined context situation which is influenced more than one context variable.

Subjective evaluation of critical success factors for a QoE aware adaptive system

For many years video content delivery has established itself as the killer application. Improving QoE on adaptive streaming is focusing many efforts in the quest for optimized methods and metrics to allow a QoE driven adaptation. Questions such as whether adaptive systems based on Scalable Video Coding improve subjective quality and in which situations or to what degree are still open issues. Tolerance and indifference thresholds for each type of content, conditions or viewer category, with regard to adaptive systems are critical success factors that are yet unresolved. We compare the performance of a complete adaptive system with the traditional, i.e. non-adaptive, approach in subjective terms. Results of surveying 75 participants show that the adaptation improves QoE under most of the evaluated conditions. Tolerance thresholds for triggering adaptation events have been identified. Users accustomed to Internet video are more critical than users that only watch TV. The under 35year old subset among the available population is generally more satisfied with the adaptive system than the older subset.

Position-aided mobile communications

Capacity limits of position aware adaptive mobile communication systems exploiting channel state information (CSI) at the transmitter (CSIT) are presented. The position aware adaptive communication systems are benchmarked against state-of-the-art adaptive modulation and coding (AMC) systems that use only feedback CSI or additionally predict CSIT. Numerical results show that position aware adaptive systems achieve large capacity gains compared to state-of-the-art AMC systems for medium to large feedback delays.