| For the hierarchical transmission of digital video employing an OFDM scheme diierential and coherent modulation are compared. Special emphasis is given to limitations due to implementation aspects. We investigated a scheme adopted to a data rate ratio of 1:1 between high priority and low priority video data. For a non{moving receiver and diierential reception we obtained a loss of 2.5 dB (in ...

Real-time signal processing applications can be described naturally with dataflow graphs. The systems we consider have a mix of real-time and non-real-time processing, where independent dataflow graphs represent tasks and individual dataflow actors are subtasks. Rate-monotonic scheduling is optimal for fixed-priority, preemptive scheduling of periodic tasks. Priority inheritance protocols exten...

In many cognitive radio applications, there are multiple types of message queues. Existing queueing analysis works in underlay CR networks failed to discuss packets heterogeneity. Therefore high priority packets with impatient waiting time that have preemptive transmission opportunities over low class are investigated. We model the system behavior as a M/M/1+GI queue which is represented by a t...

In real-time (RT) computing systems, a service function execution including an output action is typically subject to a deadline. Scheduling algorithms play a significant role in the design of such systems. They are the major factor in determining the execution safety, i.e., the possibility of always executing control service functions without missing deadlines in a given execution engine posses...

BACKGROUND We assessed change between 1996 and 2006 in the opinions of the general public on priorities for the prevention of health problems. METHODS Postal questionnaire surveys in 1996 and 2006, in representative samples of the general population of Geneva, Switzerland. Participants indicated, for each of 13 health problems, a priority rating for the spending of prevention resources. RES...

In this paper, an energy-efficient scheduling algorithm, called ceiling-based conditional abortable scheduling (CB-CAS) algorithm, is proposed to schedule periodic hard real-time tasks in a non-ideal DVS processor. Based on the schedulability analysis, CBCAS calculates a proper processor speed for task execution so that the energy consumption can be reduced without violating the timing constrai...