Control Aware Radio Resource Allocation in Low Latency Wireless Control Systems

© 2014 IEEE. We consider the problem of allocating radio resources over wireless communication links to control a series of independent wireless control systems. Low-latency transmissions are necessary in enabling time-sensitive control systems with high sampling rates to operate over wireless links. Enabling low-latency through fast data rates comes at the cost of reliability in the form of higher packet error rates due to channel noise. However, the impact of such communication link errors on the control system performance depends dynamically on the control system state. We propose a novel control-aware communication design to the low-latency resource allocation problem. In our proposed method, we incorporate both control and channel state information in scheduling transmissions across time slots, frequency bands, and data rates using the next-generation Wi-Fi scheduling architecture. Control systems that are closer to instability or further from a desired range in a given control cycle are given higher packet delivery rate targets to meet. Rather than a simple priority ranking, we derive precise adaptive packet error rate targets for each system needed to satisfy control-specific performance requirements. We use these adaptive rate targets to make scheduling decisions that reduce total transmission time. The resulting control-aware low-latency scheduling (CALLS) method is tested in numerous simulation experiments that demonstrate its effectiveness in meeting control-based goals under tight latency constraints relative to control-agnostic scheduling

Ossiculoplasty: A Prospective Study of 80 Cases

Introduction: The use of ossicular graft material in ossicular chain reconstruction has significantly improved hearing results hearing after tympanoplasty and tympanomastoid surgery for chronic otitis media. Today, otologists have a wide array of tools from which to choose, but may find it difficult to know which middle ear implant works best.   Materials and Methods: A prospective study of 80 patients who underwent ossiculoplasty was performed in the ear, nose, and throat (ENT) department at a tertiary health care facility from 2011 to 2013. Patients with chronic suppurative otitis media with an air-bone gap (ABG) of >25 dB with ossicular involvement were included in the study. Total ossicular replacement prosthesis (TORP), partial ossicular replacement prosthesis (PORP), and refashioned incus were used. Success was defined as ABG   Results: The majority patients were of middle age with moderate conductive hearing loss. Incus was the most susceptible ossicle. Overall success rate in this study was 80.0% with an average change of 15.76 dB in ABG.   Conclusion:  With continuing advances in our understanding of middle ear mechanics, the results of ossiculoplasty are improving and results can be very rewarding in experienced hands. Severity of preoperative ear discharge, preoperative mastoid cellularity, presence of disease, and surgical procedure proved to be significant prognostic factors. Autograft incus and PORP fared better when the malleus handle was present while TORP gave better results when the malleus handle was eroded