An important step for active noise control (ANC) systems to be practical is to develop model independent ANC (MIANC) systems that tolerate parameter variations in sound fields. Reliabilities and stabilities of many MIANC systems depend on results of online system identifications. Parameter errors due to system identifications may threaten closed-loop stabilities of MIANC systems. A self-learnin...

Ventilation systems installed in buildings usually generate low-frequency noise because the passive silencers commonly used to attenuate the ventilation noise are not effective in the lowfrequency range. A method proven to effectively reduce low-frequency noise in a wide variety of applications is active noise control (ANC). A feedforward ANC system applied to duct noise normally uses a referen...

The need to eliminate unwanted sounds is greater, as this is an expression of the limited tolerance that we have as individuals to the perception of sounds generated by industrial equipment, appliances and some general properties that are unpleasant for most people. Vibrations mechanical engines in operation, digging machinery and electricity generators, are just a few examples of processes or ...

Industrial noise can be successfully mitigated with the combined use of passive and Active Noise Control (ANC) strategies. In a noisy area, a practical solution for noise attenuation may include both the use of baffles and ANC. When the operator is required to stay in movement in a delimited spatial area, conventional ANC is usually not able to adequately cancel the noise over the whole area. N...

This paper presents the comparative performance analysis of two adaptive algorithms to control the attenuation of acoustic noise. Active noise control (ANC) is one of the most popular applications for adaptive filters. The basic idea behind the active control of acoustic noise is to inject a secondary sound (anti-noise) into an environment so as to cancel the primary sound using destructive int...

In this paper, we present the development and evaluation of an integrated active noise control (ANC) communication headsets. This integrated system provides cancellation of noise that corrupted both the transmitted near-end speech and the received far-end speech. It utilizes an adaptive feedback ANC filter to reduce acoustic noise that corrupts the far-end signal inside the ear cups of headsets...

In this paper existing classical and advanced techniques of active acoustic noise cancellation (ANC) in ducts are collected and compared. The laboratory plant used in experience showed a linear behaviour and so the advanced techniques were not used. Due to delay on the plant, the feedback classical techniques could not be applied. The best results were obtained with the modified filtered-refere...

BACKGROUND Recent papers on monitoring of health services affirmed that while antenatal care (ANC) is an effective measure, quality is still a problem. Quality in maternal services "…involves providing a minimum level of care to all pregnant women…" Yet adherence to a minimum level of recommended ANC content appears to be unmet. Comprehensive review of ANC content rendered in environments with ...

OBJECTIVE To compare HIV seroprevalence estimates obtained from antenatal care (ANC) sentinel surveillance surveys in Ethiopia, Kenya, Malawi, Tanzania and Uganda with those from population-based demographic and health surveys (DHS) and AIDS indicator surveys (AIS). METHODS Geographical information system methods were used to map ANC surveillance sites and DHS/AIS survey clusters within a 15-...