Dithering Research Articles

Application of dithering control for the railway wheel squealing noise mitigation

A new methodology for mitigation of the wheel squealing is proposed and investigated based on the dithering control. The idea can be applied in railway lines particularly in urban areas. The idea is clearly presented, and applied to a validated model. A full-scale model including the vehicle, curved track and wheel/rail contact is developed in the time domain to analyze the possibility and level of wheel squeal noise. Comparing the numerical results with a field test, the model is validated in different levels namely i) occurrence, ii) squealing frequency and iii) noise level. Two different approaches are proposed a) dithering of the wheel with piezoelectric patches and b) dithering of the rail with piezoelectric stacks. The noise level as well as the wheel responses is compared after applying the control strategy. A parametric study is carried out and effect of the dithering voltage and frequency on the squealing noise is investigated. It is found that both the strategies perform quite effectively within the saturating threshold of piezoelectric actuators.

Last days for US polar bear dithering?

Last days for US polar bear dithering?

Joint watermarking and compression using scalar quantization for maximizing robustness in the presence of additive Gaussian attacks

In joint watermarking and compression (JWC), a key process is quantization which embeds watermarks into a host signal while digitizing the host signal subject to requirements on the embedding rate, compression rate, quantization distortion, and robustness. Using fixed-rate scalar quantization for watermarking and compression, in this paper, we mainly consider how to design binary JWC systems to maximize the robustness of the systems in the presence of additive Gaussian attacks under constraints on the compression rate and quantization distortion. We first investigate optimum decoding of a binary JWC system, and demonstrate by experiments that in the distortion-to-noise ratio (DNR) region of practical interest, the minimum distance (MD) decoder achieves performance comparable to that of the maximum likelihood decoder in addition to having advantages of low computation complexity and being independent of the statistics of the host signal. We then present optimum binary JWC encoding schemes using fixed-rate scalar quantization and the MD decoder. Simulation results show that optimum binary JWC systems using nonuniform quantization are better than optimum binary JWC systems using uniform quantization. Furthermore, in comparison with separate watermarking and compression systems, optimum binary JWC systems using nonuniform quantization achieve significant DNR gains in the DNR region of practical interest. Finally, spread transform dither modulation is applied to improving the robustness of the JWC systems at low DNRs.

Visual cryptography for gray-level images by dithering techniques

A (k,n)-threshold visual cryptography scheme is proposed to encode a secret image into n shadow images, where any k or more of them can visually recover the secret image, but any k-1 or fewer of th...

We're doomed to dither

We're doomed to dither

We're doomed to dither

We're doomed to dither

Australia: Government dithers on scrapping co-payment

Australia: Government dithers on scrapping co-payment

Dithering with Dithranol - Paste or Stick?

Dithering with Dithranol - Paste or Stick?

Dithering on the deadline

Dithering on the deadline

Reply to ‘Comment on Use of synchronised dither in pseudorandom-sequence testing’

Reply to ‘Comment on Use of synchronised dither in pseudorandom-sequence testing’

Dither--a way to reduce undesirable fright behavior in ethological studies.

Zusammenfassung Wie stark Fluchtstimmung (“Furcht”) das Verhalten von Versuchstieren in ethologischen Untersuchungen storen kann, ist zwar wohl vielen bekannt, wird aber selten erortert oder in Veroffentlichungen erwahnt. Die Beobachter setzen die Tiere meist entweder der vollen Storung durch den Laborbetrieb aus oder schliesen sie weitestgehend von allen moglichen Storreizen ab. Im ersten Fall fehlt die Kontrolle uber wichtige Storfaktoren, im zweiten werden vor allem Wirbeltiere oft so furchtsam, das sie das meiste Verhalten unterdrucken. In Untersuchungen an verschiedenen Fischarten hat sich folgender Ausweg sehr bewahrt: Man setzt zum Versuchstier hinter eine durchsichtige Trennwand andersartige Tiere, die sich standig gleichmasig bewegen, fur das Versuchstier aber ohne Interesse sind.

A missile adaptive roll autopilot with new Dither principle

A missile adaptive roll autopilot with new Dither principle

Dithering devices in the classroom: How to succeed in shaking up a campus by really trying.

Dithering devices in the classroom: How to succeed in shaking up a campus by really trying.

Don't Be in a Dither?

Don't Be in a Dither?

To shiver: to dither: to nerl: to chatter

To shiver: to dither: to nerl: to chatter