In order to find silent pauses in all recordings, an ITU-T G.729b compliant voice activity detector (VAD) was used, which relies on full band energy, low band energy, zero-crossing rate and a spectral measure to decide whether a 10-ms segment contains voice.
For tobacco smoking, the method developed by Peto et al (1992) was used, which relies on the ratio between observed incidence of lung cancer in smokers and that in non-smokers, to calibrate the risk.
It has recently been shown 17, 22, 23 that it is possible to extend the pure shift methods currently used, which rely on stitching together separate measurements of short periods of decoupled signal, to real-time acquisition, in which homonuclear couplings are periodically refocused, by applying appropriate spin manipulations during the acquisition of a single free-induction decay.
We report full mathematical specifications of the algorithm used, which relies on an internal model of the child's knowledge in a multidimensional "learning space" consisting of three difficulty dimensions: numerical distance, response deadline, and conceptual complexity (from non-symbolic numerosity processing to increasingly complex symbolic operations).
Another important difference between MCFS and RF is that while in the former individual trees are built on training samples drawn without replacement from the original set of samples (and are evaluated on the remaining samples) in the latter bootstrap techniques are used which rely on sampling with replacement.
These studies generally used questionnaires which relied on participants' retrospective reconstruction of mobile phone use.
To facilitate this second approach, we sought to develop an algorithm that was easy to use and which relied only on a relatively small number of variables that are easily obtained from available records or from the patient.
For example, cultural probes are inherently playful and ambiguous in nature and need to be re-designed and adapted to the cultural settings in which they are used, which has previously relied on the skills of a professional designer [ 28].
In order to optimize alignment parameters or measure the quality of alignments, a cost function was used which does not rely on any reference or ideal alignments.
The approach used here, which relies on published information to access a large number of cases (the "price to pay" in terms of data quality being here censorship), could be easily adapted to other vaccine-preventable diseases.
