## 5 Architecture of the Proposed System
### Feature Selection  
Four extracted features--phonation, articulation, prosody, and their fusion--were compared. Table 2 summarizes all the calculated characteristics in proposed system along with the typical voice disorders in [PERSON]'s disease.  
The descriptors defined at the stage of generation of the features of each of the subsystems constitute the maximum set of features that describe a given problem. Nonetheless, given the very large number of measures of dysphonia, as a main symptom of PD, it is computationally infeasible to test all possible combinations. Having a large number of characteristics is a very serious problem. It increases the computational complexity of the algorithm and its memory requirements, extends the learning process, and increases the complexity of the classifier itself. However, most importantly, it also often causes a decrease in the number of correctly classified objects. The selection of features consists of selecting the best signal parameters in terms of distinguishability. Unfortunately, nothing short of a full, exhaustive (but intractable) search is guaranteed to produce the optimal feature set. As a compromise, in this study, we first apply a pre-selection filter in a separate system and then we employ the SFFS method (sequential floating forward), Relief, Fisher Score, \(F\)-tests, and Chi-square in integration feature sets [96; 97].  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Features** & **Symptoms of PD** & **Measured Feature** & **Additional Information** \\ \hline \multirow{8}{*}{Category} & Dysphonia & Jitter [\%] & \\  & Unstable vibrations of & Jitta [\(\mu\)s] & Irregular contraction of laryngeal muscles during \\  & vocal folds & RAP [\%], & sound production \\  & & PPQS [\%] & \\  & Roughness & Shimmer [\%] & \\  & Hoarseness & APQS [\%] & Reduced laryngeal control and degenerative changes in \\  & Dysphonia & APQS [\%] & laryngeal tissue \\  & & APQ11 [\%] & \\  & Exaggerated vocal tremor & PVI & Rapid and regular fluctuation of the \\  & & & fundamental frequency \\  & Dysphonia & PPE & New measure of dysphonia, which is robust to many \\  & Dysphonia & PPE & uncontrollable confounding effects \\  & Dysphonia & PPF & Unstable vibrations of vocal folds \\  & & & The degree of variability in fundamental frequency \\  & Dysphonia & PFR & contour that characterizes the functioning of the \\  & & & phonatory subsystem \\  & Dysphonia & NHR & Incomplete vocal fold closure \\  & Hoarseness & HNR, & Assessment of the ratio between periodic components \\  & Vocal weakness & HNR, & and non-periodic components \\ \hline \multirow{8}{*}{Category} & Hypokinetic & Spectral parameters & \multirow{2}{*}{Articulator movements} \\  & Dysarthria & (11 features) & \\  & Hypokinetic & \(F_{1},F_{2},F_{3},F_{4}\) & \\  & dysarthria & formants & Physical characteristics of the sound channel \\  & & & (resonant cavity) \\  & & \multicolumn{2}{c}{Snorousness coefficient} \\  & Dysfluency & Fraction of locally unvoiced & Information about the amount of aperiodicity in \\  & & pitch frames & the phonation \\ \hline \multirow{8}{*}{Category} & & Fundamental tone, \\  & & Duration of a sad statement, \\  & Monotonicity, & Duration of a joyful statement, \\  & Monoloudness & Number of “pa” syllables \\  & Hypoprosodia & uttered during a 5 s speech \\  & & & fragment, \\  & & Duration of the intervals \\  & & & between “pa” syllables \\ \hline \hline \end{tabular}
\end{table}
Table 2: List of all the calculated characteristics in the proposed system along with the typical voice disorders in [PERSON]’s disease.