"various unknown" is a correct and usable phrase in written English.
It can be used when referring to any number of unknown elements, whether concrete or abstract. For example, "This project requires the solving of various unknown mathematical equations."
The optimization process is run to adjust these various unknown parameters in order to match production history.
The result will ultimately help to estimate the paste volumes of various unknown AAB mixtures produced from different sources of fly ash and slag.
Without knowledge of the contour of workpiece and gains of the controller in advance, the adaptive controller performs well for various unknown contours.
The remaining 9% was considered as unaccountable, which might be released due to volatilizations or lost due to various unknown reasons.
The basic role of the receiver is to decode the information bits from the received signal which is affected by various unknown factors, such as the channel response and receiver noise.
It is expected that the result of this study will ultimately help to estimate the paste volumes of various unknown AAB mixtures produced from different sources of fly ash and slag.
The wines of the Friuli-Venezia Giulia region (of which Trieste is the capital) are various, relatively unknown outside Italy and well worth exploring.
The reasons for the decay and persistence of links remain various and unknown.
The difficulty in the definition may be due to the various or unknown causes of oscillations such that different sources may possibly have different mathematical models.
For various reasons (unknown constants or parameters, unclear description of calculation, etc)., it was possible to evaluate only 16 equations out of 34 equations.
Moreover, the system inputs are assumed to be random white noises, modeling all the various and unknown influences on the system, either environmental or operational.
