The uncertainty propagation in the calibration of single normal hot-wire anemometry probes used in the constant temperature mode is discussed in this paper. The two most used forms of calibration curve (the fourth order polynomial and the King’s law) are considered. The presented discussion is also useful for probes which are more complex than the single normal, such as the single yawed, the X, the V-shaped, the triple- and the four-wire probes. The uncertainties discussed here are important in mean flow velocity, and the discussion developed provides a notable opportunity to review some important aspects of the uncertainty propagation in any calibration involving curve fitting.

With regard to repeated assaults from Internet area on Linux servers where the monitoring and controlling system based on the TCP/IP protocol has been debugged and tested, there was designed and applied an effective firewall based on packet filtering for those servers. This firewall is able to defend the Linux server against most common attacks. Our own Linux distribution based on Debian/GNU distribution was designed and debugged. This distribution is loadable from a CD or a compact flash memory in case of an unfiltered Internet attack.

In this paper we introduce an approach for constructing statistical metrology tools with a Microsoft Excel based interface that uses the open source statistical package R as the computational engine. These metrology tools will enable Excel users to access a larger array of specialized statistical tools for metrology. We will describe our general approach and demonstrate one tool - an automated uncertainty calculator. This uncertainty calculator provides users with a simple and flexible tool for estimating measurement uncertainty using the methods outlined in the ISO Guide to the Expression of Uncertainty in Measurement, popularly known as the ISO GUM. The uncertainty calculator is easy to use for scientists who are comfortable with spreadsheets, can handle a variety of typical correlation structures, and performs a validity check on the results by simulating the coverage probabilities actually attained by the uncertainty intervals.

The paper deals with the problem of pointing out and mark the various kind of defects (mainly scars, wrinkles and fire brandings) of tanned calf leathers used in many industrial areas (e.g. household couches and car seats lining ones). In the first experiments here presented the authors try to use the same inspection method previously successfully applied to quality control of hands-made satin glasses, that is a two-dimensional wavelet-based de-noising technique of high resolution images of the leather under inspection; according to multiresolution analysis, this method produces a suitable number of decomposition levels of the image, then it carries out a thresholding operation on details and finally, using the threshold levels estimated considering the actual noise level, it assesses and mark the various kind of defects. The final aim of the work is the realization of an automatic and in-line computer vision system for leather analysis capable to accurately inspect and mark the defective areas of the analyzed leather specimens before they enter the production chain.

In the field of metrology it is common practice to approximate the results of a measurement by functions modelling physical facts. The most simple form of such an approximation is the linear fit. This article presents five different methods of linear fit in R² by working out the characteristic features of these methods like scale unit invariance. The author's intention is to be helpful in finding the most useful method from case to case.