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1

Estimation of information entropy based on its visualization

Cholewa M., Palys M.

Journal of Medical Informatics & Technologies

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2017

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Vol. 26

18--25

EN

This paper describes the method which allows an estimation of information entropy in the meaning of Shannon. The method is suitable to an estimation which sample has a higher value of information entropy. Several algorithms have been used to estimate entropy, assuming that they do it faster. Each algorithm has calculated this value for several text samples. Then analysis has verified which comparisons of the two samples were correct. It has been found that the probabilistic algorithm is the fastest and most effective in returning the estimated value of entropy.

2

Features reduction for computer user profiling based on mouse activity

Palys M., Wesołowski T. E.

Journal of Medical Informatics & Technologies

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2015

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Vol. 24

45--51

EN

The article is related to the computer systems security and to the problem of detecting the masqueraders, intruders who pretend to be legitimate users of computer systems, in particular. The research concerns computer user verification based on analysis of the mouse activity in computer system. The article presents an improvement of user verification method by introducing a new method of user proﬁling. The new user proﬁling method is based on the reduced number of features without the loss of information is introduced. The presented method of user proﬁling allows to simplify and speed up a user’s activity data analysis and is not causing the deterioration of intrusion detection. Additionally, a method of aggregating mouse activity basic events into a higher level events is described. This article presents the preliminary research and conclusions.

3

Mercury disk ultramicroelectrode based on the controlled-growth mercury drop system

Zon A., Palys M., Stojek Z.

Chemia Analityczna

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2002

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Vol. 47, No. 3

361-369

EN

A mercury disk ultramicroelectrode (MDUE) can be obtained using a controlled-growth mercury drop electrode (CGMDE) equipped with a very narrow-bore capillary (internal diameter <100 um). After dispensing mercury drop and then knocking it off, a slightly convex mercury disk is formed at the opening of the capillary, recessed by approximately Sum with respect to the capillary edge. The advantages of MDUE are: easily renewable surface and no interference by the support material. However, due to the free diffusion of the metals in Hg inside the capillary, it is not possible to accumulate the electrode reaction product, therefore anodic stripping experiments cannot be carried out. In the case of electrode processes involving soluble products, MDUE is superior to mercury film microelectrodes. Also, the recession of the mercury inside the capillary causes, at short times, some deviations of the voltammetric and chronoamperometric characteristics from the inlaid disk model. The voltammetric characterization of the mercury disk ultramicroelectrode was carried out using the model systems: Cd(2+)/Cd(Hg), TI(+)TI(Hg) and [Ru(NH(3))6](3+)[Ru(NH3)](2+). The results show, that the reproducibility of the voltammetric data is excellent; the relative standard deviation of the maximum current was 2.25%. Therefore, the MDUE can be used instead of mercury film ultramicroelectrode in all experiments that do not require the accumulation of traces of metals in mercury.

PL

Opracowano metodę otrzymywania dyskowych mikroelektrod rtęciowych wykorzystując kroplowąelektrodę rtęciową o kontrolowanym wzroście wyposażoną w specjanąkapilarę o wewnętrznej średnicy mniejszej niż 100 (am. Mikrodysk tworzono przez strącenie wytłoczonej z kapilary kropli. Był on lekko wybrzuszony oraz cofnięty wgłąb kapilary nie więcej niż 5 um. Zaletami takiej mikroelektrody dyskowej jest łatwo odnawialna powierzchnia i brak oddziaływania z materiałem podłoża. Jednakże konstrukcja elektrody uniemożliwia zatężanie śladów metali w rtęci: dyfundująone swobodnie wgłąb kapilary. Wybrano trzy układy red-ox do woltamperometrycznego scharakteryzowania rtęciowych mikrodysków: Cd(2+)/Cd(Hg), Tl+/Tl(Hg) and [RuCNH(3)](6)(+3)RuCNH(3))(6)](2+). Precyzja otrzymanych danychwoltamperometrycznych była bardzo dobra i względne odchylenie standardowe wynosiło2.25%.