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1

Random Reducts : A Monte Carlo Rough Set-based Method for Feature Selection in Large Datasets

Kruczyk M., Baltzer N., Mieczkowski J., Dramiński M., Koronacki J., Komorowski J.

Fundamenta Informaticae

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2013

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Vol. 127, nr 1-4

273--288

EN

An important step prior to constructing a classifier for a very large data set is feature selection. With many problems it is possible to find a subset of attributes that have the same discriminative power as the full data set. There are many feature selection methods but in none of them are Rough Set models tied up with statistical argumentation. Moreover, known methods of feature selection usually discard shadowed features, i.e. those carrying the same or partially the same information as the selected features. In this study we present Random Reducts (RR) - a feature selection method which precedes classification per se. The method is based on the Monte Carlo Feature Selection (MCFS) layout and uses Rough Set Theory in the feature selection process. On synthetic data, we demonstrate that the method is able to select otherwise shadowed features of which the user should be made aware, and to find interactions in the data set.

2

Alternate Copolymer of 3,4-Dioctyloxythiopheneand 2,2'-Bithiophene: Synthesis, Electronic and Spectroelectrochemical Properties

Pokrop R., Kasprzyk-Młynarczyk I., Zagorska M., Wielgus I., Mieczkowski J., Verilhac J., Wery J., Louarn G., Pron A.

Polish Journal of Chemistry

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2007

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Vol. 81, nr 5-6

731-744

EN

Anew electroactive polymer has been prepared by oxidative (electrochemical or chemical) polymerization of 3,4-dioctyloxy-2,2':5',2''-terthiophene. The polymer (PDOTT) is photoluminescent, emitting green light in solution and red light in the solid state. It can be used for the fabrication of organic field effect transistors, however the measured charge carriersmobilities in the transitor configuration ( = 7×10–6 cm2 V–1s–1) are lower than those found for the best polymers reported in the literature. PDOTT is much more promising for electrochemical and electrochromic applications since it shows perfectly reversible spectral response to potential switching. Moreover, in its doped state PDOTT is a strong near infrared absorber.

3

Photoconducting Properties of Fullerene Derivatized with a Biphenyl Moiety

Trzcińska K., Bilkova P., Szydłowska J., Mieczkowski J., Bilewicz R., Pociecha D., Gorecka E.

Polish Journal of Chemistry

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2006

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Vol. 80, nr 11

1899-1907

EN

The properties of low molecular weight molecules, in which the electron-acceptor fullerene unit was linked by malonate group and flexible long alkyl chains to two biphenyl-phenyl units, were studied. Cyclic voltammetry measurements showed five consecutive one-electron, reversible electro-reductions for the fullerene unit and a single two-electron, reversible electro-oxidation for biphenyl moiety. The two electron process indicated that two biphenyl moieties interacted; presumably folded conformation was formed with two electron donating moieties at close proximity. Along-living charge-separated state induced upon light absorption was confirmed by the ESR spectroscopy studies. These properties were responsible for observed photoconductivity of the studied compound.

4

Progress of Understanding Liquid Crystsls Made of Bent-Shaped Molecules

Mieczkowski J., Matraszek J.

Polish Journal of Chemistry

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2005

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Vol. 79 / nr 2

179-209

EN

Many strongly bent, so-called banana mesogenes have been synthesized and examined. These liquid crystalline materials are very attracted due to their unique properties and possible applications. In this paper we gathered information about bent-core mesogenes reported in the literature and described connections between molecular structure and polymorphism.

5

Synthesis of Crotonoyl, Cynamoyl and p-Methoxycynamoyl Derivatives of Camphoric Imide : Crystal and Molecular Structure

Matraszek J., Mieczkowski J., Cyrański M.

Polish Journal of Chemistry

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2000

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Vol. 74, nr 4

477-482

EN

Three derivatives of camphoric acid imide (crotonyl, cynamoyl and p-methoxycynamoyl) have been synthesized. Despite of a small number of heavy atoms, the absolute structure determination occured to be successful.