Resolution Trees with Lemmas: Resolution Refinements that Characterize DLL Algorithms with Clause Learning

Resolution refinements called w-resolution trees with lemmas (WRTL) and with input lemmas (WRTI) are introduced. Dag-like resolution is equivalent to both WRTL and WRTI when there is no regularity condition. For regular proofs, an exponential separation between regular dag-like resolution and both regular WRTL and regular WRTI is given. It is proved that DLL proof search algorithms that use clause learning based on unit propagation can be polynomially simulated by regular WRTI. More generally, non-greedy DLL algorithms with learning by unit propagation are equivalent to regular WRTI. A general form of clause learning, called DLL-Learn, is defined that is equivalent to regular WRTL. A variable extension method is used to give simulations of resolution by regular WRTI, using a simplified form of proof trace extensions. DLL-Learn and non-greedy DLL algorithms with learning by unit propagation can use variable extensions to simulate general resolution without doing restarts. Finally, an exponential lower bound for WRTL where the lemmas are restricted to short clauses is shown

Odhad únavy člověka: využitelnost systémů dopravy ve vnitřním prostředí

Fatigue monitoring is nowadays domain in traffic and transportation (e.g. system for driver's sleepness monitoring in cars or in trains). People working in offices are affected by fatigue too, but there is no general system that is able to monitor it. The fatigue in offices can cause decreasing work productivity or security risks in the industry. This review article compares the advantages and disadvantages of approaches used in traffic (e.g. an eye-movement tracking, driver activity) in internal environment (in buildings) with focus on people that work in offices with a computer. Because of the greater possibility of movement, it can not be enough. People are in offices longer than in cars and this causes that they are more affected by the quality of the internal environment. It should be useful to include this information in a system for fatigue monitoring. It can result in a system that is able to quantify fatigue level from both biological and environment variables.Sledování únavy člověka je dnes hlavně doménou dopravy (systémy pro sledování řidiče v moderních automobilech, systémy pro strojvedoucí, atd.). U lidí pracujících v kancelářích se únava prakticky nesleduje, přestože její vliv může mít negativní dopad nejen na kvalitu a produktivitu práce, ale v případě osob na velínech v průmyslu také možná bezpečností rizika. Tato rešeršní práce se zabývá možnostmi aplikace systémů pro monitoring únavy řidiče automobilu (např. z pohybu očí, aktivit při řízení) na osoby pracující v kancelářských prostorách. To se vzhledem k možnostem pohybu po kanceláři jeví jako nedostatečné. Protože člověk tráví v kanceláři typicky více času než v automobilu, ovlivňuje jej výrazněji vnitřní prostředí budov, které je vhodné do odhadu únavy také zahrnout. Výsledkem tak může být systém kvantifikující míru únavy zohledněním jak vnitřního prostředí, tak vybraných biologických signálů člověka snímaných na pracovním místě

Morphological and physiological profile of elite basketball players in Belgium

PURPOSE: The present study aimed to gain insight into the physiological profile of elite basketball players in Belgium in relation to their position on the field. METHODS: The group consisted of 144 players, divided into 5 groups according to position (point guards [PG], shooting guards [SG], small forwards [SF], power forwards [PF] and centers [C]). The anthropometrics were measured and the subjects underwent fitness tests (incremental running test, 10m-sprint,5x10m,Squat and Counter Movement Jump, isokinetic test) to obtain insight into endurance, speed, agility and power. The parameters of these tests were compared among the different positions by means of one-way variance analysis (MANOVA). Tukey post hoc-tests where performed in case of a significant MANOVA. RESULTS: It was observed that C were taller, heavier and had a higher body fat percentage compared to PG and SG. For the anaerobic sprint test C were slower compared to the other positions. For the 5x10m the PG and SG were faster than SF and PF. For the jump test C displayed a significantly lower absolute performance compared to the other positions. PG and SG had a higher VO2peak and speed at the anaerobic threshold compared to PF and C. The isokinetic strength test showed that the quadriceps muscle group of C could exert a higher torque during the knee extension compared to the other positions. CONCLUSIONS: The present study showed that the physiological profile of elite players in the Belgian first division differs among the position on the field. More specific, guards were characterized by a high endurance, speed and agility, whereas centers and power forwards showed a higher muscular strength compared to the other positions

Surface Potentials of Hydrophobic Microdomains in Aqueous Solutions of Poly(dimethyldiallylammonium-co-methyl-n-dodecyldiallylammonium salts) with Different Counterions. Evidence for the Existence of a Critical Aggregation Concentration

The solvatochromic acid-base indicator 1-hexadecyl-4-[(oxocyclohexadienylidene)ethylene]-1,4-dihydropyridine (HOED) was used to determine surface potentials (Y) of micelles formed from methyldiallyl-ndodecylammonium salts containing different counterions (MDDAX, X- = Cl, Br, I, benzoate, salicylate). Y decreased in the order Cl > Br > I > benzoate, salicylate consistent with conductometrically determined values for the counterion binding. HOED was also used to probe the microdomains formed in aqueous solutions of poly(dimethyldiallylammonium-co-methyl-n-dodecyldiallylammonium salts) containing different counterions (Copol C1-12 90/10 X). A similar dependence of Y on the nature of the counterion was found. Raising the temperature led to higher values of Y, while increasing the polysoap concentration appeared to lower the surface potentials for all polysoaps. With the exception of Copol C1-12 90/10 I and Sal, an additional peak in the UV-vis absorption spectrum of the probe was observed which was attributed to the aggregation of probe molecules on nondomain forming strains of the polysoap. Support for this conclusion was obtained from the observation that the intensity of the additional peak greatly decreased upon increasing the polysoap concentration. This behavior can be reconciled with the occurrence of a critical aggregation concentration. The sudden rise of the aggregation numbers of Copol C1-12 90/10 Br and benzoate at ca. 10 mM, leading to a constant value at higher concentrations, provides additional evidence for this conclusion

3D Reconstruction of CT Scans For Visualization in Virtual Reality

Computed tomography allows analyzing the internal structure of an object, which is useful especially in medicine. The standard visualization displays scans in the 2D plane. 3D reconstruction of scans provides a complex image of the morphology of the scanned object. Matlab is a software commonly used for image processing and analysis. It includes Medical Image Processing Toolbox for displaying data from CT scan in DICOM format. However, it is not possible with this toolbox to export the dataset of the image as a 3D object. Therefore, the aim of the paper is the implementation of a toolbox for loading and displaying data as a 3D reconstruction. This toolbox allows the user to export the data in OBJ or STL format. That allows the user (i) to visualize the 3D models in virtual reality and (ii) to prepare the model for 3D printing. The OBJ model is imported to Blender and then exported out with a texture as an object file. In Unity, we created a 3D scene and imported model. The advantage of displaying the 3D model in virtual reality is a more realistic view of the shape and dimension of an object.Výpočetní tomografie umožňuje studovat vnitřní strukturu objektu, což je využíváno především v medicíně. Standardní zobrazovací techniky promítají snímky ve 2D rovině. 3D rekonstrukce snímků přináší komplexní pohled na morfologii snímané tkáně. Matlab je software běžně užívaný v oblasti zpracování a analýze obrazových dat. Zároveň obsahuje nástroj “Image Procesessing Toolbox”, který umožňuje zobrazit CT snímky uchované ve formátu DICOM. Tento nástroj však neumožňuje vyexportovat zobrazený model jako 3D objekt. Cílem tohoto projektu bylo vytvoření nástroje pro načítání a zobrazení zrekonstruovaných 3D modelů. Tento nástroj umožňuje uživateli vyexportovat data v OBJ nebo STL formátu, který umožňuje (i) vizualizovat 3D model ve virtuální realitě a (ii) připravit model vhodný pro 3D tisk. V editor Unity byla vytvořena 3D scéna a do ní byl importován vygenerovaný model. Výhodou zobrazení 3D modelu ve virtuální realitě je přirozený pohled na prostorové uspořádání objektu

Effect of selected luminescent layers on CCT, CRI, and response times

Phosphors have been used as wavelength converters in illumination for many years. When it is excited with blue light, the frequently used yttrium aluminium garnet doped with cerium (YAG:Ce) phosphor converts a part of blue light to a wideband yellow light, resulting in the generated light having a white color. By combining an appropriate concentration of the YAG:Ce phosphor and blue excitant light, white light of a desired correlated color temperature (CCT) can be obtained. However, this type of illumination has a lower color rendering index value (CRI). In an attempt to improve the CRI value, we mixed the YAG:Ce phosphor with europium-doped calcium sulfide phosphor (CaS:Eu), which resulted in a considerably increased CRI value. This article examines an experiment with luminescent layers consisting of a mixture of selected phosphors and polydimethylsiloxane (PDMS). Different thicknesses in these layers were achieved by changing the speed of rotation during their accumulation onto laboratory glass using the method of spin coating. The spectral characteristics of these luminescent layers as they were excited with blue light emitting diode (LED) and laser diode (LD) were then determined. A suitable combination of the YAG:Ce phosphor with a phosphor containing europium, as it was excited with a blue LED, yielded a source of white light with a CRI value of greater than 85. The response time in the tested luminescent layers to a rectangular excitant impulse (generated by a signal generator and transmitted by LD) was also measured in order to examine their potential use in visible light communications (VLC).Web of Science1213art. no. 209