647 research outputs found

    The Complexity of Finding Reset Words in Finite Automata

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    We study several problems related to finding reset words in deterministic finite automata. In particular, we establish that the problem of deciding whether a shortest reset word has length k is complete for the complexity class DP. This result answers a question posed by Volkov. For the search problems of finding a shortest reset word and the length of a shortest reset word, we establish membership in the complexity classes FP^NP and FP^NP[log], respectively. Moreover, we show that both these problems are hard for FP^NP[log]. Finally, we observe that computing a reset word of a given length is FNP-complete.Comment: 16 pages, revised versio

    Thermal Conductivity of High Performance Concrete in Wide Temperature and Moisture Ranges

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    The thermal conductivity of two types of high performance concrete was measured in the temperature range from 100 °C to 800 °C and in the moisture range from dry material to saturation water content. A transient measuring method based on analysis of the measured temperature fields was chosen for the high temperature measurements, and a commercial hot wire device was employed in room temperature measurements of the effect of moisture on thermal conductivity. The measured results reveal that both temperature and moisture exhibit significant effects on the values of thermal conductivity, and these effects are quite comparable from the point of view of the magnitude of the observed variations

    Temperature and Moisture Dependence of the Specific Heat of High Performance Concrete

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    The specific heat of two types of high performance concrete was measured in the temperature range from 20 °C to 1000 °C and in the moisture range from dry material to saturation water content. A nonadiabatic method was chosen instead of classical adiabatic treatments in order to meet the requirements following from the large representative elementary volume of the materials. The measured results reveal a significant temperature effect on the specific heat value. The influence of moisture is less important than the influence of temperature, but is also not negligible

    Thermal and Hygric Expansion of High Performance Concrete

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    The linear thermal expansion coefficient of two types of high performance concrete was measured in the temperature range from 20 °C to 1000 °C, and the linear hygric expansion coefficient was determined in the moisture range from dry material to saturation water content. Comparative methods were applied for measurements of both coefficients. The experimental results show that both the effect of temperature on the values of linear thermal expansion coefficients and the effect of moisture on the values of linear hygric expansion coefficients are very significant and cannot be neglected in practical applications

    Finitely generated ideal languages and synchronizing automata

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    We study representations of ideal languages by means of strongly connected synchronizing automata. For every finitely generated ideal language L we construct such an automaton with at most 2^n states, where n is the maximal length of words in L. Our constructions are based on the De Bruijn graph.Comment: Submitted to WORDS 201

    Comparison of the Capacitance Method and the Microwave Impulse Method for Determination of Moisture Profiles in Building Materials

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    A comparison of the capacitance method and the microwave impulse method for the determination of moisture profiles in three typical porous building materials is presented in this paper. The basic principles of the measuring methods are given. The calibration process is described in detail. On the basis of the measured results, it can be concluded that the capacitance method provides better accuracy in the range of lower moisture content than to the microwave impulse method, which is more accurate for the highest values of moisture content.

    ÚČINNOSŤ DEZINFEKČNÉHO PRÍPRAVKU DUSEPT NA G- A G+ BAKTÉRIE TEPELNE OŠETRENÉHO MLIEKA

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    We were evaluating the effectiveness of disinfecting appliance Dusept on mixture of G+ and G- bacteria and on the micro-organisms of heat-treated milk by three methods. By using the qualitative method effective action of 2% reagent was found on mixture of G+ and G- bacteria. By the qualitative method with carrier the 2% reagent was also effective on the mixture of G+ and G- bacteria, 1% and 0,1% reagents were not effective. The 2% reagent was not effective on the micro-organisms of milk on a carrier. The 2% solution was effective when applying the quantitative method by 20 minutes actuation on bacteria contained in milk.V experimente sme hodnotili účinnosť dezinfekčného prípravku na báze chlóru tromi metódami na zmes G+ a G- baktérií a na mikroorganizmy obsiahnuté v pasterizovanom mlieku. Pri použití kvalitatívnej platňovej metódy bolo účinné pôsobenie 2 %-ného roztoku na zmes G+ a G- baktérií. Pri kvalitatívnej metóde s použitím skleneného nosiča bol 2 %-ný roztok taktiež účinný na zmes G+ a G- , 1 %-ný a 0,1 %-ný roztok nebol účinný. Pre mikroorganizmy mlieka na nosiči 2 %-ný roztok bol neúčinný. Pri kvantitatívnej metóde bol 2 %-ný roztok po 20 minútovom pôsobení na baktérie obsiahnuté v mlieku účinný

    Evaluation of Water Resistance and Diffusion Properties of Paint Materials

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    A simple method is presented for evaluating the water-proofness quality of paints on lining materials. The method is based on measuring the integral capillarity in dependence on time, and then comparing this value to the value determined for the basic lining material. Measurements of the effective water vapor permeability then provide information on the risk of condensation which may increase after applying the paint. A practical application of the method is performed with four Karlocolor paints on glass concrete substrates. All the Karlocolor paints are found to be very effective materials for driven rain protection. The diffusion properties of all the paints are found to be excellent
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