Symbolic Semantics for Probabilistic Programs

We present a new symbolic execution semantics of probabilistic programs that include observe statements and sampling from continuous distributions. Building on Kozen’s seminal work, this symbolic semantics consists of a countable collection of measurable functions, along with a partition of the state space. We use the new semantics to provide a full correctness proof of symbolic execution for probabilistic programs. We also implement this semantics in the tool symProb, and illustrate its use on examples

Degradation of organic pollutants by advanced oxidation processes (AOPs)

A number of AOPs, i.e. H2O2/UV, O3/UV, O3/OH[-], Fe[3+]/H2O2, H2O2/O3 and TiO2/UV, were investigated for their potential application to the removal of organic pollutants from water. Consideration was given to the influence of the free radicals forming in the course of various AOPs on the quality of surface water treated with a conventional train which included preozonation, coagulation and rapid sand filtration. In the reported experiments, use was made of the H2O2/UV, O3/UV and H2O2/O3 methods, practicable in water treatment. For comparison, the effect of chemical oxidation (carried out with each of the reagents separately) on the quality of the treated water was also studied. Of all the AOPs used in the experiments, the H2O2/UV was found to be the most efficient. With an H2O2 dose ranging from 10 to 15 g/m[3] and with an UV (254 nm) exposure time of about 1 h, the reduction of coloured matter, UV absorbance, COD and TOC amounted to 83.4%, 99.3%, 71.6% and 61.1%, respectively. The improved water quality obtained primarily due to the use of the H2O2/UV method will noticeably improve the conditions and performance of the GAC bed, which is conventionally applied after the completion of the said process

Methods of voltage unbalance estimation in electric power networks

Methods of voltage unbalance estimation based on the theory of symmetrical components and the method of differential — angular coefficients of asymmetry have been discussed. It has been proposed the last one to estimate the asymmetry of square absolute voltage value, as useful for distorted processes

Advantages of changing 3-phase ARC furnaces asymmetry estimation criteria in international and european standards

The criteria for estimating the asymmetry of arc furnace circuit impedances, referring to the theory of symmetrical components, have been presented. In contrast to the criteria recommended as yet by IEC and CENELEC, they give homogeneous estimation of asymmetry of circuit impedances, heating powers and unbalance of arc currents. Moreover they make it possible to take into account functional dependences among them and, consequently, to improve the analysis of unbalanced operation states of EAF, as well as their balancing

Hierarchical clustering of metamodels for comparative analysis and visualization

Many applications in Model-Driven Engineering involve processing multiple models or metamodels. A good example is the comparison and merging of metamodel variants into a common metamodel in domain model recovery. Although there are many sophisticated techniques to process the input dataset, little attention has been given to the initial data analysis, visualization and filtering activities. These are hard to ignore especially in the case of a large dataset, possibly with outliers and sub-groupings. In this paper we present a generic approach for metamodel comparison, analysis and visualization as an exploratory first step for domain model recovery. We propose representing metamodels in a vector space model, and applying hierarchical clustering techniques to compare and visualize them as a tree structure. We demonstrate our approach on two Ecore datasets: a collection of 50 state machine metamodels extracted from GitHub as top search results; and ∼ ∼100 metamodels from 16 different domains, obtained from AtlanMod Metamodel Zoo

Microbial growth in cement-lined ductile cast-iron water-pipe networks

Rozwój bakterii w sieciach i instalacjach wodociągowych zależy od zawartości środka dezynfekcyjnego w wodzie, warunków hydrodynamicznych i szybkości poboru związków pokarmowych przez mikroorganizmy, a także od obecności osadów korozyjnych. W pracy przed-stawiono wyniki badań modelowych nad rozwojem mikroorganizmów w niedezynfekowanej wodzie podziemnej podczas jej przepływu i stagnacji w przewodzie żeliwnym z powłoką cementową. Zidentyfikowano różnorodność bakterii i określono ich liczbę w wodzie dopływającej do układu badawczego, w wodzie przebywającej w tym układzie oraz w biofilmie pobranym z wnętrza przewodu, zarówno podczas stagnacji wody, jak i przy przepływie wody z prędkością 0,1 m/s. Stwierdzono znaczne zwiększenie liczebności mikroorganizmów w wodzie z układu badawczego i w biofilmie porastającym wewnętrzną powierzchnię przewodu, szczególnie w warunkach przepływu wody. Zaobserwowano także zmniejszenie zawartości żelaza w wodzie, przy jednoczesnym wzroście bakterii utleniających Fe(II) w wodzie i biofilmie.Bacterial growth in water-pipe networks and related infrastructure is influenced by a variety of factors such as the disinfectant concentration in the water being treated, the hydrodynamic regime, the rate of nutrient utilization by the microorganisms, and the presence or absence of corrosion scales and deposits. This paper presents the results of model investigations into microbial growth in non-disinfected groundwater during flow and stagnation in a cement-lined cast-iron pipe. Diverse bacterial species were identified and their counts were assessed not only in the water before inflow and during residence in the experimental set-up, but also in the bio-film collected from the pipe interior during water stagnation and during water flow with a velocity of 0.1 m/s. It was found that the number of microorganisms increased significantly both in the water residing within the experimental set-up and in the biofilm growing on the internal surface of the pipe, specifically under conditions of water flow. It was also observed that the iron content of the water decreased with the increase in the number of Fe(II) oxidizing bacteria in the water and the biofilm