42 research outputs found

    The Krohn-Rhodes Logics

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    We present a new family of modal temporal logics of the past, obtained by extending Past LTL with a rich set of temporal operators based on the theory by Krohn and Rhodes for automata cascades. The theory says that every automaton can be expressed as a cascade of some basic automata called prime automata. They are the building blocks of all automata, analogously to prime numbers being the building blocks of all natural numbers. We show that Past LTL corresponds to cascades of one kind of prime automata called flip-flops. In particular, the temporal operators of Past LTL are captured by flip-flops, and they cannot capture any other prime automaton, confining the expressivity within the star-free regular languages. We propose novel temporal operators that can capture other prime automata, and hence extend the expressivity of Past LTL. Such operators are infinitely-many, and they yield an infinite number of logics capturing an infinite number of distinct fragments of the regular languages. The result is a yet unexplored landscape of extensions of Past LTL, that we call Krohn-Rhodes Logics, each of them with the potential of matching the expressivity required by specific applications

    Stream Reasoning in Temporal Datalog

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    In recent years, there has been an increasing interest in extending traditional stream processing engines with logical, rule-based, reasoning capabilities. This poses significant theoretical and practical challenges since rules can derive new information and propagate it both towards past and future time points; as a result, streamed query answers can depend on data that has not yet been received, as well as on data that arrived far in the past. Stream reasoning algorithms, however, must be able to stream out query answers as soon as possible, and can only keep a limited number of previous input facts in memory. In this paper, we propose novel reasoning problems to deal with these challenges, and study their computational properties on Datalog extended with a temporal sort and the successor function (a core rule-based language for stream reasoning applications)

    Improved Answer-Set Programming Encodings for Abstract Argumentation

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    The design of efficient solutions for abstract argumentation problems is a crucial step towards advanced argumentation systems. One of the most prominent approaches in the literature is to use Answer-Set Programming (ASP) for this endeavor. In this paper, we present new encodings for three prominent argumentation semantics using the concept of conditional literals in disjunctions as provided by the ASP-system clingo. Our new encodings are not only more succinct than previous versions, but also outperform them on standard benchmarks.Comment: To appear in Theory and Practice of Logic Programming (TPLP), Proceedings of ICLP 201

    The Window Validity Problem in Rule-Based Stream Reasoning

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    Rule-based temporal query languages provide the expressive power and flexibility required to capture in a natural way complex analysis tasks over streaming data. Stream processing applications, however, typically require near real-time response using limited resources. In particular, it becomes essential that the underpinning query language has favourable computational properties and that stream processing algorithms are able to keep only a small number of previously received facts in memory at any point in time without sacrificing correctness. In this paper, we propose a recursive fragment of temporal Datalog with tractable data complexity and study the properties of a generic stream reasoning algorithm for this fragment. We focus on the window validity problem as a way to minimise the number of time points for which the stream reasoning algorithm needs to keep data in memory at any point in time

    STRUCTURAL ANALYSIS FOR AN HISTORICAL R.C. TALL BUILDING RESTORATION

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    n this paper a detailed structural analysis (under the seismic and wind loads) of an historical tall building in Milan is carried out. It’s one of the first tall building (109 m height) realized in Italy in the 56- 59 years, and an important restoration is affecting it with intended use change (from office to luxury hotel and residences). To investigate the characteristics of concrete several destructive, non-destructive and combined tests are conducted. Moreover, additional destructive and chemical tests on the reinforced bars steel are performed too. Some finite elements models (FEMs) are implemented by using beam and plate elements considering two different boundary conditions (base fixed and elastic soil by Winkler model) and the interaction of the close existing lower constructions presence. In all of the FEMs, the materials characteristics are assigned basing on the tests results and a their subsequent statistical interpretation. The seismic load, implemented by a response spectrum analysis, and the wind load are applied in according to the Italian Construction Code (NTC). The structural resistance verifies are carried out in terms of shear and combined compressive-bending stress, whereas further ductility verifies are conducted considering appropriate nonlinear behaviours of the concrete and the steel bars. Finally some hypothesis to improve the structural behaviour under the lateral loads are proposed by considering cost-benefit analysis

    Temporal Logic Monitoring Rewards via Transducers

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    In Markov Decision Processes (MDPs), rewards are assigned according to a function of the last state and action. This is often limiting, when the considered domain is not naturally Markovian, but becomes so after careful engineering of extended state space. The extended states record information from the past that is sufficient to assign rewards by looking just at the last state and action. Non-Markovian Reward Decision Processes (NRMDPs) extend MDPs by allowing for non-Markovian rewards, which depend on the history of states and actions. Non-Markovian rewards can be specified in temporal logics on finite traces such as LTLf/LDLf, with the great advantage of a higher abstraction and succinctness; they can then be automatically compiled into an MDP with an extended state space. We contribute to the techniques to handle temporal rewards and to the solutions to engineer them. We first present an approach to compiling temporal rewards which merges the formula automata into a single transducer, sometimes saving up to an exponential number of states. We then define monitoring rewards, which add a further level of abstraction to temporal rewards by adopting the four-valued conditions of runtime monitoring; we argue that our compilation technique allows for an efficient handling of monitoring rewards. Finally, we discuss application to reinforcement learning

    Probucol treatment is associated with an ABCA1-independent mechanism of cholesterol efflux to lipid poor apolipoproteins from foam cell macrophages

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    Objective Probucol is a cholesterol-lowering agent whose ability to prevent atherosclerosis is currently under study. Herein, we investigate the putative mechanism of probucol by observation of changes in cellular cholesterol efflux and lipid droplet morphology in macrophages. Results The inhibitory activity of probucol was assessed in non-foam or foam cell macrophages expressing ABCA1 generated by treatment with fetal calf serum (FCS) alone or in combination with acetylated LDL, respectively. Probucol inhibited cholesterol efflux to apolipoprotein A-I (apoA-I) by 31.5±0.1% in THP-1 non-foam cells and by 18.5±0.2% in foam cells. In probucol-treated non-foam THP-1 cells, nascent high-density lipoprotein (nHDL) particles with a diameter < 7 nm were generated, while in probucol-treated THP-1 foam cells nHDL particles of > 7 nm in diameter containing cholesterol were produced. Foam cells also displayed a significant accumulation of free cholesterol at the plasma membrane, as measured by percent cholestenone formed. Intracellularly, there was a significant decrease in lipid droplet number and an increase in size in probucol-treated THP-1 foam cells when compared to non-treated cells. Conclusions We report for the first time that probucol is unable to completely inhibit cholesterol efflux in foam cells to the same extent as in non-foam cells. Indeed, functional nHDL is released from foam cells in the presence of probucol. This difference in inhibitory effect could potentially be explained by changes in the plasma membrane pool as well as intracellular cholesterol storage independently of ABCA1

    Enhanced performance of longitudinally post-tensioned long-span LVL beams

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    The scope of this paper is to highlight the advantages of using longitudinally post-tensioning for long-span timber beams compared to traditional glulam or LVL solutions. The analysis is limited to serviceability limit states for gravity loads. An analtycal iterative procedure which takes into account tendon elongation within beam deflecting has been implemented and validated through experimental tests carried out at the University of Canterbury.In particular, two different static configurations have been studied and different tendon profile configurations (straight and draped) internal and external to the beam section have been investigated and compared with traditional solid timber beams. The experimental results confirm the enhanced performance in terms of deflections at serviceability limit state of the longitudinally post-tensioned solutions with respect to traditional timber beams, especially if external draped tendons are adopted

    Effect of Ethyl Ester L-Lysine Triisocyanate addition to produce reactive PLA/PCL bio-polyester blends for biomedical applications

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    We report in this paper the effects of Ethyl Ester L-Lysine Triisocyanate (LTI) on the physical-mechanical properties of Poly(lactide)/Poly(ε-caprolactone) (PLA/PCL) polyesters blends. The PLA/PCL ratios considered were 20/80, 50/50 and 80/20 (wt/wt %) and LTI was added in amounts of 0.0-0.5-1.0 phr. PLA and PCL reacted with LTI during processing in a Brabender twin screw internal mixer to produce block copolymers in-situ. The resulting blends have been characterized by torque measurements, uniaxial tensile tests, Differential Scanning Calorimeter, contact angle measurements with a Phosphate Buffered Saline (PBS) solution, ATR analysis and morphological SEM observations. Experimental results highlighted how LTI enhanced interaction and dispersion of the two components, resulting into a synergic effect in mechanical properties. Mechanical and physical properties can be tailored by changing the blend composition. The most noticeable trend was an increase in ductility of the mixed polymers. Besides, LTI decreased blend’s wet ability in PBS and lowered the starting of crystalline phase formation for both polymers, confirming an interaction among them. These reactive blends could find use as biomedical materials, e.g. absorbable suture threads or scaffolds for cellular growth

    Design and synthesis of sulfonamides incorporating a biotin moiety: Carbonic anhydrase inhibitory effects, antiproliferative activity and molecular modeling studies

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    : Sulfonamides constitute an important class of classical carbonic anhydrase (CA, EC 4.2.1.1) inhibitors. Herein we have accomplished the conjugation of biotin with an ample number of sulfonamide motifs with the aim of testing them in vitro as inhibitors of the human carbonic anhydrase (hCA) isoforms I and II (cytosolic isozymes), as well as hCA IX and XII (transmembrane, tumor-associated enzymes). Most of these newly synthesized compounds exhibited interesting inhibition profiles, with activities in the nanomolar range. The presence of a 4-F-C6H4 moiety, also found in SLC-0111, afforded an excellent selectivity towards the tumor-associated hypoxia-induced hCA isoform XII with an inhibition constant (KI) of 4.5 nM. The 2-naphthyl derivative was the most potent inhibitor against hCA IX (KI = 6.2 nM), 4-fold stronger than AAZ (KI = 25 nM) with very good selectivity. Some compounds were chosen for antiproliferative activity testing against a panel of 3 human tumor cell lines, one compound showing anti-proliferative activity on glioblastoma, triple-negative breast cancer, and pancreatic carcinoma cell lines
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