On Expressing and Monitoring Oscillatory Dynamics

To express temporal properties of dense-time real-valued signals, the Signal Temporal Logic (STL) has been defined by Maler et al. The work presented a monitoring algorithm deciding the satisfiability of STL formulae on finite discrete samples of continuous signals. The logic has been used to express and analyse biological systems, but it is not expressive enough to sufficiently distinguish oscillatory properties important in biology. In this paper we define the extended logic STL* in which STL is augmented with a signal-value freezing operator allowing us to express (and distinguish) detailed properties of biological oscillations. The logic is supported by a monitoring algorithm prototyped in Matlab. The monitoring procedure of STL* is evaluated on a biologically-relevant case study.Comment: In Proceedings HSB 2012, arXiv:1208.315

A Rewriting-Logic-Based Technique for Modeling Thermal Systems

This paper presents a rewriting-logic-based modeling and analysis technique for physical systems, with focus on thermal systems. The contributions of this paper can be summarized as follows: (i) providing a framework for modeling and executing physical systems, where both the physical components and their physical interactions are treated as first-class citizens; (ii) showing how heat transfer problems in thermal systems can be modeled in Real-Time Maude; (iii) giving the implementation in Real-Time Maude of a basic numerical technique for executing continuous behaviors in object-oriented hybrid systems; and (iv) illustrating these techniques with a set of incremental case studies using realistic physical parameters, with examples of simulation and model checking analyses.Comment: In Proceedings RTRTS 2010, arXiv:1009.398

Real-time and Probabilistic Temporal Logics: An Overview

Over the last two decades, there has been an extensive study on logical formalisms for specifying and verifying real-time systems. Temporal logics have been an important research subject within this direction. Although numerous logics have been introduced for the formal specification of real-time and complex systems, an up to date comprehensive analysis of these logics does not exist in the literature. In this paper we analyse real-time and probabilistic temporal logics which have been widely used in this field. We extrapolate the notions of decidability, axiomatizability, expressiveness, model checking, etc. for each logic analysed. We also provide a comparison of features of the temporal logics discussed

On the Expressiveness of Languages for Complex Event Recognition

Complex Event Recognition (CER for short) has recently gained attention as a mechanism for detecting patterns in streams of continuously arriving event data. Numerous CER systems and languages have been proposed in the literature, commonly based on combining operations from regular expressions (sequencing, iteration, and disjunction) and relational algebra (e.g., joins and filters). While these languages are naturally first-order, meaning that variables can only bind single elements, they also provide capabilities for filtering sets of events that occur inside iterative patterns; for example requiring sequences of numbers to be increasing. Unfortunately, these type of filters usually present ad-hoc syntax and under-defined semantics, precisely because variables cannot bind sets of events. As a result, CER languages that provide filtering of sequences commonly lack rigorous semantics and their expressive power is not understood. In this paper we embark on two tasks: First, to define a denotational semantics for CER that naturally allows to bind and filter sets of events; and second, to compare the expressive power of this semantics with that of CER languages that only allow for binding single events. Concretely, we introduce Set-Oriented Complex Event Logic (SO-CEL for short), a variation of the CER language introduced in [Grez et al., 2019] in which all variables bind to sets of matched events. We then compare SO-CEL with CEL, the CER language of [Grez et al., 2019] where variables bind single events. We show that they are equivalent in expressive power when restricted to unary predicates but, surprisingly, incomparable in general. Nevertheless, we show that if we restrict to sets of binary predicates, then SO-CEL is strictly more expressive than CEL. To get a better understanding of the expressive power, computational capabilities, and limitations of SO-CEL, we also investigate the relationship between SO-CEL and Complex Event Automata (CEA), a natural computational model for CER languages. We define a property on CEA called the *-property and show that, under unary predicates, SO-CEL captures precisely the subclass of CEA that satisfy this property. Finally, we identify the operations that SO-CEL is lacking to characterize CEA and introduce a natural extension of the language that captures the complete class of CEA under unary predicates

Design, Commissioning and Performance of the PIBETA Detector at PSI

We describe the design, construction and performance of the PIBETA detector built for the precise measurement of the branching ratio of pion beta decay, pi+ -> pi0 e+ nu, at the Paul Scherrer Institute. The central part of the detector is a 240-module spherical pure CsI calorimeter covering 3*pi sr solid angle. The calorimeter is supplemented with an active collimator/beam degrader system, an active segmented plastic target, a pair of low-mass cylindrical wire chambers and a 20-element cylindrical plastic scintillator hodoscope. The whole detector system is housed inside a temperature-controlled lead brick enclosure which in turn is lined with cosmic muon plastic veto counters. Commissioning and calibration data were taken during two three-month beam periods in 1999/2000 with pi+ stopping rates between 1.3*E3 pi+/s and 1.3*E6 pi+/s. We examine the timing, energy and angular detector resolution for photons, positrons and protons in the energy range of 5-150 MeV, as well as the response of the detector to cosmic muons. We illustrate the detector signatures for the assorted rare pion and muon decays and their associated backgrounds.Comment: 117 pages, 48 Postscript figures, 5 tables, Elsevier LaTeX, submitted to Nucl. Instrum. Meth.

Palaeo-Philosophy: Archaic Ideas about Space and Time

This paper argues that efforts to understand historically remote patterns of thought are driven away from their original meaning if the investigation focuses on reconstruction of concepts, instead of cognitive complexes. My paper draws on research by Jan Assmann, Jean-Jacques Glassner, Keimpe Algra, Alex Purves, Nicholas Wyatt, and others on the cultures of Ancient Greece, Israel, Egypt, Mesopotamia, and Etruria through comparative analyses of the semantic fields of spatial and temporal terms, and how these terms are shaped by their relation to the sphere of the sacred. It shows that there are three super-ordinate timeframes - the cyclical, the linear and the static - each of which is composed of lower-order cycles (days, lunar months, and seasons). These timeframes reflect their cultures ideas about the nature, scope and power of the gods, and structure the common point-of-view about the present, the past and eternity. There are also super-ordinate spatial frames which reflect their cultures ideas about the heavens and which structure both the sacred precinct and the profane field of action and exchange. Close analysis of texts that use words such as eternity, forever, past, present, and future, for example, do not reveal that there is anything like a general abstract concept of time in virtue of which some thing or event can be said to be in time or to have its own time. Archaic patterns of thought do not differ from our modern patterns in having different concepts, but in not having anything like concepts at all

A linear temporal logic model checking method over finite words with correlated transition attributes

Temporal logic model checking techniques are applied, in a natural way, to the analysis of the set of finite traces composing a system log. The specific nature of such traces helps in adapting traditional techniques in order to extend their analysis capabilities. The paper presents an adaption of the classical Timed Propositional Temporal Logic to the case of finite words and considers relations among different attributes corresponding to different events. The introduced approach allows the use of general relations between event attributes by means of freeze quantifiers as well as future and past temporal operators. The paper also presents a decision procedure, as well as a study of its computational complexity

Torwards Infinite-State Verification and Planning with Linear Temporal Logic Modulo Theories

In this extended abstract, we discuss about Linear Temporal Logic Modulo Theories over finite traces (LTLMTf ), a temporal logic that we recently introduced with the goal of providing an equilibrium between generality of the formalism and decidability of the logic. After recalling its distinguishing features, we discuss some future applications. 2012 ACM Subject Classification Theory of computation → Logic and verificatio

Vertical structure and kinematics of tropical monsoon precipitation observed from a 2875-MHz profiler during NAME

Fall 2006.Includes bibliographical references (pages 100-105).Deep cloud systems in the Tropics play a significant role in the global heat budget. This is due to the fact that atmospheric circulations, such as the Hadley and Walker cells, are sensitive to the shape of the diabatic heating profile, which in turn depends on the vertical structure of tropical convective systems. The goal of this project is to create a climatology of the vertical structure of precipitating cloud systems that characterized the 2004 North American monsoon. The study utilized data from the 2875-MHz profiler stationed near Sinaloa, Mexico from early July through mid-September of 2004 for the North American Monsoon Experiment (NAME). The profiler observed 23 rain events. Climatologic frequency distributions of reflectivity, Doppler velocity, and spectral width were created for various precipitation regimes. The NAME distributions compared favorably with results from previous studies. Stratiform precipitation exhibited a radar bright band and a strong Doppler velocity gradient in the melting layer, and weak spectral width above the melting layer. Mixed stratiform/convective regions contained low reflectivity and a weak bright band. Convective profiles contained high reflectivity, large Doppler velocities, and high spectral width. Vertical air motions derived from the 2875-MHz profiler were compared with EVAD and 449-MHz profiler retrievals. The 2875-MHz pro filer vertical air motion estimates contained a negative bias to both methods of approximately 0.5 m s-1. Though the errors in the stratiform vertical air motion estimates were of the same order as the stratiform air motions, the NAME vertical air motion composites for stratiform and mixed stratiform/convective precipitation exhibited similar features to composites from previous studies. However, convective composites from past studies showed ascent throughout the troposphere while the NAME composite showed a significant region of descent between 4 and 6 km. This discrepancy cannot be fully explained by the negative bias of 0.5 m s-1 in the NAME estimates. Climatologic vertical profiles of precipitating clouds were successfully created from the 2875-MHz pro filer NAME dataset for various precipitation regimes. While the vertical air motion estimates yielded unexpected values in the melting layer of convective precipitation, they proved useful in analyzing the vertical structure of vertical air motion for various precipitation regimes in a mean sense as well as assessing general updraft and downdraft intensity in individual convective cells