Search results for "space-time"

Hypergestures in Complex Time: Creative Performance Between Symbolic and Physical Reality

2015

Musical performance and composition imply hypergestural transformation from symbolic to physical reality and vice versa. But most scores require movements at infinite physical speed that can only be performed approximately by trained musicians. To formally solve this divide between symbolic notation and physical realization, we introduce complex time (\(\mathbb {C}\)-time) in music. In this way, infinite physical speed is “absorbed” by a finite imaginary speed. Gestures thus comprise thought (in imaginary time) and physical realization (in real time) as a world-sheet motion in space-time, corresponding to ideas from physical string theory. Transformation from imaginary to real time gives us…

Detection and Recognition of Target Signals in Radar Clutter via Adaptive CFAR Tests

2006

In this paper, adaptive CFAR tests are described which allow one to classify radar clutter into one of several major categories, including bird, weather, and target classes. These tests do not require the arbitrary selection of priors as in the Bayesian classifier. The decision rule of the recognition techniques is in the form of associating the p-dimensional vector of observations on the object with one of the m specific classes. When there is the possibility that the object does not belong to any of the m classes, then this object is to be classified as belonging to one of the m classes or to class m+1 whose distribution is unspecified. The tests are invariant to intensity changes in the …

The zitterbewegung interpretation of quantum mechanics as theoretical framework for ultra-dense deuterium and low energy nuclear reactions

2017

This paper introduces a Zitterbewegung model of the electron by applying the principle of Occam's razor to the Maxwell's equations and by introducing a scalar component in the electromagnetic field. The aim is to explain, by using simple and intuitive concepts, the origin of the electric charge and the electromagnetic nature of mass and inertia. The Zitterbewegung model of the electron is also proposed as the best suited theoretical framework to study the structure of Ultra-Dense Deuterium (UDD), the origin of anomalous heat in metal-hydrogen systems and the possibility of existence of "super-chemical" aggregates at Compton scale.

Tempio e sinagoga. La relazione spazio-tempo nella religione ebraica

2021

the complex definition of a sacred place starting from the biblical text and from founding texts such as the Mishnah and the Talmud; sacred time in the exegetical tradition of traditional Judaism.

Spatial representations of the future in Homeric Greek

The aim of this paper is to investigate the space-time mapping of the future in Homeric Greek. It is widely accepted that the spatial adverbs πρόσσω ‘in front’ and ὀπίσσω ‘behind’ in the Homeric poems are used to portray temporal events located in a sequence of aligned entities that follow one after the other on the same path (Dunkel 1983: 66). In such a temporal sequence, or Time-RP model, those adverbs are associated respectively to past and future events in a dichotomous spatial representation of time, without involving a deictic ego-experiencer. After analyzing data from the Homeric poems in a cognitive linguistic perspective, it is found that some temporal uses of the preposition πρό ‘…

All’origine della deissi indoeuropea. Un approccio linguistico cognitivo

2020

This paper focuses on the existence of temporal deixis in Indo-European, questioning the traditional view according to which metaphors of time in ancient Indo-European languages originated from projecting the human body coordinates onto space. In particular, it aims at interpreting data from historical-comparative linguistics by using the cognitive linguistic framework, without disregarding the most recent results from typological studies, spatial language acquisition, and neurolinguistic research on spatiotemporal deixis. Contrary to what previously assumed, the comparative analysis between the Rigveda and the Homeric poems shows that earlier spatial metaphors of time are still deictically…

FLP estimation of semi-parametric models for space-time point processes and diagnostic tools

2015

Abstract The conditional intensity function of a space–time branching model is defined by the sum of two main components: the long-run term intensity and short-run term one. Their simultaneous estimation is a complex issue that usually requires the use of hard computational techniques. This paper deals with a new mixed estimation approach for a particular space–time branching model, the Epidemic Type Aftershock Sequence model. This approach uses a simultaneous estimation of the different model components, alternating a parametric step for estimating the induced component by Maximum Likelihood and a non-parametric estimation step, for the background intensity, by FLP (Forward Predictive Like…

Bayesian Markov switching models for the early detection of influenza epidemics

2008

The early detection of outbreaks of diseases is one of the most challenging objectives of epidemiological surveillance systems. In this paper, a Markov switching model is introduced to determine the epidemic and non-epidemic periods from influenza surveillance data: the process of differenced incidence rates is modelled either with a first-order autoregressive process or with a Gaussian white-noise process depending on whether the system is in an epidemic or in a non-epidemic phase. The transition between phases of the disease is modelled as a Markovian process. Bayesian inference is carried out on the former model to detect influenza epidemics at the very moment of their onset. Moreover, t…

Including covariates in a space-time point process with application to seismicity

2020

AbstractThe paper proposes a spatio-temporal process that improves the assessment of events in space and time, considering a contagion model (branching process) within a regression-like framework to take covariates into account. The proposed approach develops the forward likelihood for prediction method for estimating the ETAS model, including covariates in the model specification of the epidemic component. A simulation study is carried out for analysing the misspecification model effect under several scenarios. Also an application to the Italian seismic catalogue is reported, together with the reference to the developed R package.

Windowed Etas Models With Application To The Chilean Seismic Catalogs

2015

Abstract The seismicity in Chile is estimated using an ETAS (Epidemic Type Aftershock sequences) space–time point process through a semi-parametric technique to account for the estimation of parametric and nonparametric components simultaneously. The two components account for triggered and background seismicity respectively, and are estimated by alternating a ML estimation for the parametric part and a forward predictive likelihood technique for the nonparametric one. Given the geographic and seismological characteristics of Chile, the sensitivity of the technique with respect to different geographical areas is examined in overlapping successive windows with varying latitude. A different b…