5,887 research outputs found
A Probabilistic Linear Genetic Programming with Stochastic Context-Free Grammar for solving Symbolic Regression problems
Traditional Linear Genetic Programming (LGP) algorithms are based only on the
selection mechanism to guide the search. Genetic operators combine or mutate
random portions of the individuals, without knowing if the result will lead to
a fitter individual. Probabilistic Model Building Genetic Programming (PMB-GP)
methods were proposed to overcome this issue through a probability model that
captures the structure of the fit individuals and use it to sample new
individuals. This work proposes the use of LGP with a Stochastic Context-Free
Grammar (SCFG), that has a probability distribution that is updated according
to selected individuals. We proposed a method for adapting the grammar into the
linear representation of LGP. Tests performed with the proposed probabilistic
method, and with two hybrid approaches, on several symbolic regression
benchmark problems show that the results are statistically better than the
obtained by the traditional LGP.Comment: Genetic and Evolutionary Computation Conference (GECCO) 2017, Berlin,
German
A robust method for measurement of fluctuation parallel wavenumber in laboratory plasmas
Measuring the parallel wavenumber is fundamental for the experimental characterization of electrostatic instabilities. It becomes particularly important in toroidal geometry, where spatial inhomogeneities and curvature can excite both drift instabilities, whose wavenumber parallel to the magnetic field is finite, and interchange instabilities, which typically have vanishing parallel wavenumber. We demonstrate that multipoint measurements can provide a robust method for the discrimination between the two cases
Study of the spectral properties of ELM precursors by means of wavelets
The high confinement regime (H-mode) in tokamaks is accompanied by the occurrence of bursts of MHD activity at the plasma edge, so-called edge localized modes (ELMs), lasting less than 1 ms. These modes are often preceded by coherent oscillations in the magnetic field, the ELM precursors, whose mode numbers along the toroidal and the poloidal directions can be measured from the phase shift between Mirnov pickup coils. When the ELM precursors have a lifetime shorter than a few milliseconds, their toroidal mode number and their nonlinear evolution before the ELM crash cannot be studied reliably with standard techniques based on Fourier analysis, since averaging in time is implicit in the computation of the Fourier coefficients. This work demonstrates significant advantages in studying spectral features of the short-lived ELM precursors by using Morlet wavelets. It is shown that the wavelet analysis is suitable for the identification of the toroidal mode numbers of ELM precursors with the shortest lifetime, as well as for studying their nonlinear evolution with a time resolution comparable to the acquisition rate of the Mirnov coils
Quasimodes of a chaotic elastic cavity with increasing local losses
We report non-invasive measurements of the complex field of elastic
quasimodes of a silicon wafer with chaotic shape. The amplitude and phase
spatial distribution of the flexural modes are directly obtained by Fourier
transform of time measurements. We investigate the crossover from real mode to
complex-valued quasimode, when absorption is progressively increased on one
edge of the wafer. The complexness parameter, which characterizes the degree to
which a resonance state is complex-valued, is measured for non-overlapping
resonances and is found to be proportional to the non-homogeneous contribution
to the line broadening of the resonance. A simple two-level model based on the
effective Hamiltonian formalism supports our experimental results
THE MAIN CHARACTER’S SURVIVAL INSTINCT IN HERBERT GEORGE WELL’S NOVEL THE WAR OF THE WORLDS
One of the most interesting aspects of The War of the Worlds is the way in which the Martians are described, and the manner with which they take over the world. The aims of the study were to reveal the survival instinct of the main character in the novel “The War of The Worlds” of Herbert George Wells’s work, and how changes in behavior and the main character was currently in a state of urgency to survive. This study employed qualitative descriptive study with psychoanalytical approach initiated by Sigmund Freud, focused on literature as a reflection of real life. This research data were collected from the novel “The War of The Worlds” (1898). The study revealed that survival instinct of the main character of novel came from basic instincts, life instinct (Eros) and death instinct (Thanatos) according to Sigmund Freud’s theory. The Martians described as aliens invaded earth much more sophisticated than human, which made the main character who just a civil society striving to stay alive. The Martians had only one purpose, to destroy all humans and take over the planet. During The Martians invasion, the main character was not only trying to survive but also strived for source of food and water. In his effort to stay alive, the main character in the novel The War of The Worlds (1898) had to kill others to guarantee he stayed alive. Being trapped in regret and despair, he decided to end his own life, but something strange happened to The Martians, they were killed by bacteria. Human were immune to the bacteria, but The Martians from Mars were not and eventually died
Football intermediaries and self‑regulation: the need for greater transparency through disciplinary law, sanctioning and qualifying criteria
This paper was first presented at the International Sports Law Conference in The Hague in October 2018. It summarises the author’s work and wider research on the introduction of new proposals for the regulation of football intermediaries (a term which the author finds unworkable and unorthodox). The author’s research critically analyses the current regulatory framework and identifies the elements that form the basis for the inadequacy and ineffectiveness of the regulations currently in force. With the use of case studies and examples drawn from the author’s private practice, recommendations are produced for new regulations that would promote transparency, equality and consistency. The author concludes that this can only be achieved via a blending of self-regulation and external regulation at an international setting
Neural correlates of visuospatial working memory in the ‘at-risk mental state’
Background. Impaired spatial working memory (SWM) is a robust feature of schizophrenia and has been linked to
the risk of developing psychosis in people with an at-risk mental state (ARMS). We used functional magnetic
resonance imaging (fMRI) to examine the neural substrate of SWM in the ARMS and in patients who had just
developed schizophrenia.
Method. fMRI was used to study 17 patients with an ARMS, 10 patients with a first episode of psychosis and 15 agematched
healthy comparison subjects. The blood oxygen level-dependent (BOLD) response was measured while
subjects performed an object–location paired-associate memory task, with experimental manipulation of mnemonic
load.
Results. In all groups, increasing mnemonic load was associated with activation in the medial frontal and medial
posterior parietal cortex. Significant between-group differences in activation were evident in a cluster spanning the
medial frontal cortex and right precuneus, with the ARMS groups showing less activation than controls but greater
activation than first-episode psychosis (FEP) patients. These group differences were more evident at the most
demanding levels of the task than at the easy level. In all groups, task performance improved with repetition of the
conditions. However, there was a significant group difference in the response of the right precuneus across repeated
trials, with an attenuation of activation in controls but increased activation in FEP and little change in the ARMS.
Conclusions. Abnormal neural activity in the medial frontal cortex and posterior parietal cortex during an SWM task
may be a neural correlate of increased vulnerability to psychosis
Perkawinan Usia Dini Perempuan Korowai di Kampung Kabuage Distrik Firiwage Kabupaten Boven Digoel
This study aims to determine the form of early marriage among Korowai women and want to know the factors that influence the occurrence of early marriage for Korowai women in Kabuage village, Firiwage district, Boven Digoel district. The research method used is descriptive-qualitative method, because this method is considered capable of analyzing social reality in detail. Research informants include women who marry early, traditional parents, men and the village head. Data collection was carried out using literature study and field study techniques which included observation, interviews and literature studies. In analyzing the data, three lines of interactive analysis were used, namely data reduction, data presentation and conclusion drawing. The results showed that there were two forms of early marriage in women, namely the form of coercion and without coercion and the driving factors for early marriage in women in Kabuage Village were cultural, educational, economic and modernization factors. The conclusions and suggestions of this study are that early marriage among Korowai women in Kabuage Village, Firiwage District, Boven Digoel Regency occurs in the form of coercion and without coercion which generally occurs due to cultural, educational, economic and modernization factors. Then the suggestion that can be given is the need for the involvement of the Office of Women Empowerment and Family Planning (KB) in Boven Digoel Regency to suppress marriage at an early age. So, it can provide a good understanding to parents, community and traditional leaders. As well as creating more opportunities for girls to obtain rights in accordance with the Rights of the Child Convention. As well as the need for the efforts of various agencies to work together to help human resources in Kabuage Village
USE OF HISTORICAL AERIAL IMAGES FOR 3D MODELLING OF GLACIERS IN THE PROVINCE OF TRENTO
Abstract. Historical aerial images represent a source of information of great value for glacier monitoring, as they cover the area of interest at a well-defined epoch and allow for visual interpretation and metric analysis. Typically, the aerial images are used to produce orthophotos and manually digitize the perimeters of the glaciers for analysis of the surface extent of the glaciers, while the extraction of height information is more challenging due to data quality and characteristics. This article discusses the potential of historical aerial images for glacier modelling. More specifically, it analyses the impact of their coverage, radiometric- and geometric accuracy, state of preservation and completeness on the photogrammetric workflow. The data set used consists of scans of 300 (analog) aerial images acquired between August and October 1954 by the U.S. Air Force with a Fairchild KF7660 camera over the entire Province of Trento. For the modelling of the glaciers, different techniques such as manual stereoscopic measurement and dense image matching were tested on sample glaciers and the results were analysed in detail. Due to local radiometric saturation in a large part of the glacial surfaces and other disturbances affecting the historical images (e.g. scratches, scanning errors, dark shadows), dense image matching did not produce any valuable results, and stereo plotting could be used only on images (or image parts) with acceptable quality. The derived Digital Terrain Models (DTMs) were compared with a reference DTM obtained with dense image matching from digital aerial images acquired in September 2015 with an UltraCam Eagle sensor, and, for some glaciers, to a DTM obtained with dense image matching from scanned aerial images acquired in September 1983 with a RC30 analog camera. The differences between 1954 and 2015 DTMs showed values up to 70–80 m in height and a behaviour that is confirmed by the models employed by the glaciology experts in Trento
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