517 research outputs found
LE GALLERIE METROPOLITANE COME SCAMBIATORI DI CALORE: UNA IDEA DI APPLICAZIONE A TORINO
L'attivazione termica dei rivestimenti delle gallerie urbane può consentire di sfruttare l'inerzia termica del sottosuolo al fine di riscaldare o raffrescare gli edifici in superficie. Nell'ambito di una ricerca in corso al Politecnico di Torino, la nota descrive una possibile applicazione alla metropolitana di Torino descrivendo alcuni risultati di analisi numeriche finalizzate a studiare gli effetti dell'attivazione termica del rivestimento della galleria sulla falda preesistent
Classification of Epileptic Activity Through Temporal and Spatial Characterization of Intracranial Recordings
Focal epilepsy is a chronic condition characterized by hyper-activity and abnormal synchronization of a specific brain region. For pharmacoresistant patients, the surgical resection of the critical area is considered a valid clinical solution, therefore, an accurate localization is crucial to minimize neurological damage. In current clinical routine the characterization of the Epileptogenic Zone (EZ) is performed using invasive methods, such as Stereo-ElectroEncephaloGraphy (SEEG). Medical experts perform the tag of neural electrophysiological recordings by visually inspecting the acquired data, a highly time consuming and subjective procedure. Here we show the results of an automatic multi-modal classification method for the evaluation of critical areas in focal epileptic patients. The proposed method represents an attempt in the characterization of brain areas which integrates the anatomical information on neural tissue, inferred using Magnetic Resonance Imaging (MRI) in combination with spectral features extracted from SEEG recordings
Introducing temporal correlation in rainfall and wind prediction from underwater noise
While in the past the prediction of wind and rainfall
from underwater noise was performed using empirical equations
fed with very few spectral bins and fitted to the data, it has recently
been shown that regression performed using supervised machine
learning techniques can benefit from the simultaneous use of all
spectral bins, at the cost of increased complexity. However, both
empirical equations and machine learning regressors perform the
prediction using only the acoustic information collected at the time
when one wants to know the wind speed or the rainfall intensity. At
most, averages are made between spectra measured at subsequent
times (spectral compounding) or between predictions obtained
at subsequent times (prediction compounding). In this article,
it is proposed to exploit the temporal correlation inherent in the
phenomena being predicted, as has already been done in methods
that forecast wind and rainfall from their values (and sometimes
those of other meteorological quantities) in the recent past. A
special architecture of recurrent neural networks, the long shortterm memory, is used along with a data set composed of about
16 months of underwater noise measurements (acquired every
10 min, simultaneously with wind and rain measurements above
the sea surface) to demonstrate that the introduction of temporal
correlation brings significant advantages, improving the accuracy
and reducing the problems met in the widely adopted memoryless
prediction performed by random forest regression. Working with
samples acquired at 10-min intervals, the best performance is
obtained by including three noise spectra for wind prediction and
six spectra for rainfall prediction
Pengaruh Tingkat Intensitas Pemberian Latihan Soal Terhadap Prestasi Belajar Siswa Dalam Mata Pelajaran Pkn
Exercise is an activity of repetition in the learning process that aims to motivate students to better understand the learning materials in order to obtain better results. With the provision of the exercises that the students are expected to help improve student learning outcomes especially in subjects Citizenship Education. The purpose of this study was to clarify the effect of the intensity level of giving exercises on student achievement in the subjects of Civics class VII at Junior High School 21 Bandar Lampung academic year 2012/2013. The research method used in this study is a quantitative method of testing the influence. The samples in this study were 30. Data analysis using Chi Square. The results showed that: (1) the influence of the intensity of the exercises provision (X) dominant in the category of influential with percentage 36.6%, (2) achievement (Y) dominant in the high category with the percentage of 40%, (3) the results of research shows there is a positive relationship, significant, and category tinngi closeness between the effect of the intensity level of the provision of the learning exercises, which means that the prominence of the level of intensity of exercises possible giving further improve student achievement in the subjects of Civics
Energy Tunnels for Deicing of a Bridge Deck in Alpine Region
Roads and paved surfaces in cold climate are exposed to the formation of ice and snow deposition. These phenomena are related to high risks for vehicles and road users due to reduced friction. Deicing techniques are up to now mainly based on chemicals, especially salt. These substances induce chemical decay of concrete infrastructure elements and environmental harm. In order to overcome these drawbacks, the use of embedded hydraulic pipes with a hot carrier fluid below the paved surfaces has been proposed in last decades. This circuit can be part of a Ground Source Heat Pump (GSHP) system. Despite a number of examples of this technology have been proposed, very few of them included the application of energy tunnels. This paper focuses on the thermal activation of a tunnel lining in relation to an application for bridge deck deicing. A theoretical case study along an Alpine road has been considered as representative of a common situation of alternated bridges and tunnels. The numerical results show that the thermal activation of the tunnel lining can provide enough heat to keep the paved surface unfrozen even in protracted periods of low external temperatures
Theoretical Methods for Wave Propagation across Jointed Rock Masses
Different methods are presently available for the analysis of wave propagation across jointed rock masses with the consideration of multiple wave reflections between joints. These methods can be divided into two categories. One is based on the displacement discontinuity model for representing rock joints, where the displacements across a joint are discontinuous and the tractions are continuous, and the other is the equivalent medium method. For the first category, there are three methods, i.e., method of characteristics (MC), scattering matrix method (SMM) and virtual wave source method (VWS). MC solves the equation of motion by using the theory of characteristic curves. SMM is based on the definition of the scattering matrix in which the reflection and transmission coefficients of a set of joints are stored. VWS method replaces the joints in the rock mass with a virtual concept. For the second category, equivalent medium model treats the problem in the frame of continuum mechanics and simplifies it from an explicit wave propagation equation. The objective of this paper is to review and compare these theoretical methods. The comparison shows that the four solutions agree very well with each other. Some additional considerations about the advantages and disadvantages of these methods are also given in the pape
Discontinuous Transition from a Real Bound State to Virtual Bound State in a Mixed-Valence State of SmS
Golden SmS is a paramagnetic, mixed-valence system with a pseudogap. With
increasing pressure across a critical pressure Pc, the system undergoes a
discontinuous transition into a metallic, anti-ferromagnetically ordered state.
By using a combination of thermodynamic, transport, and magnetic measurements,
we show that the pseudogap results from the formation of a local bound state
with spin singlet. We further argue that the transition Pc is regarded as a
transition from an insulating electron-hole gas to a Kondo metal, i.e., from a
spatially bound state to a Kondo virtually bound state between 4f and
conduction electrons.Comment: 5 pages, 5 figure
Protection des habitats d'espèces menacées en terres privées: analyse d'instruments et de la politique canadienne
The preservation of biodiversity requires the protection of endangered species' habitats. In Canada, approximately 60% of these habitats are located on private lands. We start by analysing the obstacles to the protection of endangered species' habitats, with special attention to the compensation of private property owners affected by conservation efforts. After briefly reviewing the main measures adopted in Canada to protect natural habitats on private lands, we propose some conservation mechanisms that would not excessively burden public budgets. These measures should be discussed in the next proposal for a Canadian endangered species act. La préservation de la biodiversité nécessite la protection des habitats des espèces menacées. Au Canada, environ 60% de ces habitats sont situés sur des terres privées. Nous examinons la problématique de protection de ces habitats et notamment la question de la compensation des propriétaires privés. Nous analysons ensuite les principales mesures utilisées au Canada pour préserver les habitats naturels, et nous proposons des mécanismes de protection qui permettraient de dédommager les propriétaires terriens affectés tout en limitant les dépenses publiques. Ces mécanismes devraient être discutés lors de la prochaine proposition de loi sur la protection des espèces menacées au Canada.Biodiversité, habitats fauniques, instruments économiques
Study of electrically active defects in epitaxial layers on silicon
Electrically active defects in silicon-based epitaxial layers on silicon substrates have been studied by Deep-Level Transient Spectroscopy (DLTS). Several aspects have been investigated, like, the impact of the pre-epi cleaning conditions and the effect of a post-deposition anneal on the deep-level properties. It is shown that the pre-cleaning thermal budget has a strong influence on the defects at the substrate/epi layer interface. At the same time, a post-deposition Forming Gas Anneal can passivate to a large extent the active defect states. Finally, it is shown that application of a post-deposition anneal increases the out-diffusion of carbon from a Si:C stressor layer into the p-type CZ substrate
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