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1.
Sci Total Environ ; 700: 134415, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31629265

RESUMO

Bioclimatic indices combine atmospheric parameters to provide analytical indication of climatic features and their evolution in space and time that can directly relate with natural resource availability, distribution, and related bio-physical processes. The availability of bioclimatic information can provide natural resource managers with analytical means to assess the magnitude and temporal evolution of drought and climate change parameters that could affect the availability, demand and use of natural resources for various sectors. This paper presents a methodology to process bioclimatic data in the space and time domains for assessing the moisture/dryness level and water requirements of a region, and inform water resource planning and management decisions related to drought, climate variability and change. The methodology relies on a modular assembly of statistical tests and methods, and utilizes point scale measurements of meteorological data to perform the analysis of the spatial behavior of derived bioclimatic indicators at the continuous regional scale, and evaluate the significance of the temporal trends. Also, the article presents an application of the proposed methodology to a coastal area of southern Italy (the Apulia Region) that is characterized by recurring water supply limitations, involving the use of the popular De Martonne bioclimatic aridity index. The methodology allowed to obtain qualitative and quantitative information about the aridity level of the Apulia region, the identification of main bioclimatic zones, and the evaluation of spatial pattern and time evolution of aridity. The determination of bioclimatic zones showed that nearly 40% of the regional territory is characterized by dry sub-humid (Mediterranean) climate, about 30% by sub-humid climate, while nearly 10% and 20% are characterized by semi-arid and humid climates, respectively. The temporal analysis revealed that the Salento and the Ionian coastal zone are areas at risk of increasing aridity, with resulting impacts on the water supply and demand for irrigated agriculture.


Assuntos
Monitoramento Ambiental , Mudança Climática , Secas , Ecossistema , Itália , Conceitos Meteorológicos , Estações do Ano , Abastecimento de Água
2.
Sensors (Basel) ; 19(6)2019 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-30889879

RESUMO

A built environment, that also includes infrastructures, needs to be taken under control to prevent unexpected modifications, otherwise it could react as a loose cannon. Sensing techniques and technologies can come to the rescue of built environments thanks to their capabilities to monitor appropriately. This article illustrates findings related to monitoring a channel hydrodynamic behavior by means of sensors based on imaging and ultrasound. The ultrasound approach is used here to monitor the height of the water with respect to a maximum limit. Imaging treatment is here proposed to understand the flow velocity under the area to be considered. Since these areas can be covered by trash, an enhanced version of the particle image velocimetry technique has been implemented, allowing the discrimination of trash from water flow. Even in the presence of the total area occupied by trash, it is able to detect the velocity of particles underneath. Rainfall and hydraulic levels have been included and processed to strengthen the study.

3.
Rev Sci Instrum ; 89(8): 084301, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30184631

RESUMO

Multimodal medical image sensor fusion has revolutionized the medical analysis by improving the precision of computer assisted diagnosis. This is incorporated by highlighting the complementary information while minimizing the redundant content in the fused images from various biomedical sensors like MRI, Computed Tomography, and Positron Emission Tomography/Single-Photon Emission Computerized Tomography. Multispectral image fusion is a special case of multimodal fusion which serves to encompass both spatial and spectral details in the fused image. This paper presents a hybrid sub-band decomposition scheme for multispectral image fusion comprising of non-subsampled contourlet transform and shearlet transform domains. The pre-processing stage involves color transformation of an input multispectral image from red-green-blue to YIQ color space. Thereafter, both the source images (i.e., panchromatic and multispectral images) after sub-band decomposition are processed via the application of contrast enhancement, weighted-principal component analysis, and max-max algorithms. The low frequency coefficients are processed via phase congruency whereas a combination of directive contrast and normalized Shannon entropy is applied to high frequency coefficients. The objective assessment of image quality has been carried out using various reference and no-reference based performance metrics. The distinguishing fusion response of the proposed hybrid scheme has been validated by the comparisons done with the other fusion approaches.


Assuntos
Diagnóstico por Imagem , Processamento de Imagem Assistida por Computador/métodos , Cor
4.
Sensors (Basel) ; 18(6)2018 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-29867021

RESUMO

Pipelines conveying fluids are considered strategic infrastructures to be protected and maintained. They generally serve for transportation of important fluids such as drinkable water, waste water, oil, gas, chemicals, etc. Monitoring and continuous testing, especially on-line, are necessary to assess the condition of pipelines. The paper presents findings related to a comparison between two spectral response algorithms based on the decimated signal diagonalization (DSD) and decimated Padé approximant (DPA) techniques that allow to one to process signals delivered by pressure sensors mounted on an experimental pipeline.

5.
Rev Sci Instrum ; 87(7): 074303, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27475574

RESUMO

Computer based diagnosis of Alzheimer's disease can be performed by dint of the analysis of the functional and structural changes in the brain. Multispectral image fusion deliberates upon fusion of the complementary information while discarding the surplus information to achieve a solitary image which encloses both spatial and spectral details. This paper presents a Non-Sub-sampled Contourlet Transform (NSCT) based multispectral image fusion model for computer-aided diagnosis of Alzheimer's disease. The proposed fusion methodology involves color transformation of the input multispectral image. The multispectral image in YIQ color space is decomposed using NSCT followed by dimensionality reduction using modified Principal Component Analysis algorithm on the low frequency coefficients. Further, the high frequency coefficients are enhanced using non-linear enhancement function. Two different fusion rules are then applied to the low-pass and high-pass sub-bands: Phase congruency is applied to low frequency coefficients and a combination of directive contrast and normalized Shannon entropy is applied to high frequency coefficients. The superiority of the fusion response is depicted by the comparisons made with the other state-of-the-art fusion approaches (in terms of various fusion metrics).


Assuntos
Doença de Alzheimer/diagnóstico por imagem , Encéfalo/diagnóstico por imagem , Diagnóstico por Computador/métodos , Tomografia por Emissão de Pósitrons , Tomografia Computadorizada com Tomografia Computadorizada de Emissão de Fóton Único , Humanos , Processamento de Imagem Assistida por Computador
6.
Appl Bionics Biomech ; 2015: 798748, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-27019593

RESUMO

Background. Tactile interfaces that stimulate the plantar surface with vibrations could represent a step forward toward the development of wearable, inconspicuous, unobtrusive, and inexpensive assistive devices for people with visual impairments. Objective. To study how people understand information through their feet and to maximize the capabilities of tactile-foot perception for assisting human navigation. Methods. Based on the physiology of the plantar surface, three prototypes of electronic tactile interfaces for the foot have been developed. With important technological improvements between them, all three prototypes essentially consist of a set of vibrating actuators embedded in a foam shoe-insole. Perceptual experiments involving direction recognition and real-time navigation in space were conducted with a total of 60 voluntary subjects. Results. The developed prototypes demonstrated that they are capable of transmitting tactile information that is easy and fast to understand. Average direction recognition rates were 76%, 88.3%, and 94.2% for subjects wearing the first, second, and third prototype, respectively. Exhibiting significant advances in tactile-foot stimulation, the third prototype was evaluated in navigation tasks. Results show that subjects were capable of following directional instructions useful for navigating spaces. Conclusion. Footwear providing tactile stimulation can be considered for assisting the navigation of people with visual impairments.

7.
Int J Neural Syst ; 22(6): 1250024, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23186273

RESUMO

Epileptic seizures are thought to be generated and to evolve through an underlying anomaly of synchronization in the activity of groups of neuronal populations. The related dynamic scenario of state transitions is revealed by detecting changes in the dynamical properties of Electroencephalography (EEG) signals. The recruitment procedure ending with the crisis can be explored through a spatial-temporal plot from which to extract suitable descriptors that are able to monitor and quantify the evolving synchronization level from the EEG tracings. In this paper, a spatial-temporal analysis of EEG recordings based on the concept of permutation entropy (PE) is proposed. The performance of PE are tested on a database of 24 patients affected by absence (generalized) seizures. The results achieved are compared to the dynamical behavior of the EEG of 40 healthy subjects. Being PE a feature which is dependent on two parameters, an extensive study of the sensitivity of the performance of PE with respect to the parameters' setting was carried out on scalp EEG. Once the optimal PE configuration was determined, its ability to detect the different brain states was evaluated. According to the results here presented, it seems that the widely accepted model of "jump" transition to absence seizure should be in some cases coupled (or substituted) by a gradual transition model characteristic of self-organizing networks. Indeed, it appears that the transition to the epileptic status is heralded before the preictal state, ever since the interictal stages. As a matter of fact, within the limits of the analyzed database, the frontal-temporal scalp areas appear constantly associated to PE levels higher compared to the remaining electrodes, whereas the parieto-occipital areas appear associated to lower PE values. The EEG of healthy subjects neither shows any similar dynamic behavior nor exhibits any recurrent portrait in PE topography.


Assuntos
Ondas Encefálicas/fisiologia , Sincronização de Fases em Eletroencefalografia/fisiologia , Eletroencefalografia/estatística & dados numéricos , Epilepsia Tipo Ausência/fisiopatologia , Dinâmica não Linear , Adolescente , Estudos de Casos e Controles , Criança , Eletroencefalografia/métodos , Entropia , Feminino , Humanos , Masculino
8.
Artigo em Inglês | MEDLINE | ID: mdl-21598127

RESUMO

Pulmonary oedema is a life-threatening disease that requires special attention in the area of research and clinical diagnosis. Computer-based techniques are rarely used to quantify the intrathoracic fluid volume (IFV) for diagnostic purposes. This paper discusses a software program developed to detect and diagnose pulmonary oedema using LabVIEW. The software runs on anthropometric dimensions and physiological parameters, mainly transthoracic electrical impedance (TEI). This technique is accurate and faster than existing manual techniques. The LabVIEW software was used to compute the parameters required to quantify IFV. An equation relating per cent control and IFV was obtained. The results of predicted TEI and measured TEI were compared with previously reported data to validate the developed program. It was found that the predicted values of TEI obtained from the computer-based technique were much closer to the measured values of TEI. Six new subjects were enrolled to measure and predict transthoracic impedance and hence to quantify IFV. A similar difference was also observed in the measured and predicted values of TEI for the new subjects.


Assuntos
Cardiografia de Impedância/métodos , Diagnóstico por Computador/métodos , Água Extravascular Pulmonar/química , Modelos Biológicos , Edema Pulmonar/diagnóstico , Edema Pulmonar/fisiopatologia , Software , Simulação por Computador , Humanos , Linguagens de Programação , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
9.
Artigo em Inglês | MEDLINE | ID: mdl-21989874

RESUMO

Current imaging methods for catheter position monitoring during minimally invasive surgery do not provide an effective support to surgeons, often resulting in the choice of more invasive procedures. This study was conducted to demonstrate the feasibility of non-ionizing monitoring of endovascular devices through embedded quantitative ultrasound (QUS) methods, providing catheter self-localization with respect to selected anatomical structures. QUS-based algorithms for real-time automatic tracking of device position were developed and validated on in vitro and ex vivo phantoms. A trans-esophageal ultrasound probe was adapted to simulate an endovascular device equipped with an intravascular ultrasound probe. B-mode images were acquired and processed in real time by means of a new algorithm for accurate measurement of device position. After off-line verification, automatic position calculation was found to be correct in 96% and 94% of computed frames in the in vitro and ex vivo phantoms, respectively. The average errors of distance measurements (bias ± 2SD) in a 41-step 10-cm-long parabolic pathway were 0.76 ± 3.75 mm or 0.52 ± 3.20 mm, depending on algorithm implementations. Our results showed the effectiveness of QUS-based tracking algorithms for real-time automatic calculation and display of endovascular system position. The method, validated for the case of an endoclamp balloon catheter, can be easily extended to most endovascular surgical systems.


Assuntos
Cateterismo/métodos , Processamento de Imagem Assistida por Computador/métodos , Cirurgia Assistida por Computador/métodos , Ultrassonografia de Intervenção/métodos , Algoritmos , Animais , Aorta Torácica/diagnóstico por imagem , Cateterismo/instrumentação , Bovinos , Imagens de Fantasmas , Reprodutibilidade dos Testes , Cirurgia Assistida por Computador/instrumentação , Ultrassonografia de Intervenção/instrumentação
10.
Conf Proc IEEE Eng Med Biol Soc ; 2008: 2310-3, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-19163163

RESUMO

There is an increasing demand for giving energetic autonomy to portable and autonomous biomedical devices used not only by patients but common people who need to use the aforementioned devices. For instance, hearing aids, in order to be used for long time, must be connected to re-chargeable batteries in order to help people in case of lack of permanent electric sources. In particular, for audio-prosthesis, it is very interesting to extract electric energy from temperature or articulation movements. This paper presents some criteria of designing a conditioning and re-charging unit in order to convert human basal warmth to electric energy for audio-prosthesis; the system is based on PIC microcontroller that allows the managing of two temperatures: internal and external.


Assuntos
Fontes de Energia Bioelétrica , Auxiliares de Audição , Algoritmos , Temperatura Corporal , Desenho de Equipamento , Humanos , Software
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