207 research outputs found

    Reducing Object Detection Uncertainty from RGB and Thermal Data for UAV Outdoor Surveillance

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    Recent advances in Unmanned Aerial Vehicles (UAVs) have resulted in their quick adoption for wide a range of civilian applications, including precision agriculture, biosecurity, disaster monitoring and surveillance. UAVs offer low-cost platforms with flexible hardware configurations, as well as an increasing number of autonomous capabilities, including take-off, landing, object tracking and obstacle avoidance. However, little attention has been paid to how UAVs deal with object detection uncertainties caused by false readings from vision-based detectors, data noise, vibrations, and occlusion. In most situations, the relevance and understanding of these detections are delegated to human operators, as many UAVs have limited cognition power to interact autonomously with the environment. This paper presents a framework for autonomous navigation under uncertainty in outdoor scenarios for small UAVs using a probabilistic-based motion planner. The framework is evaluated with real flight tests using a sub 2 kg quadrotor UAV and illustrated in victim finding Search and Rescue (SAR) case study in a forest/bushland. The navigation problem is modelled using a Partially Observable Markov Decision Process (POMDP), and solved in real time onboard the small UAV using Augmented Belief Trees (ABT) and the TAPIR toolkit. Results from experiments using colour and thermal imagery show that the proposed motion planner provides accurate victim localisation coordinates, as the UAV has the flexibility to interact with the environment and obtain clearer visualisations of any potential victims compared to the baseline motion planner. Incorporating this system allows optimised UAV surveillance operations by diminishing false positive readings from vision-based object detectors

    Participatory Budgeting in the Municipality of Santo André, Brazil: The challenges in linking short-term action and long-term strategic planning

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    This report is addressed to professionals and urban practitioners who are interested in participatory planning processes and in the establishment of organised priority setting mechanisms and decision-making involving government and communities on the allocation of public investments. Those who work in the public sector or with public policies at the local government level will benefit from the findings of the research particularly if their interest lies on the establishment of government-community management of public funds. The findings of the research will be instrumental for NGO’s and CBO’s that are engaged in partnerships with local governments. The primary objective of the research is to analyse and describe the experience of the municipality of Santo André with participatory budgeting hereinafter called OP ( Orçamento Participativo) depicted from interviews and observations of key actors and stakeholders directly involved in the OP, and from the analysis of internal documents of the municipality. The research also makes a first attempt to unveil issues underlying the integration of the participatory budgeting (OP) as a short-term planning activity and the recently started strategic planning process hereinafter called CF (Cidade Futuro) as a long-term development planning process. The research makes use of participants’ observations and qualitative methods and intends not only to analyse and describe in detail the OP and CF in Santo André but also questions to what extent this peculiar participatory process can be replicated in other municipalities seeking direct citizen involvement in municipal affairs. The authors attempt to look at the lessons learned from these experiences in order to depict issues, processes and methodologies that can be replicated in Bolivian municipalities and particularly in Santa Cruz de la Sierra. The authors look at this possibility against the enactment of legislation (Law of Popular Participation, Law on Municipalities, Sustainable Municipal Development Plan-SMDP) that seems to have created a conducive environment for genuine civil participation in urban management in Bolivian local governments. The Spanish report pays a particular attention to this dimension

    Factores de riesgo/protección y prevalencias del consumo de sustancias psicoactivas en adolescentes de enseñanza media del “ I n s t i t u t o N a c i o n a l d e O c c i d e n t e ” L e ó n , J u n i o - m a y o .

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    La investigación se centró en determinar edad de inicio, factores de riesgo/protección, prevalencia e incidencia del consumo de sustancias psicoactivas lícitas e ilícitas.  Se utilizó la metodología de la CICAD-OEA-SIDUC (sistema de vigilancia contra las drogas en el hemisferio) empleada en estudios nacionales, de Latinoamérica y el Caribe.   La presente tesis contiene un enfoque clínico epidemiológico en la salud pública basada en un estudio descriptivo de corte transversal con una población constituida por 1,116 estudiantes adolescentes y una muestra representativa de 286 escolares de ambos sexos, se aplicó el cuestionario estandarizado SIDUC con indicadores predeterminados para medir tasas de prevalencia y patrones de consumo.Resultados y conclusiones evidencian que entre las drogas licitas el alcohol posee las mayores prevalencias entre los estudiantes: consumo experimental 45.5%, reciente 28.3% y actual 19.9%, seguido por el tabaco, entre las drogas ilícitas la mariguana posee las mayores prevalencias: consumo experimental 13.6%, reciente 6.3% y actual 2.8%, seguida por la cocaína.    Las prevalencias indican mayores porcentajes de consumo entre los varones, la jornada vespertina, el décimo grado y las edades entre 15-17 años. Son factores de riesgo la calle y eventos sociales, las edades de inicio cada vez más tempranas, con una edad media de 11.6 años y el entorno de pares. Son factores protectores de los estudiantes las expectativas futuras positivas y la percepción de “gran riesgo” hacia el consumo de drogas

    Factores de riesgo/protección y prevalencias del consumo de sustancias psicoactivas en adolescentes de enseñanza media del “Instituto Nacional de Occidente” León, Junio-mayo

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    DOI: http://dx.doi.org/10.5377/universitas.v5i1.1485 UNIVERSITAS (León): Revista Científica de la UNAN León Vol.5(1) 2014, pp 126-145La investigación se centró en determinar edad de inicio, factores de riesgo/protección, prevalencia e incidencia del consumo de sustancias psicoactivas lícitas e ilícitas. Se utilizó la metodología de la CICAD-OEA-SIDUC (sistema de vigilancia contra las drogas en el hemisferio) empleada en estudios nacionales, de Latinoamérica y el Caribe. La presente tesis contiene un enfoque clínico epidemiológico en la salud pública basada en un estudio descriptivo de corte transversal con una población constituida por 1,116 estudiantes adolescentes y una muestra representativa de 286 escolares de ambos sexos, se aplicó el cuestionario estandarizado SIDUC con indicadores predeterminados para medir tasas de prevalencia y patrones de consumo. Resultados y conclusiones evidencian que entre las drogas licitas el alcohol posee las mayores prevalencias entre los estudiantes: consumo experimental 45.5%, reciente 28.3% y actual 19.9%, seguido por el tabaco, entre las drogas ilícitas la mariguana posee las mayores prevalencias: consumo experimental 13.6%, reciente 6.3% y actual 2.8%, seguida por la cocaína. Las prevalencias indican mayores porcentajes de consumo entre los varones, la jornada vespertina, el décimo grado y las edades entre 15-17 años. Son factores de riesgo la calle y eventos sociales, las edades de inicio cada vez más tempranas, con una edad media de 11.6 años y el entorno de pares. Son factores protectores de los estudiantes las expectativas futuras positivas y la percepción de “gran riesgo” hacia el consumo de drogas.DOI: http://dx.doi.org/10.5377/universitas.v5i1.1485 UNIVERSITAS (León): Revista Científica de la UNAN León Vol.5(1) 2014, pp 126-14

    An?lisis del desarrollo del sector de generaci?n de energ?a el?ctrica en Nicaragua

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    El sector energ?tico es clave para lograr el desarrollo y aumentar la competitividad de un pa?s. A nivel mundial el sector ha venido impulsando una mayor sostenibilidad a trav?s de la incorporaci?n de energ?as renovables. A trav?s de esta investigaci?n se identificaron los Factores Cr?ticos de ?xito para la industria de generaci?n de energ?a el?ctrica en Nicaragua. Los Factores Cr?ticos de ?xito identificados son: (1) Estructura del sector, (2) Matriz energ?tica, (3) Gesti?n de la demanda, (4) Marco Regulatorio, (5) Planificaci?n, (6) Sustentabilidad, (7) Gesti?n Gubernamental y (8) Situaci?n econ?mica del pa?s. En el caso de Nicaragua, el pa?s presenta grandes retos en el desarrollo de la industria de generaci?n, sobre todo porque posee una de las tarifas el?ctricas m?s altas de la regi?n, afectando de esta manera su competitividad. Por otro lado, cuenta con un mercado el?ctrico mayorista regulado. Participa en el mercado de ocasi?n y mercado de contratos. Por su ubicaci?n, tiene acceso al mercado el?ctrico regional, sin embargo, su oferta de generaci?n no es competitiva en comparaci?n con los pa?ses de la regi?n centroamericana

    Noise2Recon: Enabling Joint MRI Reconstruction and Denoising with Semi-Supervised and Self-Supervised Learning

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    Deep learning (DL) has shown promise for faster, high quality accelerated MRI reconstruction. However, supervised DL methods depend on extensive amounts of fully-sampled (labeled) data and are sensitive to out-of-distribution (OOD) shifts, particularly low signal-to-noise ratio (SNR) acquisitions. To alleviate this challenge, we propose Noise2Recon, a model-agnostic, consistency training method for joint MRI reconstruction and denoising that can use both fully-sampled (labeled) and undersampled (unlabeled) scans in semi-supervised and self-supervised settings. With limited or no labeled training data, Noise2Recon outperforms compressed sensing and deep learning baselines, including supervised networks, augmentation-based training, fine-tuned denoisers, and self-supervised methods, and matches performance of supervised models, which were trained with 14x more fully-sampled scans. Noise2Recon also outperforms all baselines, including state-of-the-art fine-tuning and augmentation techniques, among low-SNR scans and when generalizing to other OOD factors, such as changes in acceleration factors and different datasets. Augmentation extent and loss weighting hyperparameters had negligible impact on Noise2Recon compared to supervised methods, which may indicate increased training stability. Our code is available at https://github.com/ad12/meddlr

    Plasma Amyloid and in vivo Brain Amyloid in Late Middle-Aged Hispanics

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    BACKGROUND: Determining amyloid positivity is possible with cerebrospinal fluid and brain imaging of amyloid, but these methods are invasive and expensive. OBJECTIVE: To relate plasma amyloid-β (Aβ), measured using Single-molecule array (Simoatrademark) assays, to in vivo brain Aβ, measured using positron emission tomography (PET), examine the accuracy of plasma Aβ to predict brain Aβ positivity, and the relation of APOE ɛ4 with plasma Aβ. METHODS: We performed a cross-sectional analysis in a cohort of 345 late middle-aged Hispanic men and women (age 64 years, 72% women). Our primary plasma variable was Aβ 42/Aβ 40 ratio measured with Simoa. Brain Aβ burden was measured as global SUVR with 18F-Florbetaben PET examined continuously and categorically. RESULTS: Plasma Aβ 42/Aβ 40 ratio was inversely associated with global Aβ SUVR (β= -0.13, 95% Confidence Interval (CI): -0.23, -0.03; p = 0.013) and Aβ positivity (Odds Ratio: 0.59, 95% CI: 0.38, 0.91; p = 0.016), independent of demographics and APOE ɛ4. ROC curves (AUC = 0.73, 95% CI: 0.64, 0.82; p <  0.0001) showed that the optimal threshold for plasma Aβ 42/Aβ 40 ratio in relation to brain Aβ positivity was 0.060 with a sensitivity of 82.4% and specificity of 62.8% . APOE ɛ4 carriers had lower Aβ 42/Aβ 40 ratio and a higher Aβ positivity determined with the Aβ 42/Aβ 40 ratio threshold of 0.060. CONCLUSION: Plasma Aβ 42/Aβ 40 ratio assayed using Simoa is weakly correlated with in vivo brain amyloid and has limited accuracy in screening for amyloid positivity and for studying risk factors of brain amyloid burden when in vivo imaging is not feasible
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