4,057 research outputs found

    How Much Water Do Households Require?

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    What is the basic water requirement per month of a Philippine household consisting of six members? This study provides an estimate based on various household activities dovetailed to local practices and situation which may serve as a valuable input in water sector planning, water supply allocation, and water pricing determination.water sector, water demand

    A novel approach to improve the bank ranking process: an empirical study in Spain

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    In this paper, a novel approach to the bank ranking process based on the possibilistic theory is proposed. Through this new method, the sensitivity of the results can be improved. Several methods are applied in order to rank the financial performance of Spanish Banks. Methods such as the Fuzzy Analytic Hierarchy Process (FAHP) and fuzzy TOPSIS are integrated in the proposed model. Criteria and sub-criteria weights are computed based on the judgments of experts using FAHP. These weights and financial indicators are inputs of the fuzzy TOPSIS methods for ranking the banks. The financial ratios are based on the CAMEL rating system criteria. Moreover, the results from the application of several distance measurements (Vertex, Hamming and Euclidean) in fuzzy TOPSIS as well as a new measure based on the possibilistic theory are compared. Finally, the results obtained applying fuzzy TOPSIS show that they vary depending on the separate measure, so it is necessary to have different measures to be able to correct decision making

    OH rotational lines as a diagnostic of the warm neutral gas in galaxies

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    We present Infrared Space Observatory (ISO) observations of several OH, CH and H2O rotational lines toward the bright infrared galaxies NGC253 and NGC1068. As found in the Galactic clouds in SgrB2 and Orion, the extragalactic far-IR OH lines change from absorption to emission depending on the physical conditions and distribution of gas and dust along the line of sight. As a result, most of the OH rotational lines that appear in absorption toward NGC253 are observed in emission toward NGC1068. We show that the far-IR spectrum of OH can be used as a powerful diagnostic to derive the physical conditions of extragalactic neutral gas. In particular, we find that a warm (Tk~150 K, n(H2)< 5 10^4 cm^-3) component of molecular gas with an OH abundance of 10^{-7} from the inner <15'' can qualitatively reproduce the OH lines toward NGC253. Similar temperatures but higher densities (5 10^5 cm^-3) are required to explain the OH emission in NGC1068.Comment: 5 pages, 4 figures, accepted in ApJ Part I (2004, October 6

    Transient Thermal Analysis of a Railroad Bearing Adapter for Optimal Placement of Onboard Sensors

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    Bearing temperature serves as an important metric used in identifying defective bearings in the rail industry. Current defect detection systems, such as the Hot Box Detectors (HBDs), are used to measure the temperature of freight car roller bearings. The HBD is a wayside device that utilizes a non-contact infrared sensor to determine the operating temperature of a railroad bearing as it passes over the HBD. Railroads analyze the data collected by HBDs to detect and flag defective bearings. If the operating temperature of a bearing surpasses a predetermined threshold, an emergency stop is initiated, and the bearing is removed from service and sent for inspection. One major drawback of HBDs is that they have been associated with many “false positives,” which has resulted in costly train stoppages and delays. To combat that, researchers have opted to use wireless onboard sensor devices mounted directly on the bearing adapter. One such device is the wireless onboard health monitoring system developed by the University Transportation Center for Railway Safety (UTCRS) that utilizes temperature and vibration sensors to detect the condition of rolling stock. However, because the device is affixed to the bearing adapter and not the bearing itself, the strategic placement of the temperature sensor on the adapter is crucial in minimizing the thermal lag associated with the heat transfer from the bearing to the location where the temperature is measured, as this will directly affect the accuracy of the readings. By conducting a transient heat transfer finite element analysis (FEA), the estimated time-lag and the temperature distribution within the bearing adapter can be determined. To validate the accuracy of the transient FEA model, the results were compared to data acquired from laboratory testing performed on the UTCRS dynamic bearing test rigs. The results obtained in this study can be used to identify optimal anchor points for the temperature sensors on the bearing adapter, and in turn, increase the proficiency of wireless onboard sensor devices in detecting defective components

    A data-driven health assessment method for electromechanical actuation systems

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    The design of health assessment applications for the electromechanical actuation system of the aircraft is a challenging task. Physics-of-failure models involve non-linear complex equations which are further complicated at the system-level. Data-driven techniques require run-to-failure tests to predict the remaining useful life. However, components are not allowed to run until failure in the aerospace engineering arena. Besides, when adding new monitoring elements for an improved health assessment, the airliner sets constraints due to the increased cost and weight. In this context, the health assessment of the electromechanical actuation system is a challenging task. In this paper we propose a data-driven approach which estimates the health state of the system without run-to-failure data and limited health information. The approach combines basic reliability theory with Bayesian concepts and obtained results show the feasibility of the technique for asset health assessment

    A model for the electromagnetic spectrum of the inner jets of Cen A

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    Centaurus A, the closest active galaxy, has been detected from radio to high-energy gamma-rays. The synchrotron radiation by extremely high energy protons may be a suitable mechanism to explain the MeV to GeV emission detected by the instruments of the Compton Gamma-Ray Observatory, as coming from the inner jets. This scenario requires a relatively large magnetic field of about 10^4 G that could be present only close to the central black hole. We investigate the spectral energy distribution (SED) resulting from a one-zone compact acceleration region, where both leptonic and hadronic relativistic populations arise. We present here results of such a model, where we have considered synchrotron radiation by primary electrons and protons, inverse Compton interactions, and gamma-ray emission originated by the inelastic hadronic interactions between relativistic protons and cold nuclei within the jets themselves. Photo-meson production by relativistic hadrons were also taken into account, as well as the effects of secondary particles injected by all interactions. The internal and external absorption of gamma rays is shown to be of great relevance to shape the observable SED, which was also recently constrained by the results of HESS.Comment: 13 pages (ref. style), submitted to MNRAS on December 04, 2008. Waiting for revie

    Tyche: Stochastic In-Context Learning for Medical Image Segmentation

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    Existing learning-based solutions to medical image segmentation have two important shortcomings. First, for most new segmentation task, a new model has to be trained or fine-tuned. This requires extensive resources and machine learning expertise, and is therefore often infeasible for medical researchers and clinicians. Second, most existing segmentation methods produce a single deterministic segmentation mask for a given image. In practice however, there is often considerable uncertainty about what constitutes the correct segmentation, and different expert annotators will often segment the same image differently. We tackle both of these problems with Tyche, a model that uses a context set to generate stochastic predictions for previously unseen tasks without the need to retrain. Tyche differs from other in-context segmentation methods in two important ways. (1) We introduce a novel convolution block architecture that enables interactions among predictions. (2) We introduce in-context test-time augmentation, a new mechanism to provide prediction stochasticity. When combined with appropriate model design and loss functions, Tyche can predict a set of plausible diverse segmentation candidates for new or unseen medical images and segmentation tasks without the need to retrain

    Pattern of Activated Pathways and Quality of Collateral Status in Patients with Symptomatic Internal Carotid Artery Occlusion

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    Background: Internal carotid artery occlusion (ICAO) is an important risk factor for stroke. Cerebral hemodynamics in patients with ICAO depends on the individual capacity to activate sufficient collateral pathways. Therefore, the assessment of intracranial collaterals is essential for the acute and long-term management of these patients and accurate estimation of further stroke risk. Methods: Acute stroke patients with unilateral ICAO were prospectively enrolled. We assessed the following collaterals by transcranial color-coded sonography (TCCS): the anterior and posterior communicating artery (ACoA, PCoA), the ophthalmic artery (OA), and leptomeningeal collaterals of the posterior cerebral artery (LMC). We subdivided the flow pattern of the Doppler spectrum in the middle cerebral artery (MCA) into 3 categories: (1) good, (2) moderate, and (3) bad according to the hemodynamic effects on the ipsilateral MCA flow. Finally, we compared the individual TCCS results with the stroke pattern detected on CT or MRI scan. Results: One hundred thirteen patients (age 66 +/- 12 years; female 24) were included. The collateral status was good, moderate, and bad in 59 (52%), 37 (33%), and 17 (15%) patients, respectively. The ACoA collateral was most frequently activated (81%), followed by the OA (63%), the PCoA (53%), and the LMC (22%). The quality of the collateral status was determined by the type (p = 0.0003) but not by the number (p = 0.19) of activated collateral pathways. Good collateral function was highly associated with primary collaterals (ACoA > PCoA). Best parameter for a good collateral status was an antegrade flow in the OA, indicating a high blood supply via the communicating arteries. Conclusions: TCCS allows the assessment of intracranial collaterals and their hemodynamic capacity. Prevalence of collateral sufficiency in ICAO seems to be higher than previously reported. ACoA cross flow is essential for the optimal hemodynamic compensation of ICAO. Antegrade OA flow indicates good collateral status

    Entropy based parametrization of soils: Models and Tools

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    Particle-size distribution (PSD) is a fundamental soil physical property. The PSD is commonly reported in terms of the mass percentages of sand, silt and clay present

    Progress report on the MEDAMI 2019 and CTR research at the DMIL in i3M

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    [EN] This contribution reports on the recently held MEDAMI 2019 workshop in Valencia (15-17th May 2019). This workshop is about advanced molecular imaging and the main topic of this last edition was Imaging in Immunotherapy. Around 70 attenders met together during three days. This meeting made it possible to join medical doctors and instrumentalists. In MEDAMI 2019 it was exposed the new immunotherapies from a clinical and research point of view. It was shown the already observed improvements when using these therapies. At the same time, we heard about the difficulties and limitations of current molecular imaging in this particular field. It was clear that improvements in system sensitivity and resolution are demanded. Timing information can be utilized in different ways to improve the image quality in PET systems. Precise Coincidence Time Resolution (CTR) improves the signal-to-noise ratio and, therefore, the image contrast, allowing for instance to distinguish low uptake tumors, multicentric lesions, or tumor heterogeneity, to name but a few. Both high time resolution and angular coverage in a PET system can improve the effective sensitivity. An example of a system benchmarking the timing resolution is the Siemens Biograph Vision with 214 ps FWHM, enhancing the detectability. The Explorer total-body PET from UC Davis improves the system sensitivity by having a 2 meters long PET scanner. Deep investigations, from different research groups, are being carried out to further push the limits of timing resolution. This work also describes some of the projects on high timing performance that are being carried out at the Detector for Molecular Imaging Lab (DMIL) at the Institute for Instrumentation in Molecular Imaging (i3M) in Valencia. The DMIL group has extensively worked on detectors and implementation of PET systems enabling the use of accurate timing information. In this progress report we describe the results obtained at the DMIL regarding timing determination in gamma-ray detectors both based on monolithic and pixelated crystals. Although with 15 min thick LYSO blocks it was tough to obtain values of CTR below 500 ps when using analog SiPMs and ASIC-based readout, this was improved down to 250 ps if small 3 mm size and 6 mm height pixels under the one-to-one coupling approach were enabled. This type of approach, the one-to-one coupling, seems to benefit from the light collection in a single photosensor element and, therefore, to improve the timing properties. Monolithic blocks offer, on the contrary, advantages such as photon depth of interaction. In order to separate Compton and photoelectric events we have thought of a detector block design with a high aspect ratio, using LYSO crystals of 51 mm size vs. 3 mm thickness, read-out by the four lateral sides. We have demonstrated the possibility to reach below 2 mm FWHM spatial resolution with an energy resolution of 12%.The DMIL work presented in this paper has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (grant agreement No. 695536). It has also been supported by the Spanish Ministerio de Economia, Industria y Competitividad under Grant TEC2016-79884-C2-1-R. The author would like to thank all current and former members of the DMIL at i3M for their continuous contributions to this work.González Martínez, AJ.; Barrio, J.; Lamprou, E.; Ilisie, V.; Sánchez Martínez, F.; Benlloch Baviera, JM. (2020). Progress report on the MEDAMI 2019 and CTR research at the DMIL in i3M. Il Nuovo cimento C. 43(1):1-10. https://doi.org/10.1393/ncc/i2020-20005-8S11043
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