| 1. |
- Tinetti, Giovanna, et al.
(författare)
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The EChO science case
- 2015
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Ingår i: Experimental astronomy. - : Springer Science and Business Media LLC. - 0922-6435 .- 1572-9508. ; 40:2-3, s. 329-391
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Tidskriftsartikel (refereegranskat)abstract
- The discovery of almost two thousand exoplanets has revealed an unexpectedly diverse planet population. We see gas giants in few-day orbits, whole multi-planet systems within the orbit of Mercury, and new populations of planets with masses between that of the Earth and Neptune-all unknown in the Solar System. Observations to date have shown that our Solar System is certainly not representative of the general population of planets in our Milky Way. The key science questions that urgently need addressing are therefore: What are exoplanets made of? Why are planets as they are? How do planetary systems work and what causes the exceptional diversity observed as compared to the Solar System? The EChO (Exoplanet Characterisation Observatory) space mission was conceived to take up the challenge to explain this diversity in terms of formation, evolution, internal structure and planet and atmospheric composition. This requires in-depth spectroscopic knowledge of the atmospheres of a large and well-defined planet sample for which precise physical, chemical and dynamical information can be obtained. In order to fulfil this ambitious scientific program, EChO was designed as a dedicated survey mission for transit and eclipse spectroscopy capable of observing a large, diverse and well-defined planet sample within its 4-year mission lifetime. The transit and eclipse spectroscopy method, whereby the signal from the star and planet are differentiated using knowledge of the planetary ephemerides, allows us to measure atmospheric signals from the planet at levels of at least 10(-4) relative to the star. This can only be achieved in conjunction with a carefully designed stable payload and satellite platform. It is also necessary to provide broad instantaneous wavelength coverage to detect as many molecular species as possible, to probe the thermal structure of the planetary atmospheres and to correct for the contaminating effects of the stellar photosphere. This requires wavelength coverage of at least 0.55 to 11 mu m with a goal of covering from 0.4 to 16 mu m. Only modest spectral resolving power is needed, with R similar to 300 for wavelengths less than 5 mu m and R similar to 30 for wavelengths greater than this. The transit spectroscopy technique means that no spatial resolution is required. A telescope collecting area of about 1 m(2) is sufficiently large to achieve the necessary spectro-photometric precision: for the Phase A study a 1.13 m(2) telescope, diffraction limited at 3 mu m has been adopted. Placing the satellite at L2 provides a cold and stable thermal environment as well as a large field of regard to allow efficient time-critical observation of targets randomly distributed over the sky. EChO has been conceived to achieve a single goal: exoplanet spectroscopy. The spectral coverage and signal-to-noise to be achieved by EChO, thanks to its high stability and dedicated design, would be a game changer by allowing atmospheric composition to be measured with unparalleled exactness: at least a factor 10 more precise and a factor 10 to 1000 more accurate than current observations. This would enable the detection of molecular abundances three orders of magnitude lower than currently possible and a fourfold increase from the handful of molecules detected to date. Combining these data with estimates of planetary bulk compositions from accurate measurements of their radii and masses would allow degeneracies associated with planetary interior modelling to be broken, giving unique insight into the interior structure and elemental abundances of these alien worlds. EChO would allow scientists to study exoplanets both as a population and as individuals. The mission can target super-Earths, Neptune-like, and Jupiter-like planets, in the very hot to temperate zones (planet temperatures of 300-3000 K) of F to M-type host stars. The EChO core science would be delivered by a three-tier survey. The EChO Chemical Census: This is a broad survey of a few-hundred exoplanets, which allows us to explore the spectroscopic and chemical diversity of the exoplanet population as a whole. The EChO Origin: This is a deep survey of a subsample of tens of exoplanets for which significantly higher signal to noise and spectral resolution spectra can be obtained to explain the origin of the exoplanet diversity (such as formation mechanisms, chemical processes, atmospheric escape). The EChO Rosetta Stones: This is an ultra-high accuracy survey targeting a subsample of select exoplanets. These will be the bright "benchmark" cases for which a large number of measurements would be taken to explore temporal variations, and to obtain two and three dimensional spatial information on the atmospheric conditions through eclipse-mapping techniques. If EChO were launched today, the exoplanets currently observed are sufficient to provide a large and diverse sample. The Chemical Census survey would consist of > 160 exoplanets with a range of planetary sizes, temperatures, orbital parameters and stellar host properties. Additionally, over the next 10 years, several new ground- and space-based transit photometric surveys and missions will come on-line (e.g. NGTS, CHEOPS, TESS, PLATO), which will specifically focus on finding bright, nearby systems. The current rapid rate of discovery would allow the target list to be further optimised in the years prior to EChO's launch and enable the atmospheric characterisation of hundreds of planets.
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| 2. |
- Samreth, D., et al.
(författare)
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Geolocation with respect to persona privacy for the Allergy Diary app - a MASK study
- 2018
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Ingår i: World Allergy Organization Journal. - : BMC. - 1939-4551. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Background: Collecting data on the localization of users is a key issue for the MASK (Mobile Airways Sentinel network: the Allergy Diary) App. Data anonymization is a method of sanitization for privacy. The European Commission's Article 29 Working Party stated that geolocation information is personal data. To assess geolocation using the MASK method and to compare two anonymization methods in the MASK database to find an optimal privacy method. Methods: Geolocation was studied for all people who used the Allergy Diary App from December 2015 to November 2017 and who reported medical outcomes. Two different anonymization methods have been evaluated: Noise addition (randomization) and k-anonymity (generalization). Results: Ninety-three thousand one hundred and sixteen days of VAS were collected from 8535 users and 54,500 (58. 5%) were geolocalized, corresponding to 5428 users. Noise addition was found to be less accurate than k-anonymity using MASK data to protect the users' life privacy. Discussion: k-anonymity is an acceptable method for the anonymization of MASK data and results can be used for other databases.
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| 3. |
- Morais de Lima, Ana Paula, et al.
(författare)
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Framework for Planning and Evaluation of Nature-Based Solutions for Water in Peri-Urban Areas
- 2022
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Ingår i: Sustainability. - : MDPI. - 2071-1050. ; 14:13
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Tidskriftsartikel (refereegranskat)abstract
- Recent efforts to achieve social, economic, and environmental goals related to sustainability emphasize the importance of nature-based solutions (NBS), as grey infrastructure alone is insufficient to address current challenges. The majority of frameworks proposed in the literature fail to address the full potential of NBS, neglecting long-term results, unintended consequences, co-benefits, and their contribution to achieving global environmental agreements, such as the Agenda 2030, especially for water management in a peri-urban context. Here we present an innovative framework that can be applied to both NBS project planning and evaluation for several water-based challenges, giving practitioners and researchers a tool not only to evaluate ongoing projects but also to guide new ones. The framework considers three main stages of a NBS project: (1) context assessment, (2) NBS implementation and adaptation process, and (3) NBS results. This tool has the potential to be used to evaluate whether NBS projects are aligned with sustainability dimensions through a set of adaptable sustainability indicators. The framework can also highlight how the NBS targets are related to the sustainable development goals (SGD) and contribute to catalyzing the 2030 Agenda. The framework is an important tool for water management and other NBS types.
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| 4. |
- Lingrand, D., et al.
(författare)
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Ordinateur porté : dispositifs d’entrée sortie
- 2005
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Ingår i: Proceedings of the 17th international conference on Francophone sur l'Interaction Homme-Machine. - New York : ACM Press. ; , s. 219-222
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Konferensbidrag (refereegranskat)abstract
- Among the different challenges induced by Wearable Computing, is the one of IO devices. The choice of appropriate input device is driven by the user context and the availability of motor resources of the user. The substitution of one device by another with same functionalities is not sufficient. After the introduction of input devices classification, we show that it is necessary to introduce a user model for input devices considerations. A simple example based on motor resources of the user permit to illustrate our method. Copyright 2005 ACM.
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| 5. |
- Morais, Guilherme S., et al.
(författare)
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Transient Stability and Protection Evaluation of Distribution Systems with Distributed Energy Resources
- 2022
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Ingår i: Intelligent Control and Smart Energy Management. - Cham : Springer Nature. ; , s. 343-393
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- The connection of distributed energy resources (DERs) in power distribution systems (PDSs) may bring new technical issues that must be analyzed and discussed by distribution companies, and the distribution system operator (DSO) must be aware about them. The issues could be complications in regard to the system voltage profile, power quality, power flow control, energy management, and frequency control and protection. Understanding the impacts on the dynamic behavior of PDSs caused by the presence of DERs is fundamental to guarantee the operation within the criteria established by regulatory agencies. This work presents an analysis of unbalanced distribution systems. Therefore, a modified version of the IEEE 34-node system in the presence of a synchronous distributed generation (SG) and some photovoltaic generation systems (PVs) is chosen. After multiple simulations carried out using DIgSILENT PowerFactory software, a total of five scenarios were selected to show the voltage stability analysis and the influences of protection system in the stability and integrity of the machines and to demonstrate the behavior of synchronous machine in a true way. The events include faults, reclosing operation, islanding, and changing the number of PVs connected, in which the operational limits of the SG are evaluated. In addition, the protection schemes must satisfy the performance requirements of selectivity, reliability, and sensitivity in order to ensure the safety of the system. Thus, this work focuses beyond the conventional protection schemes based on overcurrent detection, being introduced with other complementary functions. The results show some changes with regard to the voltage profile along the feeder due to the variation of PVs connected to the system, in which a greater number increase the voltage system. Besides, the behavior of one of the PVs is analyzed, being observed the contribution of reactive power during the short-circuit event. Other important achievements are related to the protection scheme adopted, in which using more sensitive adjustments by the protection devices may prevent excessive torsional efforts and help to avoid the loss of system stability.
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