731 research outputs found
Contact Tracing Platform in OSN for Prevention of Infectious Disease Outbreaks
No full textTo limit the spread of COVID-19, social distancing measurements and contact tracing have become popular strategies implemented worldwide. In addition to manual contact tracing, smartphone-based applications based on proximity detection have emerged to speed up the discovery of potential infectious individuals. However, so far, their effectiveness has been limited, mainly due to privacy issues. A new tracing mechanism is represented by Online Social Networks (OSNs), which provide a successful way to track, share and exchange information in real-time. Being extremely popular and largely used by citizens, OSNs are less exposed to privacy concerns. In this paper, we present an OSN-based contact tracing platform called TraceMe to reduce the spread of the epidemic. The proposal currently targets COVID-19, but it can be used in presence of other infectious diseases, like Ebola, swine flue, etc. TraceMe implements conventional contact tracing based on physical proximity and, in addition, it leverages OSNs to identify other contacts potentially exposed to the virus. To efficiently find the targeted social community, while saving the time complexity, a clique-based method is applied. Performance evaluation based on a realistic dataset shows that TraceMe is able to analyse large-scale social networks in order to find, and then alert, the tight communities of contacts that are at high risk of infection
Collective excitations in the superdeformed well
No full textCollective excitations are commonplace features in nuclei at normal deformation. It has been suggested that both in the A\sim 190 and 150 superdeformed (SD) nuclei, collective vibrational states might occur in the same excitation energy range as quasi-particle and single-particle excitations. In particular, the large deformation associated with SD nuclei brings together orbitals from many spherical shells and leads to the close proximity of states with opposite parity, favouring octupole shape vibrations. However, to date, \sim 200 SD bands have been reported in more than 50 nuclei and in most cases, the excited SD bands have been interpreted as single or quasi-particle excitations. Only in very few cases, has the collective excitation scenario been suggested. Where are the collective states in SD nuclei? The question is particularly relevant in even--even A=190 nuclei in which SD states are observed at lower rotational frequency and hence the additional influence of the pair gap makes the collective excitations more competitive with quasi-particle excitations.F. Hannachi, A. Korichi, A.N. Wilson, A. Lopez-Martens, M. Rejmund, C. Schueck, Ch. Vieu, G. Chmel, A. Goergen, H. Huebel, D. Rossbach, S. Schoenwasser, M. Bergstroem, B.M. Nyako, J. Timar, D. Bazzacco, S. Lunardi, C. Rossi-Alvarez, P. Bednarczyk, N. Kintz, S. Naguleswaran, A. Astier, D.M. Cullen, J.F. Sharpey-Schafer, T. Lauritsen, R. Wadsworthhttp://th-www.if.uj.edu.pl/acta/vol32/abs/v32p1083.ht
To Debate or not to Debate: Third-Year ENSL Students’ Views on Using Debate to Promote Critical Thinking in the Speaking Class
No full textAbstract: In a world where critical thinking has become an essential means for survival, its inclusion as part of education’s goals is a necessity now. This study aimed at discovering students’ opinions regarding the usefulness of debate as a pedagogical tool to improve their critical thinking skills. Applying a single group quasi-experimental research design using a mixed methods approach, an intervention was carried out. A debate-based instructional model to improve students’ critical thinking skills was implemented in an EFL Speaking class in ENSL in Algeria. After the intervention, 50 students responded to the online questionnaire that was sent to them in order to discover their views. The analysis procedures of the collected data included using SPSS 24 for quantitative data treatment, a deductive thematic approach to qualitative data, and observation was used to support the results. The findings revealed that the participants considered debate to be effective as a way to foster their critical thinking demonstrated through reflection and evidence-based thinking. Besides, their oral communication skills that included overcoming fear of public speaking, increasing self-esteem, body language, teamwork, and leadership improved.
Keywords: critical thinking, debate, quasi-experiment, students’ views, speakin
Linear polarization measurement of interband transitions in superdeformed (190)Hg: model-independent evidence for octupole vibrational structures
No full textThe linear polarization of γ rays between excited and yrast superdeformed (SD) states in 190Hg was measured using the four-element CLOVER detectors of the EUROBALL IV γ-ray spectrometer. This measurement shows in a model-independent way that the interband transitions which compete with the highly collective in-band quadrupole transitions are largely enhanced electric dipoles. Not only do these results represent the first measurement of the multipolarity of transitions between different SD states, but they also provide strong evidence for the interpretation of the structures in the SD minimum of the A∼190 region in terms of octupole excitations.A. Korichi, A. N. Wilson, F. Hannachi, A. Lopez-Martens, M. Rejmund, C. Schück, Ch. Vieu, G. Chmel, A. Görgen, H. Hübel, D. Rossbach, S. Schönwasser, M. Bergström, B. M. Nyakó, J. Timár, D. Bazzacco, S. Lunardi, C. Rossi-Alvarez, P. Bednarczyk, N. Kintz, S. Naguleswaran, A. Astier, D. M. Cullen, J. F. Sharpey-Schafer, T. Lauritsen, and R. Wadswort
TraceMe: Real-Time Contact Tracing and Early Prevention of COVID-19 based on Online Social Networks
No full textPerformance of the Advanced GAmma Tracking Array at GANIL
No full textThe performance of the Advanced GAmma Tracking Array (AGATA) at GANIL is discussed, on the basis of the analysis of source and in-beam data taken with up to 30 segmented crystals. Data processing is described in detail. The performance of individual detectors are shown. The efficiency of the individual detectors as well as the efficiency after γ-ray tracking are discussed. Recent developments of γ-ray tracking are also presented. The experimentally achieved peak-to-total is compared with simulations showing the impact of back-scattered γ rays on the peak-to-total in a γ-ray tracking array. An estimate of the achieved position resolution using the Doppler broadening of in-beam data is also given. Angular correlations from source measurements are shown together with different methods to take into account the effects of γ-ray tracking on the normalization of the angular correlations
Contributions to the stochastic optimal control of Mckean-Vlasov stochastic différential systems via the derivatives with respect to measures with some applications
No full textThe central theme is to establish a set of necessary conditions, in the form of stochastic maximum for a di¤erent systems. This thesis is structured around …ve chapters : The …rst chapter is essentially a reminder. We presents some concepts and results that allow us to prove our results, such as stochastic processes, conditional expectation, martingales, Itô formulas, di¤erent methods of solving of optimal control (maximum principle, which has been introduced by Pontryagin et al and dynamical programming principle, wich
has been introduced by Bellman) with some di¤erent class of stochastic control, (feedback,
singular, impulsional, relaxed, near-optimal, ...etc. In the second chapter, we present the method of the derivative with respect to probability measure. This new approch of derivatives has been introduced by P.L Lions "Cours au Collège de France : Théorie des jeu à champs moyens. http ://www. collegede-france.fr/default/EN/all/equ[1]der/audiovideo.jsp. (2013) » Recently, in the third chapter of this thesis, we study partially observed optimal stochastic singular control problems of general mean-…eld with correlated noises between the system and the observation. The control variable has two components, the …rst being absolutely continuous and the second is a bounded variation, non decreasing continuous on the right with left limits. The dynamic system is governed by Itô-type controlled stochastic differential equation with jumps. The coe¢ cients of the dynamic depend on the state process as well as of its probability law and the continuous control variable.In this work, we formulate this problem mathematically as a combined stochastic continuous control and irregular control problem. We study partially observed optimal stochastic intervention control problem for systems governed by mean-…eld SDEs with correlated noisy between the system and the observation, allowing both classical and intervention control: In the fourth chapter, we establish a second-order stochastic maximum principle for optimal stochastic control of stochastic di¤erential equations of general mean-…eld type. 11Abstract, Korichi. F. 2024 The coe¢ cients of the system are nonlinear and depend on the state process as well as of its probability law. The control variable is allowed to enter into both drift and di¤usion terms. We establish a set of second-order necessary conditions for the optimal control in integral form. The control domain is assumed to be convex. The proof of our main result is based on the the …rst and second-order derivatives with respect to the probability law and by using
a convex perturbation with some appropriate estimates. In the …fth chapter, a maximum principle for stochastic model governed by mean-…eld nonlinear controlled Itô-stochastic differential equations is proved. We study the following mean-…eld-type stochastic optimal nonlinear control problem : Minimize a mean-…eld cost functional J (�(�)) = E ZRd �(y�(�); �y�(�))�(dy�); subject to y�(�) solution of the (MF-SDE) : t 2 [0; �] 8>>>>>>>>>: dy�(t) = RRd ' t; y�(t); �y�(t); �(t)� �(dy�)dt + RRd t; y�(t); �y�(t); �(t)� �(dy�)dW(t);
y�(0) = y0: where, �(�) is the control variable valued in a convex bounded subset U � Rk, y� (�) is the controlled state variable, W(�) is a standard Brownian motion, �y�(t) is the distribution of
y�(t
- …
