We present the results of a three‐continent multisite photometric campaign carried out on the Algol‐type eclipsing binary system RZ Cas, in which the primary component has recently been discovered to be a δ Sct‐type pulsator. The present observations include, for the first time, complete simultaneous Strömgren uvby light curves together with a few Crawford Hβ data collected around the orbital phase of the first quadrature. The new observations confirm the pulsational behaviour of the primary component. A detailed photometric analysis, based on these observations, is presented for both binarity and pulsation. The results indicate a semidetached system where the secondary fills its Roche lobe. The appearance of the light curves reveals the presence of the mass stream from the secondary component and a hotspot where this stream impacts on the surface of the primary star. There are also some indications of chromospheric activity in the secondary. On the other hand, the pulsational behaviour out‐of‐primary eclipse can be well described with only one frequency at 64.1935 cd−1 similar to the main peak found by Ohshima et al. The existence of multiperiodicity is not confirmed in our data. Concerning the mode identification, our results indicate non‐radial pulsation in a high radial order (n= 6), with l= 2, |m|= 1, 2 as the most suitable. However, additional effects must be taken into account in the predictions. Moreover, the pulsation amplitude in the u band is larger than in b and v, which is unusual among the δ Sct‐type variables. This can be explained as due to pulsation in a high n value and close to the blue edge of the δ Sct region. On the other hand, the early data of Ohshima et al. have also been analysed and similar results are found concerning the frequency content and pulsational amplitude. Finally, a revision of all the photometric out‐of‐primary‐eclipse data sets available in the literature is made together with some additional unpublished data leading to interesting findings relative to changes taking place in the pulsation amplitudes and frequencies from season to season. Furthermore, multiperiodicity is probably present in some epochs.
This paper presents simultaneous Strömgren uvby observations carried out during the years 1998 and 1999 on the Algol-type eclipsing binary system AB Cas, where the primary component is a δ Sct-type pulsator. These observations include complete binary uvby light curves which have been analysed using the Wilson-Devinney code. The new results are compared with those from the literature. The residuals from the computed binary light curves were then analysed for their pulsational content. A single frequency was found to be sufficient to describe the out-of-eclipse pulsational behaviour. Nevertheless, some indications of the existence of secondary frequencies are also found. The main period was found to be constant during the last twenty years, making use of the classical O − C method, but an increase in its amplitude is detected during the year 1998 as compared with other epochs. Concerning the nature of the pulsations, methods based on the phase shifts and amplitude ratios between different filters were used for out-of-eclipse data and the Spatial Filtration method for observations during the primary eclipses. All methods lead to the same result: the dominant pulsation is radial, confirming previous results from earlier works. In fact, neither significant amplitude variations nor phase shifts, relative to the pulsational out-of-eclipse behaviour, are found when the primary component is hidden during primary eclipse. An iterative process was also carried out to improve both the binary and pulsation solutions, but the final results remained essentially the same.
The Internet of Things (IoT) has empowered the development of a plethora of new services, fueled by the deployment of devices located at the edge, providing multiple capabilities in terms of connectivity as well as in data collection and processing. With the inception of the Fog Computing paradigm, aimed at diminishing the distance between edge-devices and the IT premises running IoT services, the perceived service latency and even the security risks can be reduced, while simultaneously optimizing the network usage. When put together, Fog and Cloud computing (recently coined as fog-to-cloud, F2C) can be used to maximize the advantages of future computer systems, with the whole greater than the sum of individual parts. However, the specifics associated with cloud and fog resource models require new strategies to manage the mapping of novel IoT services into the suitable resources. Despite few proposals for service offloading between fog and cloud systems are slowly gaining momentum in the research community, many issues in service placement, both when the service is ready to be executed admitted as well as when the service is offloaded from Cloud to Fog, and vice-versa, are new and largely unsolved. In this paper, we provide some insights into the relevant features about service placement in F2C scenarios, highlighting main challenges in current systems towards the deployment of the next-generation IoT services.
Fog Computing recently came up as an extension of cloud computing to facilitate the development of IoT services with strong requirements in latency, security while minimizing the traffic load in the network. The stack of resources set by putting together fog and cloud premises has been recently coined as Fog-to-Cloud (F2C) computing, and has been positioned as an innovative computing paradigm best matching current and foreseen IoT services demands. This paper emphasizes the benefits F2C may bring to a particular health area, namely COPD, whose patients' quality of life intensely depends on the patients mobility. We argue that by enriching current breath assistance systems for COPD patients with F2C capacities, the patients may comfortably afford physical activities, therefore\ud impacting on reducing not only patients deterioration but also the re-admission incidence rate IRR) with a clear impact on the health costs as wellPostprint (published version
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