Possible solution to the riddle of HD 82943 multiplanet system: the three-planet resonance 1:2:5?

We carry out a new analysis of the published radial velocity data for the planet-hosting star HD82943. We include the recent Keck/HIRES measurements as well as the aged but much more numerous CORALIE data. We find that the CORALIE radial velocity measurements are polluted by a systematic annual variation which affected the robustness of many previous results. We show that after purging this variation, the residuals still contain a clear signature of an additional $\sim 1100$ days periodicity. The latter variation leaves significant hints in all three independent radial velocity subsets that we analysed: the CORALIE data, the Keck data acquired prior to a hardware upgrade, and the Keck data taken after the upgrade. We mainly treat this variation as a signature of a third planet in the system, although we cannot rule out other interpretations, such as long-term stellar activity. We find it easy to naturally obtain a stable three-planet radial-velocity fit close to the three-planet mean-motion resonance 1:2:5, with the two main planets (those in the 1:2 resonance) in an aligned apsidal corotation. The dynamical status of the third planet is still uncertain: it may reside in as well as slightly out of the 5:2 resonance. We obtain the value of $\sim 1075$ days for its orbital period and of $\sim 0.3 M_{\rm Jup}$ for its minimum mass, while the eccentric parameters are uncertain.Comment: 18 pages, 5 tables, 18 figures; accepted for publication in MNRA

Heterogeneous parallel multi-radio transmission system in wireless vehicular communication

In the context of growing demand for mobile data and the emergence of ve­ hicular applications, heterogeneous networks will become a necessity to meet the various requirements of future Intelligent Transport Systems. The aim of this research work is to investigate the use of heterogeneous vehicular wireless net­ works with multiple independent Radio Access Technologies (RATs). A Multiple Interface Scheduling System (MISS) is proposed, based on a user perspective, where the vehicle has visibility of all the available RATs, with no modification to the fixed infrastructure, operator independent, to improve the performance of vehicular networks. Multi RAT solutions have been reported previously where the packets are scheduled at different layers of the OSI seven-layered architecture but they require modifying the routing protocols, have one IP address per RAT or involve designing specific solution for each RAT. To overcome these limita­ tions, the proposed approach is to schedule the packets at an intermediate layer located between the network layer and the MAC layer. This solution avoids any changes to the RAT standards, and maintains a single IP address. An adaptive scheduling algorithm has been devised which is comprised of automatic wireless access interface selection, intelligent bandwidth aggregation and allocation, seamless Quality of Service (QoS) support, and context-aware packet scheduling. The system dynamically selects the most suitable wireless technology in a given space and time, or it may use the technologies j ointly to maximise the throughput, or improve the reliability that can be achieved with a single radio technology. This work focusses on the uplink, and it addresses the scenario where the vehicle is treated as a data source. The evaluated wireless technologies include cellular (4G) and Wi-Fi (802.llp and 802.lln). The proposed scheme has been simulated and implemented in hardware to validate the performance of the proposed packet scheduler. The results and hardware implementation demonstrate that the scheduling algorithm is able to transfer packets transparently over multiple RATs to provide higher availabil­ ity and/or throughput together with prioritization of selected services, without requiring any change to existing wireless standards. In terms of scalability, the intermediate layer approach is shown to be suitable for supporting connectivity by increasing the availability of uplink connection with the current infrastruc­ ture. Such an approach is not only valid for heterogeneous vehicular networks but can be used by mobile devices and the future internet of things where the goal is to upload information from different devices anywhere and at any time

Multiple interface scheduling system for heterogeneous wireless vehicular networks: Description and evaluation

Reliable wireless communications between vehicles (V2V) and between vehicles and infrastructure (V2I) will play a key role in future transport networks. Where there is overlapping coverage of multiple Radio Access Technologies, with no cooperation between them, a vehicle can use the different technologies simultaneously. This paper proposes an uplink Multi Interface Scheduling System (MISS) located at an intermediate shim layer on the user side, to achieve efficient bandwidth aggregation, or lower end-to-end packet delay. MISS aims to find all the available networks that can meet multiple criteria based on user preference and required performance. Simulation results show that safety critical traffic can be prioritized where the resources are insufficient for all the services. Video delivery quality is also improved by prioritizing the most important frames. This algorithm is ideally suited to vehicular networks, where delivery of safety traffic and/or video is an essential requirement

Recipes for calibration and validation of agent-based models in cancer biomedicine

Computational models and simulations are not just appealing because of their intrinsic characteristics across spatiotemporal scales, scalability, and predictive power, but also because the set of problems in cancer biomedicine that can be addressed computationally exceeds the set of those amenable to analytical solutions. Agent-based models and simulations are especially interesting candidates among computational modelling strategies in cancer research due to their capabilities to replicate realistic local and global interaction dynamics at a convenient and relevant scale. Yet, the absence of methods to validate the consistency of the results across scales can hinder adoption by turning fine-tuned models into black boxes. This review compiles relevant literature to explore strategies to leverage high-fidelity simulations of multi-scale, or multi-level, cancer models with a focus on validation approached as simulation calibration. We argue that simulation calibration goes beyond parameter optimization by embedding informative priors to generate plausible parameter configurations across multiple dimensions

Regulacion juridica aplicable a la securitizacion como actual alternativa de inversion

53 p.El objetivo de la presente memoria apunta principalmente al estudio sistemático, metódico y hermenéutico de la ley 19.301, que agrego el título XVIII de las Sociedades Securitizadoras, en la ley 18.045 de Mercado de Valores. Esta memoria se divide en cuatro capítulos que buscan abordar en forma integral los distintos aspectos que involucran el establecimiento y desarrollo de esta institución, la cual desde su puesta en marcha ha tenido un creciente y sostenido desarrollo en el ámbito económico y social, lo que queda de manifiesto del análisis de las cifras que involucra la securitización de activos subyacentes. Además, tenemos en consideración las numerosas modificaciones legales que permiten el auge y simplificación del proceso, con lo que se transforma en una alternativa atractiva de refinamiento y reinversión, dependiendo de los distintos factores involucrados

DISCRETE-TIME MODEL-BASED SLIDING MODE CONTROLLERS FOR TOWER CRANE SYSTEMS

This paper applies three classical and very popular discrete-time model-based sliding mode controllers, namely the Furuta controller, the Gao controller, and the quasi-relay controller due to Milosavljević, to the position control of tower crane systems. Three single input-single output (SISO) control systems are considered, for cart position control, arm angular position control and payload position control, and separate SISO controllers are designed in each control system. Experimental results are included to support the comparison of the three plus three plus three sliding mode controllers

A theoretical approach for elastically driven cooperative switching of spin crossover compounds impacted by an ultrashot laser pulse

International audienceIn this paper we use an elastic model in order to study the elastically driven cooperative switching of spin crossover materials after femtosecond laser excitation. In this model, the molecules occupy a triangular lattice in open boundaries systems and are connected by springs. The volume change of a molecule between its two possible spin states, low-spin and high-spin, determines a variation of the spring length and therefore induces elastic interactions between molecules, which propagates throughout the whole sample as elastic distortions. This model is able to reproduce the multi-step out-of-equilibrium response to ultrashort laser excitation and especially the elastically-driven cooperative response. Then this model is developed in order to predict the behaviour of the system as a function of its different physical parameters, such as the magnitude of the elastic constant or the homogeneity of the photoexcitation. The contribution of the reorganisation of the molecular states during elastic steps, leading to clusters of high-spin molecules towards edge or corners is also revealed

A Transformer-Based Classification System for Volcanic Seismic Signals

Volcanic seismic signals are a key element in volcano monitoring to assess the state of unrest and a possible eruption style and timing. Different sources such as brittle fracture (volcano-tectonic - VT) or fluid movement (long period - LP) generate signals with distinct characteristics in frequency content and shape, but site effects such as attenuation or background noise make their determination difficult to the untrained eye. In cases of unrest or an eminent eruption, the amount of data would require a fast and reliable source of pre-classification to classify and catalogue to aid in the job usually done by a human. To model the problem, we will develop a custom-made Transformer model. Transformers are state-of-the-art deep learning methodologies that work with sequence-based data such as audio, text or, in this case, volcanic signals. The power of transformers lies in their ability to identify complex, disconnected patterns and then use them to identify phenomena in a very effective manner. We will be building the model architecture in TensorFlow and will be running them through SHARCNET. Unfiltered continuous data from seismic stations in Villarrica volcano will be used as train dataset and catalogued from at least these two types of events (VT and LP). The model will be then tested with a different set of stations to assess changes in the signal due to attenuation at the site. This will allow to discriminate the same event in different stations