Special Section on Autonomic and Opportunistic Communications

It is our great pleasure to introduce this Special Section of the Journal, focused on Autonomic and Opportunistic Communications. We strongly believe autonomic and opportunistic properties will be a key feature of the Future Mobile Internet. The huge proliferation of mobile devices with wireless networking capabilities makes it possible to foresee a Future Internet environment in which users\u27 mobile devices will spontaneously network together and build self-organizing wireless networks for enabling users interaction and content exchange. This will be a natural enabler for the take off of User Generated Content and other user-centred networking models in the area of pervasive mobile networks

Impact of drone route geometry on information collection in wireless sensor networks

The recent technological evolution of drones along with the constantly growing maturity of its commercialization, has led to the emergence of novel drone-based applications within the field of wireless sensor networks for information collection purposes. In such settings, especially when deployed in outdoor environments with limited external control, energy consumption and robustness are challenging problems for the system’s operation. In the present paper, a drone-assisted wireless sensor network is studied, the aim being to coordinate the routing of information (among the ground nodes and its propagation to the drone), investigating several drone trajectories or route shapes and examining their impact on information collection (the aim being to minimize transmissions and consequently, energy consumption). The main contribution lies on the proposed algorithms that coordinate the communication between (terrestrial) sensor nodes and the drone that may follow different route shapes. It is shown through simulations using soft random geometric graphs that the number of transmitted messages for each drone route shape depends on the rotational symmetry around the center of each shape. An interesting result is that the higher the order of symmetry, the lower the number of transmitted messages for data collection. Contrary, for those cases that the order of symmetry is the same, even for different route shapes, similar number of messages is transmitted. In addition to the simulation results, an experimental demonstration, using spatial data from grit bin locations, further validates the proposed solution under real-world conditions, demonstrating the applicability of the proposed approach.publishedVersio

Stability Properties of 1-Dimensional Hamiltonian Lattices with Non-analytic Potentials

We investigate the local and global dynamics of two 1-Dimensional (1D) Hamiltonian lattices whose inter-particle forces are derived from non-analytic potentials. In particular, we study the dynamics of a model governed by a "graphene-type" force law and one inspired by Hollomon's law describing "work-hardening" effects in certain elastic materials. Our main aim is to show that, although similarities with the analytic case exist, some of the local and global stability properties of non-analytic potentials are very different than those encountered in systems with polynomial interactions, as in the case of 1D Fermi-Pasta-Ulam-Tsingou (FPUT) lattices. Our approach is to study the motion in the neighborhood of simple periodic orbits representing continuations of normal modes of the corresponding linear system, as the number of particles $N$ and the total energy $E$ are increased. We find that the graphene-type model is remarkably stable up to escape energy levels where breakdown is expected, while the Hollomon lattice never breaks, yet is unstable at low energies and only attains stability at energies where the harmonic force becomes dominant. We suggest that, since our results hold for large $N$, it would be interesting to study analogous phenomena in the continuum limit where 1D lattices become strings.Comment: Accepted for publication in the International Journal of Bifurcation and Chao

Ενοποιημένη πρόσβαση στις πηγές των βιβλιοθηκών

Nowadays, libraries contain material deriving from various electronic resources and in different formats. The fact that libraries provide information from different resources has brought up several difficulties regarding the organization and the dissemination of such material to the end-users, such as information research and retrieval in separate services and in different graphical user interfaces. In order to confront such difficulties, libraries started to focus on digital technologies, which provide tools and techniques for the formation and the creation of software that can help end-users in information search and retrieval process. In these lines of thought, tools that provide federated search functionality for the library services were created

Recurrent Jarisch-Herxheimer reaction in a patient with Q fever pneumonia: a case report

Q fever is a zoonotic disease caused by coxiella burnetii. The Jarisch-Herxheimer reaction (JHR) is associated with the antibiotic treatment of certain bacterial infections. We report a very rare case of a 36-year-old male with Q fever pneumonia that resulted in recurrent ARDS and presented the JHR during his treatment. The patient was admitted for treatment of community acquired pneumonia. He developed ARDS, was intubated and placed on mechanical ventilation. Doxycycline was empirically added to his antibiotic regiment. The patient presented an acute rise in temperature, tachycardia, tachypnea, hypoxia, hypotension and a temporary deterioration of his chest x-ray. The same 6-hour-long reaction which is known as JHR was presented another 3 times. Cultures were negative but antibodies against coxiella burnetii were positive. This case reminds us that any deterioration of a patient treated in the ICU should not be considered as a new septic episode and time should be allowed for the antibiotic regiments

Acute renal failure and rhabdomyolysis in a patient with infectious mononucleosis: a case report

We report a very rare case of acute renal failure and rhabdomyolysis in an Intensive Care treated 20-years-old male with upper airway obstruction due to Epstein-Barr infection. In our opinion this was a manifestation of the very rare and potentially lethal propofol infusion syndrome and not a direct complication of the underlying infection, although renal biopsy was not performed in our patient

Transcatheter Bioprosthetic Aortic Valve Durability: Where do we Stand?

Transcatheter aortic valve implantation (TAVI) was initially reserved for inoperable or high surgical risk patients with severe symptomatic aortic valve stenosis, but after the recent publication of randomized studies comparing TAVI to surgical aortic valve replacement (AVR) among intermediate risk (PARTNER 2 and SURTAVI) and low risk patients (PARTNER 3 and Evolut Low Risk), the momentum for further expansion of TAVI at the expense of AVR seems irreversible. The main obstacle before the wider application of TAVI for intermediate and lower risk patients is the uncertainty regarding bioprosthetic valve durability and the potential for structural deterioration and dysfunction over time. A concise overview regarding bioprosthetic valve durability issues, the relevant current scientific data and their importance for TAVI patient selection and management is herein presented. Rhythmos 2020;15(1):72-76

Intrapelvic migration of the hip screw of a proximal femoral nail: report of two cases and review of the literature

Two cases of medial migration of the hip screw in cases of cephalon-medullary nailing for the treatment of extra-articular proximal femoral fractures are reported. The first case was revised to hemiarthroplasty, that was subsequently complicated with infection and death of the patient, while the second was revised to a similar devise with favorable outcome. A review of the literature is performed in order to identify the contributing factors that result in the medial migration of the hip screw. Emphasis is given in further reporting of similar cases in order to abolish this potentially lethal complication.