Consensus based optimization with memory effects: random selection and applications

In this work we extend the class of Consensus-Based Optimization (CBO) metaheuristic methods by considering memory effects and a random selection strategy. The proposed algorithm iteratively updates a population of particles according to a consensus dynamics inspired by social interactions among individuals. The consensus point is computed taking into account the past positions of all particles. While sharing features with the popular Particle Swarm Optimization (PSO) method, the exploratory behavior is fundamentally different and allows better control over the convergence of the particle system. We discuss some implementation aspects which lead to an increased efficiency while preserving the success rate in the optimization process. In particular, we show how employing a random selection strategy to discard particles during the computation improves the overall performance. Several benchmark problems and applications to image segmentation and Neural Networks training are used to validate and test the proposed method. A theoretical analysis allows to recover convergence guarantees under mild assumptions on the objective function. This is done by first approximating the particles evolution with a continuous-in-time dynamics, and then by taking the mean-field limit of such dynamics. Convergence to a global minimizer is finally proved at the mean-field level

Les défis de l'émulation Wi-Fi à base des traces

Wi-Fi link is unpredictable and it has never been easy to measure it perfectly; there is always bound to be some bias. As wireless becomes the medium of choice, it is useful to capture Wi-Fi traces in order to evaluate, tune, and adapt the different applications and protocols. Several methods have been used for the purpose of experimenting with different wireless conditions: simulation, experimentation, and trace-driven emulation. In this paper, we argue that trace-driven emulation is the most favourable approach. In the absence of a trace-driven emulation tool for Wi-Fi, we evaluate the state-of-the-art trace driven emulation tool for Cellular networks and we identify issues for Wi-Fi: interference with concurrent traffic, interference with its own traffic if measurements are done on both uplink and downlink simultaneously , and packet loss. We provide a solid argument as to why this tool falls short from effectively capturing Wi-Fi traces. The outcome of our analysis guides us to propose a number of suggestions on how the existing tool can be tweaked to accurately capture Wi-Fi traces.La liaison Wi-Fi est imprévisible et il n'a jamais été facile de la mesurer parfaitement ; il y a toujours un risque de biais. Comme le sans fil devient le moyen de communication de choix, il est utile de capturer les traces Wi-Fi afin d'évaluer, de régler et d'adapter les différentes applications et protocoles. Plusieurs méthodes ont été utilisées pour expérimenter différentes conditions sans fil : la simulation, l'expérimentation et l'émulation de traces. Dans cet article, nous soutenons que l'émulation pilotée par les traces est l'approche la plus favorable. En l'absence d'un outil d'émulation piloté par trace pour le Wi-Fi, nous évaluons l'outil d'émulation piloté par trace de pointe pour les réseaux cellulaires et nous identifions les problèmes pour le Wi-Fi : interférence avec le trafic concurrent, interférence avec son propre trafic si les mesures sont effectuées simultanément sur la liaison montante et la liaison descendante, et perte de paquets. Nous fournissons un argument solide pour expliquer pourquoi cet outil ne parvient pas à capturer efficacement les traces Wi-Fi. Le résultat de notre analyse nous guide pour proposer un certain nombre de suggestions sur la manière dont l'outil existant peut être modifié pour capturer avec précision les traces Wi-Fi

Efficacy of ozonated water as a PS in photodynamic therapy: A tool for dental caries management? An in vitro study

Background: The most prevalent noncommunicable disease in the world is dental caries; and when it is not adequately treated, it is usually associated with tooth loss or severe dental lesions. In fact, expensive care or tooth extraction may be necessary due to the negative effects dental caries have on general health. This is due to its frequent pain and secondary bacterial infections. The aim of this study was to investigate the activity of ozonated water as such and in combination with appropriate light radiation so as to perform a photodynamic treatment (PDT) against the cariogenic bacterium Streptococcus mutans. Design and methods: This work has been performed in vitro by using an S. mutans strain mainly structured in a biofilm status, reproducing the natural condition of the tooth infection. The ozone was tested at three different concentrations by using a commercial device able to generate different O3 formulations in water. The PDT treatment requires an appropriate light wavelength, evaluated in this work through the UV-Vis adsorption spectrum of the ozonated water. Results: The obtained results suggested an effective and synergic property of O3 and light at 460–470nm against this microorganism. The most antibiofilm activity was observed using a concentration of ozone of 0.06mg/L alone as well as with PDT treatment. Conclusions: The results are encouraging for additional research and in vitro/in vivo fresh experimental investigations to perform an exhaustive antimicrobial treatment protocol against the S. mutans tooth infection

Case Report: Cetuximab use in advanced cutaneous squamous cell carcinoma resistant to chemotherapy

We present the case of a 60-year-old man with unresectable cutaneous squamous cell carcinoma (cSCC) of the sternal area, which was not amenable to radiation therapy. The treatment history of this patient is remarkable as the disease had progressed through all lines of conventional therapy established in the literature. We decided to initiate treatment with epidermal growth factor receptor (EGFR) inhibitor cetuximab and we reassessed the patient after 12 weeks with a whole-body CT scan, documenting stability in the size and radiologic features of the disease. Cetuximab, like all current treatments for advanced cSCC, is administered off-label and proved effective in preventing further progression of disease in our patient

Mouthwash Based on Ozonated Olive Oil in Caries Prevention: A Preliminary In-Vitro Study

(1) Background: Ozone (O3) proved to oxidize organic and inorganic compounds, and its efficacy against bacteria, viruses and fungi plasma membranes was of interest. Ozone vehicle can be a gaseous form, ozonated water or ozonized oil. The aim of this in-vitro study was to evaluate the efficacy of ozonated olive oil against Streptococcus mutans. (2) Methods: Two different commercial mouthwashes were tested: Ialozon Blu (IB) (Gemavip, Cagliari, Italy), with ozonated olive oil, and Ialozon Rose (IR) (Gemavip, Cagliari, Italy), with ozonated olive oil, hyaluronic acid and vitamin E. All formulates were analyzed in a dilution range from 2- to 256-folds in saline solution, as to reproduce the salivary dilution. Streptococcus mutans CIP103220 strain was used for the antimicrobial susceptibility test, and the Kirby-Bauer inhibition method was performed to evaluate the Minimum Inhibitory (MIC), Minimum Bactericidal (MBC), and Minimum Biofilm Inhibitory Concentration (MBIC). (3) Results: Both formulates showed the same antimicrobial activity. MIC, MBC, and MBIC were observed for dilution factors of 1/32, 1/8 and 1/8, respectively. The mean value of inhibition zone diameter was 16.5 mm for IB, and 18 mm for IR. (4) Conclusions: The results suggested that ozonized olive oil formulates were able to inactivate Streptococcus mutans avoiding the salivary dilution effect in the oral cavity