A Decentralized Lifetime Maximization Algorithm for Distributed Applications in Wireless Sensor Networks

We consider the scenario of a Wireless Sensor Networks (WSN) where the nodes are equipped with a programmable middleware that allows for quickly deploying different applications running on top of it so as to follow the changing ambient needs. We then address the problem of finding the optimal deployment of the target applications in terms of network lifetime. We approach the problem considering every possible decomposition of an application's sensing and computing operations into tasks to be assigned to each infrastructure component. The contribution of energy consumption due to the energy cost of each task is then considered into local cost functions in each node, allowing us to evaluate the viability of the deployment solution. The proposed algorithm is based on an iterative and asynchronous local optimization of the task allocations between neighboring nodes that increases the network lifetime. Simulation results show that our framework leads to considerable energy saving with respect to both sink-oriented and cluster-oriented deployment approaches, particularly for networks with high node densities and non-uniform energy consumption or initial battery charge

Finite-Time Consensus with Disturbance Rejection by Discontinuous Local Interactions in Directed Graphs

In this technical note we propose a decentralized discontinuous interaction rule which allows to achieve consensus in a network of agents modeled by continuous-time first-order integrator dynamics affected by bounded disturbances. The topology of the network is described by a directed graph. The proposed discontinuous interaction rule is capable of rejecting the effects of the disturbances and achieving consensus after a finite transient time. An upper bound to the convergence time is explicitly derived in the technical note. Simulation results, referring to a network of coupled Kuramoto-like oscillators, are illustrated to corroborate the theoretical analysis

Dynamic Max-Consensus and Size Estimation of Anonymous Multi-Agent Networks

In this paper we propose a novel consensus protocol for discrete-time multi-agent systems (MAS), which solves the dynamic consensus problem on the max value, i.e., the dynamic max-consensus problem. In the dynamic max-consensus problem to each agent is fed a an exogenous reference signal, the objective of each agent is to estimate the instantaneous and time-varying value of the maximum among the signals fed to the network, by exploiting only local and anonymous interactions among the agents. The absolute and relative tracking error of the proposed distributed control protocol is theoretically characterized and is shown to be bounded and by tuning its parameters it is possible to trade-off convergence time for steady-state error. The dynamic Max-consensus algorithm is then applied to solve the distributed size estimation problem in a dynamic setting where the size of the network is time-varying during the execution of the estimation algorithm. Numerical simulations are provided to corroborate the theoretical analysis

Decentralized Estimation of Laplacian Eigenvalues in Multi-Agent Systems

In this paper we present a decentralized algorithm to estimate the eigenvalues of the Laplacian matrix that encodes the network topology of a multi-agent system. We consider network topologies modeled by undirected graphs. The basic idea is to provide a local interaction rule among agents so that their state trajectory is a linear combination of sinusoids oscillating only at frequencies function of the eigenvalues of the Laplacian matrix. In this way, the problem of decentralized estimation of the eigenvalues is mapped into a standard signal processing problem in which the unknowns are the finite number of frequencies at which the signal oscillates

Constrained Invariant Motions for Networked Multi-Agent Systems

© 2009 AACCDigital Object Identifier : 10.1109/ACC.2009.5160191In this paper we propose a methodology to solve the constrained consensus problem, i.e., the consensus problem for multi-agent systems with constrained dynamics. We propose a decentralized one-step horizon optimization problem to be solved iteratively by the agents to achieve rendezvous at the centroid of the network while ensuring the connectivity of the network and the feasibility of the agents motion respect to their constrained kinematics. We also provide simulations of the algorithm behavior

Patient's satisfaction after 2-piece inflatable penile prosthesis implantation: An Italian multicentric study.

Introduction: Penile prosthesis implant represents a valuable solution for pts with severe erectile dysfunction (ED), non-responders to medical management. The aim of our study was to evaluate the satisfaction of patients (pts) after 2-pieces inflatable penile prosthesis (IPP). Aim of the study: to evaluate safety, reliability and post-operative patient's satisfaction after implantation of two-pieces IPP. Materials and Methods: This retrospective multicentric analysis concerns a group of 42 patients undergone 2-pieces IPP implantation from November 2005 to November 2013, in four Centers of proven experience. As a first step, a detailed review of all clinical reports was performed. Secondly, every patient was asked to fill the Erectile Dysfunction Inventory of Treatment Satisfaction (EDITS) specifically modified, in order to assess their own satisfaction after surgery and, its impact on patient's quality of sexual life. Results: 42 pts were evaluated (AMS-Ambicor: 28; Coloplast- Excell: 14); mean age, at time of operation: 60,7 years; mean follow up: 27,6 months; etiology of ED: vascular 23,8%, diabetes 19%, La Peyronie D. 7,1%, consequence of radical prostatectomy 31%, consequence of other pelvic surgery 11,9%, spinal trauma 7%. Mean operative time: 117 ± 58 min, mean postoperative hospital stay 3 ± 1,6 days. Post operative short-term complications: 4 pts (9,5%). Post operative long-term complications: 4 pts (9,5%). Long-term functional results (Questionnaire): 71% of pts (30) reported regular use of the prosthesis, at least 1 time/week, the satisfaction was good in 42% of pts (18), quite good in 33,3% (14), quite bad in 2,4% (1), very bad in 7,1% (3), 6 pts (14,4%) didn't answer. Conclusions: 2 pieces IPP appears to be associated with a low complication rate and good satisfaction of pts especially in the elderly. It also assures satisfactory rates of aesthetics and functional results

Italian experiences in the management of andrological patients at the time of Coronavirus pandemic.

The SARS-CoV-2 (Severe acute respiratory syndrome coronavirus 2) was first reported in December 2019, then its rapid spread around the world caused a global pandemic in March 2020 recording a high death rate. The epicenter of the victims moved from Asia to Europe and then to the United States. In this Pandemic, the different governance mechanisms adopted by local health regional authorities made the difference in terms of contagiousness and mortality together with a community strong solidarity. This document analyzes the andrological urgencies management in public hospitals and in private practice observed in Italy and in particular in the most affected Italian Regions: Emilia-Romagna and Marche

Testis Sparing Surgery of Small Testicular Masses: Retrospective Analysis of a Multicenter Cohort

PURPOSE: We evaluated possible factors predicting testicular cancer in patients undergoing testis sparing surgery. MATERIALS AND METHODS: We retrospectively analyzed the records of all patients who underwent testis sparing surgery for a small testicular mass at a total of 5 centers. All patients with 1 solitary lesion 2 cm or less on preoperative ultrasound were enrolled in the study. Testis sparing surgery consisted of tumor enucleation for frozen section examination. Immediate radical orchiectomy was performed in all cases of malignancy at frozen section examination but otherwise the testes were spared. Univariate and multivariate analysis were performed and ROC curves were produced to evaluate preoperative factors predicting testicular cancer. RESULTS: Overall 147 patients were included in the study. No patient had elevated serum tumor markers. Overall 21 of the 147 men (14%) presented with testicular cancer. On multivariate analysis the preoperative ultrasound diameter of the lesion was a predictor of malignancy (OR 6.62, 95% CI 2.26-19.39, p=0.01). On ROC analysis lesion diameter had an AUC of 0.75 (95% CI 0.63-0.86, p=0.01) to predict testicular cancer. At the best cutoff of 0.85 the diameter of the lesion had 81% sensitivity, 58% specificity, 24% positive predictive value and 95% negative predictive value. CONCLUSIONS: Our study confirms that small testicular masses are often benign and do not always require radical orchiectomy. Preoperative ultrasound can assess lesion size and the smaller the nodule, the less likely that it is malignant. Therefore, we suggest a stepwise approach to small testicular masses, including tumorectomy, frozen section examination and radical orchiectomy or testis sparing surgery according to frozen section examination results