Probabilistic flooding for efficient information dissemination in random graph topologies

Probabilistic flooding has been frequently considered as a suitable dissemination information approach for limiting the large message overhead associated with traditional (full) flooding approaches that are used to disseminate globally information in unstructured peer-to-peer and other networks. A key challenge in using probabilistic flooding is the determination of the forwarding probability so that global network outreach is achieved while keeping the message overhead as low as possible. In this paper, by showing that a probabilistic flooding network, generated by applying probabilistic flooding to a connected random graph network, can be (asymptotically) "bounded" by properly parameterized random graph networks and by invoking random graph theory results, asymptotic values of the forwarding probability are derived guaranteeing (probabilistically) successful coverage, while significantly reducing the message overhead with respect to traditional flooding. Asymptotic expressions with respect to the average number of messages and the average time required to complete network coverage are also derived, illustrating the benefits of the properly parameterized probabilistic flooding scheme. Simulation results support the claims and expectations of the analytical results and reveal certain aspects of probabilistic flooding not covered by the analysis. © 2009 Elsevier B.V. All rights reserved

Replicated random walks for service advertising in unstructured environments

Service advertisement is a key design issue in modern dynamic and largescale networking environments such as unstructured peer-to-peer networks. The intrinsic capability of a single random walker of stretching the information dissemination over widely spread network areas (compared to flooding), is explored and exploited in this paper, along with the introduction of random walkers which can replicate themselves. Two replication policies are also introduced in this paper: the Topology Independent Policy that creates replicas according to an exponentially decreasing probability (creating more replicas at the beginning of the advertising process), and the Topology Dependent Policy in which replication decisions are based on some locally available topological information (aiming at creating replicas at the dense network areas). The discussion and the results in this paper reveal intrinsic comparative properties of flooding and the single random walker, as well as the advantages that the random walker replication can bring in improving the overhead, speed and coverage of the advertising process. © 2008 International Federation for Information Processing

Energy cluster analysis based on consumption data in different weather condition

The main aim of this effort is the discovery of knowledge from data, concerning consumption of electric energy, during the year 2022, based on unattended learning methods. These data were collected from the Public Electricity Company of Kavala and the methods used are, at first the Factor analysis and second the K-means clustering algorithm. The overhead methodologies are realized by the use of Statistica Data Miner software

Multiple and replicated random walkers analysis for service discovery in fog computing IoT environments

The multiple random walkers mechanism is revisited in this paper for service discovery purposes considering modern dynamic network environments like the Internet of Things (IoT), where there is a need for certain services (e.g., virtual network functions) to be available to the end users through fog computing devices. Network coverage is analytically investigated here considering multiple random walkers in soft random geometric graph topologies of various densities. It is shown that as the number of random walkers increases, then coverage linearly increases in the considered topologies. The analytical findings of this work are shown to be in accordance with other results in the literature (e.g., coverage under multiple random walkers for fully connected network topologies). Moreover, for certain coverage and time constraints (i.e., the minimum fraction of network nodes to be covered within a certain time period that is of practical importance in the considered environment), the required minimum number of random walkers satisfying these constraints is also analytically derived. A replication mechanism that allows random walkers to replicate themselves after a fixed number of time steps is also analytically investigated here with respect to coverage for various topology densities. Simulation results demonstrate the effectiveness of multiple random walkers for service discovery purposes in the considered fog computing IoT environment and support the claims and expectations of the analysis for both the multiple random walkers and the replicated multiple random walkers mechanism. © 2019 Elsevier B.V

Study of Insulin Resistance, TNF-alpha, Total Antioxidant Capacity and Lipid Profile in Patients with Chronic Heart Failure under Exercise

Gluco-metabolic syndrome, oxidative stress and inflammation are common in chronic heart failure (CHF). Exercise training programmes are known to improve oxidative status, insulin sensitivity and endothelial function. In this study, the effects of walking on improving lipid and glucose metabolism in CHF patients, under statin treatment, were investigated. Fasting glucose, serum insulin, tumor necrosis factor-alpha (TNF-alpha), total antioxidant capacity (TAC), uric acid (UA), total cholesterol, triglycerides, high-density lipoproteins (HDL), direct low-density lipoproteins (LDL-dir), apolipoprotein-B, apolipoprotein-A1, and lipoprotein-a (Lp(a)) were monitored. Insulin resistance was depicted by fasting insulin resistance index (FIRI >= 2.94 +/- 1.41). HDL significantly increased with walking and was positively correlated with the non-significant triglyceride decrease and significant Lp(a) decrease. Significant correlations were found in all CHF patients at baseline between FIRI and New York Heart Association (NYHA) functional class, ejection fraction, HDL, triglycerides and TNF-alpha. All non-diabetic CHF patients were characterized by insulin resistance. Serum insulin and fasting glucose significantly decreased with walking, while decrease in FIRI was positively associated with patients' adherence to the walking program. Elevated uric acid and TNF-alpha levels also significantly decreased. In conclusion, the present study demonstrated that moderate, unsupervised, everyday physical activity was able to ameliorate the lipid and glycemic profile of CHF patients, with simultaneous attenuation of inflammation and oxidative stress