Self-Configuration and Self-Optimization Process in Heterogeneous Wireless Networks

Self-organization in Wireless Mesh Networks (WMN) is an emergent research area, which is becoming important due to the increasing number of nodes in a network. Consequently, the manual configuration of nodes is either impossible or highly costly. So it is desirable for the nodes to be able to configure themselves. In this paper, we propose an alternative architecture for self-organization of WMN based on Optimized Link State Routing Protocol (OLSR) and the ad hoc on demand distance vector (AODV) routing protocols as well as using the technology of software agents. We argue that the proposed self-optimization and self-configuration modules increase the throughput of network, reduces delay transmission and network load, decreases the traffic of HELLO messages according to network’s scalability. By simulation analysis, we conclude that the self-optimization and self-configuration mechanisms can significantly improve the performance of OLSR and AODV protocols in comparison to the baseline protocols analyzed

A survey on probabilistic broadcast schemes for wireless ad hoc networks

Broadcast or flooding is a dissemination technique of paramount importance in wireless ad hoc networks. The broadcast scheme is widely used within routing protocols by a wide range of wireless ad hoc networks such as mobile ad hoc networks, vehicular ad hoc networks, and wireless sensor networks, and used to spread emergency messages in critical scenarios after a disaster scenario and/or an accidents. As the type broadcast scheme used plays an important role in the performance of the network, it has to be selected carefully. Though several types of broadcast schemes have been proposed, probabilistic broadcast schemes have been demonstrated to be suitable schemes for wireless ad hoc networks due to a range of benefits offered by them such as low overhead, balanced energy consumption, and robustness against failures and mobility of nodes. In the last decade, many probabilistic broadcast schemes have been proposed by researchers. In addition to reviewing the main features of the probabilistic schemes found in the literature, we also present a classification of the probabilistic schemes, an exhaustive review of the evaluation methodology including their performance metrics, types of network simulators, their comparisons, and present some examples of real implementations, in this paper

Late results (up to 18 years) after parietal cell vagotomy

One hundred and two selected patients treated for duodenal ulcer disease by parietal cell vagotomy between 1975 and 1984, at the Department of Surgery of the Aegean University Faculty of Medicine were followed up for 1 to 18 years. The main indication for surgery was intractable pain (87%). A drainage procedure was employed in 12 patients, early in the study. During the first 10 years after parietal cell vagotomy (median follow-up 35 months), Visik 1+2 patients amounted to 82% of the series. There were five recurrences (5%) and 14% Visik 3 patients. Thirty-nine patients (38.6%) were lost for follow-up within the first 10 years of their operation. Among the 62 patients with 11 to 18 years follow-up (median follow-up 14 years), Visik 1+2 patients were 85%. The estimated cumulative recurrence rate was 9.8% for the entire series