In peer-to-peer content distribution the lack of a central authority makes authentication difficult. Without authentication, adversary nodes can spoof identity and falsify messages in the overlay. This enables malicious nodes to launch man-in-the-middle or denial-of-service attacks. In this paper, we present a trust based content distribution for peer-to-peer overlay networks, which is built on...

Abstract Quaternary placer deposits are becoming increasingly important. Remote sensing is a very powerful tool in discriminating altered areas related to intrusion deposits, which has significantly reduced the cost and time of exploration. In this study, to identify iron-bearing alluvial zones within the 1:100000 sheet of Hamedan, satellite image processing techniques such as band ratio (BR),...

Hierarchical femtocellular architectures have become popular recently because of their potential to provide increased coverage and capacity in cellular systems. However, introduction of femtocells might reduce the overlay macrocellular system performance due to increased interference caused to macrocellular users. In this article, two MIMO precoding techniques are considered at the femtocellula...

Urban ecological vulnerability is measured on the basis of ecological sensitivity and resilience based on the concept analysis of vulnerability. GIS-based multicriteria decision analysis (GIS-MCDA) methods are used, supported by the spatial analysis tools of GIS, to define different levels of vulnerability for areas of the urban ecology. These areas are further classified into different types o...

One of the most widely known topological index is the Wiener index. The Wiener Index Conjecture states that all positive integer numbers except a finite set are the Wiener indices of some trees. We explore the Wiener indices of the binary trees. We present efficient algorithms for generating the Wiener indices of the binary trees. Based on experiments we strengthen the conjecture for the class ...

alveolar ridge is underdeveloped in ectodermal dysplasia (ed). the available treatment plans include fixed, removable or implant-supported prostheses, alone or in combination. a 5 year-old boy was referred for treatment to the department of prosthodontics, tehran university of medical sciences with the chief complaint of missing teeth. prosthodontic treatment was performed to improve masticatio...