Biblio

In this article, we study the transmission secrecy performance of primary user in overlay cognitive wireless networks, in which an untrusted energy-limited secondary cooperative user assists the primary transmission to exchange for the spectrum resource. In the network, the information can be simultaneously transmitted through the direct and relay links. For the enhancement of primary transmission security, a maximum ratio combining (MRC) scheme is utilized by the receiver to exploit the two copies of source information. For the security analysis, we firstly derive the tight lower bound expression for secrecy outage probability (SOP). Then, three asymptotic expressions for SOP are also expressed to further analyze the impacts of the transmit power and the location of secondary cooperative node on the primary user information security. The findings show that the primary user information secrecy performance enhances with the improvement of transmit power. Moreover, the smaller the distance between the secondary node and the destination, the better the primary secrecy performance.

The aim of the study is to evaluate the consistency of supplier risk assessment performed during the supplier selection process. Existing literature indicates that current supplier selection processes yield inconsistent results. Consistent supplier selection cannot be accomplished without stable risk assessment performed during the process. A case study was conducted in a train manufacturer in South Africa, and document analysis, interviews and questionnaires were employed to source information and data. Triangulation and pattern matching enabled a comparative study between literature and practice from which findings were derived. The study suggests selection criteria that may be considered when performing supplier risk assessment during the selection process. The findings indicate that structured supplier risk assessment with predefined supplier selection criteria may eliminate inconsistencies in supplier assessment and selection.