As the demand increases for the use Unmanned Aerial Vehicles (UAVs) to monitor natural disasters, protecting territories, spraying, vigilance in urban areas, etc., detecting safe landing zones becomes a new area that has gained interest. This paper presents an intelligent system for detecting regions to navigate a UAV when it requires an emergency landing due to technical causes. The proposed system explores the fact that safe regions in images have flat surfaces, which are extracted using the Gabor Transform. This results in images of different orientations. The proposed system then performs histogram operations on different Gabor-oriented images to select pixels that contribute to the highest peak, as Candidate Pixels (CP), for the respective Gabor-oriented images. Next, to group candidate pixels as one region, we explore Markov Chain Codes (MCCs), which estimate the probability of pixels being classified as candidates with neighboring pixels. This process results in Candidate Regions (CRs) detection. For each image of the respective Gabor orientation, including CRs, the proposed system finds a candidate region that has the highest area and considers it as a reference. We then estimate the degree of similarity between the reference CR with corresponding CRs in the respective Gabor-oriented images using a Chi square distance measure. Furthermore, the proposed system chooses the CR which gives the highest similarity to the reference CR to fuse with that reference, which results in the establishment of safe landing zones for the UAV. Experimental results on images from different situations for safe landing detection show that the proposed system outperforms the existing systems. Furthermore, experimental results on relative success rates for different emergency conditions of UAVs show that the proposed intelligent system is effective and useful compared to the existing UAV safe landing systems.

Transport Layer Security (TLS) is the most popular security protocol of the transport layer. It is widely used to provide basic security services of authentication, confidentiality, and integrity of sensitive data. It is carried out in critical untrusted networks between client and server entities, such as e‐commerce and online transactions. Despite multiple capabilities, TLS protocol is vulnerable to the malicious server attacks that may cause a serious threat to TLS‐based e‐commerce communications. This should be considered as the first problem of this protocol. The other problem of TLS is sending many messages during the handshake phase for providing a successful negotiation and a secure communication. So, this phase is the most complex and time‐consuming phase of the TLS protocol. This causes decreasing of service capacity and using more time. We are going to propose a new protocol based on trust model called “TSSL protocol” in this paper. This model is used to conquer the disadvantages with security of the TLS protocol. Through this paper, it is going to be indicated that the proposed model has higher levels in both security and performance compared with the conventional TLS. Copyright © 2014 John Wiley & Sons, Ltd.

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