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A mobile ad hoc network is a group of wireless mobile nodes with a self-organizing system. A malicious node exhibits some unusual behavior, like sending bogus RREQs to generate sinkhole attacks. In this paper, we have presented a hybrid mechanism with three phases that are following: sinkhole indicator, detection and isolation. First, our approach finds the path where the sinkhole node is located on it. Then, the node that detects the existence of the sinkhole node will probe the other nodes to detect if any of them fail to perform the forwarding function. The proposed algorithm has lower overhead and higher time detection than other described algorithms in this paper.

Abstract-To increase efficiency, speed, accuracy and to decrease cost, the recent approaches in developing decision support systems for agriculture, and more generally for environmental problems management, tend to adopt a "systemic" approach. This paper presents a new methodology for mechanization of mushroom cultivation which can be applied to other agricultural products. We are using a multi-agent system to parallelize most of mechanization steps which can considerably increase the speed and efficiency of cultivation or production. This system consists of six agents, namely, Monitoring of environmental condition, Preparation of Compost, Day counter, Temperature regulator, Sprinkler and Harvest. The paper provides a review on the studies on mechanization with multi-agent and the other methods, the multi-agent model, functionality of each agent, the overall efficiency of this methodology and compares it with some other existing works.

This article has presented a Structural cryptanalysis on MRVLK (Message Based Random Variable Length Key Encryption). In this cipher, key length is started from small amount of bits and then will be grown in size. The cipher has variable rounds, random bitwise rotations and dynamic key length that provide resistance to linear and differential cryptanalysis. In spite of these advantages, some disadvantages are observed such as correlation between the ciphertexts in each stage which facilitates structural attack. Even random mechanism such as S-box in this cipher cannot prevent this attack. The attack performs analysis on the final ciphertext and reveals the plaintext of MRVLK by exploiting the fact that the structure of the ciphertext is obvious and weak. The presented attack efficiently utilizes this information and prompts the operations cryptanalysis. Performance of this attack is evaluated in terms of running time. The results show that the original plaintext is achievable to minimal cost.