Dual Image Reversible Data Hiding by Modifying Least Significant-Bit Matching Revisited Rules

The concept of dual image reversible data hiding（DIRDH） is the technique that can produce two camouflage images after embedding secret data into one original image.Moreover,not only can the secret data be extracted from two camouflage images but also the original image can be recovered.To achieve high image quality,Lu et al.＇s method applied least-significant-bit（LSB） matching revisited to DIRDH.In order to further improve the image quality,the proposed method modifies LSB matching revisited rules and applies them to DIRDH.According to the experimental results,the image quality of the proposed method is better than that of Lu et al.＇s method.

Dual Authentication Hashing for Security Enhancement in MANET

Mobile Ad hoc Network (MANET) is a collection of mobile hosts with wireless interfaces that form a temporary network without the aid of any fixed infrastructure or centralized administration. A MANET is a type of ad hoc network that can change locations and configure itself on the fly. The dynamic and cooperative behaviour of ad hoc networking without any centralized or unified controlling authority for authentication and monitoring is sensitive to attacks that damage or exploit the cooperative behaviour of ad hoc routing. Routing attacks lead to the most disastrous damage in MANET. The main objective of this paper is to enhance the security against routing attacks in MANETs. Intrusion detection based on DAHT (Dual Authentication Hash Technique) entirely depends on the end to end communication between the source and destination is employed here. The proposed technique identifies the misbehaving nature of current node and the previous node where it receives the information. DAHT is simulated with various parameters in NS2. The results obtained are compared with existing mechanism. The results show that malicious detection, overhead reduction and delay are better when compared to the existing system that is employed in protecting the routing information.

A cased-hole acoustic logging technique using the dual source of opposite polarity

It is usually difficult to measure acoustic velocities through a casing, especially when the casing is poorly bonded with formation. An acoustic logging technique using the dual source of opposite polarity is proposed to enhance the Signal to Noise Ratio of the formation signal and to reduce the casing wave in the data acquisition process. In what follows, a theoret- ical modeling is used to caculate the wavefroms of cased wells. And then, a scaled experiment was conducted in the 1：10 scaled experimental well using the proposed technique in the poorly- bonded condition. The results show that this technique can effectively suppress the casing wave and enhance the formation wave, even in the poorly-bonded condition. By analyzing the measured wavefroms, the amplitude of casing wave is reduced to 12% compared to the conventional one-source technique, and the compressional wave velocity can be easily obtained by using this technique. Both the theoretical modeling and experiment results demonstrate the feasibility of the proposed technique. This study establishes the theoretical and experimental foundation for the cased-hole, dual source of opposite polarity, acoustic logging tool development.