Applied Mechanics and Materials Vols. 644-650

Abstract: Wireless sensor network works based on the clock synchronization, which need to eliminate hardware-induced drift as well as clock offset. This paper presents an Advanced Virtual Clock Synchronization protocol based on the index approximation.Each node accesses to the network with an unique clock drift and offset, the more difference between the node and the virtual clock, the fast the node adjusts it's drift and offset, thus improve the synchronization efficiency. Simulation data proves that this protocol can effectively improve the synchronization efficiency.

Abstract: In order to solve the problem of our country in the construction of agricultural information, such as a single mode of information services, guidance and applicability of the information is not enough and so on, research and design agricultural information service platform based on cross-platform Technology. The mobile terminal as the carrying platform and take advantage of its portability, the popularity and relatively low price, convenient on-site processing ability. The platform integrating agricultural information, agricultural policy, agricultural knowledge, agricultural pre-warning, characteristic agriculture, rich experience, experts inquiry in one, zero distance contact farmers and agricultural information, it has high practical value and broad application prospects.

Abstract: Mobile sensor networks (MSNs) have many applications in recent years, especially in some harsh environment, such as battlefield reconnaissance. MSNs may suffer from a large-scale damage which causes many nodes to fail and the network to get partitioned into isolate islands. So in order to avoid negative effects on the application, restoring network connectivity is crucial in such case. In this paper, we propose a novel method, CPANMCR, which combines power adjustment and node’s movement to restore the network connectivity. In CPANMCR mainly include three phases: firstly detecting the boundary nodes of every isolate island, then adjusting the power of boundary node to restore the connection, and finally moving mobile nodes to the appropriate location to restore the connectivity of the entire network. Extensive simulation experiments demonstrate that the proposed method can guarantee network connectivity and reduce the total travel distance.

Abstract: App pirate remains a serious threat to the emerging mobile app ecosystem, especially in the Android Market. In this paper, we propose an anti-piracy method based on encryption and dynamic loading for Android applications. The basic idea of the method is to separate dex file from the original apk file and encrypt it, then hidden the dex file into resource, finally use a shell dex file to replace the original dex file. When apk is installed, the shell dex file begins to run and release the oringinal dex file and dynamic loading into memory. Once loaded success, shell code start the original apk activity through startActivity. Android app developers can use this method to protect their apps and the method is simple and convenient.

Abstract: With the design teamdevelopment and the design data quality improvement, the problems in the process of design appear constantly, such as collaborative design, data security managementand dataremote processing.In order to solve these problems, we begin to research and implementation of design datamanagement andprocessing system (DDMP). The system adopts B/S architecture. Through online operations (accept task, review data, etc.), as well as strict management of the system data to realize long distance collaborative design. System respectively from the platform environment, data management, and user access control three aspects to ensure the safety of system. At last, DDMP integrates with rendering and 3D printing platform torealizeremoteprocessing ofdesign data.

Abstract: In this paper, a home wireless network platform based on Zigbee technology. This article analyzes the Zigbee network protocol, discusses the key issues to build a home wireless network using the Zigbee technology. The network topology, network routing algorithms and network sampling strategies and other issues were discussed and proposed solutions by building a home wireless network monitoring experiments on the pulse signal. The results showed that based on Zigbee technology to build a home wireless network is feasible, the wireless network in the home monitoring has broad application prospects.

Abstract: Webpage tampering prevention system is a security protection means of website to prevent from hacker’s unauthorized update to webpage. This paper deeply researches the key technology of webpage tampering prevention system, i.e., poll tampering detection technology, core embedding technology and file filtering drive technology, the algorithm of three prevailing tampering prevention detection technologies is realized on the basis of apache platform, they are integrated together to form an exclusive and perfect new type tampering prevention system.

Abstract: Excessive product reviews bring much inconvenient for users to obtain information. It will waste a lot of time, and these spam reviews will occupy much data traffic. Paper focuses on the design a fast filtering algorithm to filter out spam based on content and text length, only leave useful reviews to readers. It can help users to quickly view the more valuable and useful product reviews information, help users understand product information, and facilitate electronic transactions.

Abstract: This paper analyzes several kinds of S/KEY One-time Password (OTP) identity authentication schemes, and designs a new OTP identity authentication scheme with the increasing hash chains. The new scheme overcomes the weakness of common OTP schemes which need to reset parameters when used, consequently reduces the sever burden, and does not need any kinds of assists provided by additional hardware or serves. Furthermore, it can realize the client - server authentication and resist the common network attacks.

Abstract: The key-stream generator is the most important algorithm component of the stream cipher and the security of the stream cipher is based on the property of the key-stream generator. At the present, it is still an important development direction of the stream cipher algorithm that the high performance key-stream generators are constructed with complex block cipher algorithms. This paper puts forward the new type of the key-stream generator based on the AES algorithm. This method is based on the OFB mode of the AES algorithm, combined with the variable-step feedback shift. Then the paper analyses the randomness of the key-stream produced by the new key-stream generator. This new key-stream generator really improves the cryptographic properties of the key stream generator and to enhance the security of stream cipher effectively.