Advanced Materials Research Vols. 108-111

Abstract: This paper presents the introduction of late join problem in collaborative pattern design systems under the ubiquitous environment, describes the performance requirements that the algorithm should meet, and proposes an efficient multiple servers algorithm which can prevent the problem brought by single server algorithm. By using this algorithm, the problem of late join brought in collaborative design in the distributed environment is well solved.

Abstract: To improve the security and applicable capability of the group key management in 802.16e standard, the traditional group key management mechanism is discussed and the current security owing to lack of considering comprehensive factors, some security solutions designed also bring some problems. To solve these issues, Current multi-hop Wimax group key management security solutions were described firstly, then One-way Function Tree group key management mechanism is analyzed; An efficient group key management scheme based on one-way function is proposed, which can be used in multi-hop Wimax network system to enhance the security of group management effectively. Analysis result shows that, compared with the methods of One-way Function Tree, he proposed scheme has better performance in key storage, key updating and key calculation cost, which provides an effective solution for group key management in Wimax network and has better application value.

Abstract: Recently, several one time password authentication schemes have been proposed. However, most one-time password authentication schemes have security flaws. In this paper, a novel one-time password authentication and key agreement scheme (EAKAS) based on elliptic curve digital signature chain is developed. The proposed scheme has the following merits password or verification table is not required in the server; users can choose or change password; it can resist off-line dictionary attacks and achieves mutual authentication; it has no system clock synchronization and no constraint of transmission delay; it can resist replay attacks, man-in-the-middle attack and insider attack; it is sensitive to password error and strong in security restoration; the session keys in proposed scheme have the feature of freshness, confidentiality, known key security and forward security. Compared with the related schemes, our proposed scheme has better security and well suited to scenarios requiring a high level security.

Abstract: In directed diffusion (DD), the diffusion of interest and exploratory data leads to heavy energy consumption. In this paper, we propose an improved directed diffusion routing protocol on the basis of Passive Clustering Directed Diffusion (PCDD). This protocol has many merits:1).In order to avoid the unbalance energy consumption, this protocol adopts cluster declaration mechanism based on energy threshold value and gateway selection mechanism based on residual energy.2).In order to reduce the energy consumption of the network topology reconfiguration， this protocol uses the cluster head or gateway re-election algorithm in network topology maintenance mechanism. Compared with the related works through simulation, the proposed protocol can improve the energy efficiency of the network. Besides, the protocol obtains a better performance of end to end delay. Moreover, it has higher average packet delivery ratio.

Abstract: Take example for the Neural Networks Distinguishing Chemical Agents (NNDCA) model, the study and application about the multi-sensors information fusion (MSIF) technology is researched, the model of Naval Ships Chemical Detection (NSCD) system based on multi-sensors fusion is built, the basic method of the NNDCA is analyzed, and the realization idea of the NNDCA model is put forward. For fastness and accuracy and automation, connecting the wavelet analysis with the neural networks organically, the model of the NNDCA by the returning neural networks with deviation unit and the method of the feature extraction for the chemical agents based on the wavelet analysis are established. After analyzing and discussing the results a conclusion is drawn that it is a kind of valid method to realize the automation and intelligence of distinguishing chemical agents using the neural networks combined with the multi-sensors.

Abstract: Take example for the fault diagnostic system for shipboard chemical defense equipment, it is developed, applied virtual instrument technology, grey system theory, and database, in order to update entirely the means of the equipment testing. The modularization and universalization are proposed in its database-based design concept, realizing the design of software and hardware. The ODBC technique is applied for the interconnection of databases to ensure the generality and flexibility of the system. The system mode the best of virtual instrument platform and grey diagnosis method, broke through conventional check diagnosis patterns for warships chemical defense equipment, solved the problems of state prediction and trouble-mode recognition of warships chemical defense equipment. It has been proved by experiments that the system has merits both high accuracy and economical practicability. Also it can reduce the application development cycle and cost.