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This paper presents a new steady-state productivity equation for horizontal wells in gas reservoirs with upper and lower boundary enclosed. Firstly, the fundamental solution to the 3-D steady-state Laplace equation is derived with the philosophy of source and the Green function for a horizontal well located at the center of the laterally infinite gas reservoir, with considering the above boundaries conditions. Then, using the fundamental solution and the Simpson integral formula, the average pseudo-pressure equation and the steady-state productivity equation are achieved for the horizontal section. Case-studies are given in the paper, and the results calculated from the newly-derived formula are very close to the numerical simulation performed with the Canadian software CMG and the real production data, indicating that the new formula can be used to predict the steady-state productivity of such horizontal gas wells.

Aiming at the problem on lack of independence and interoperability between Virtual Enterprise members in the process of interactive authentication, a virtual certificate authority model is constructed based on the (t ,n) threshold theory and mobile agent technology. Using of the autonomy, heterogeneity, dynamic, mobility and interoperability of the agent technology, several protocols of VCA are designed, such as creation protocol of the VCA, issuance protocol of member certificates and authentication protocol of members, etc. By testing, the system can meet the needs of threshold interactive authentication. The interactive authentication between member enterprises can be implemented.

A novel algorithm called Free Search (FS) is applied to solve the scheduling problems on a single batch processing machine with non-identical job sizes (NSBM) in this paper. The concept of sensibility was introduced in FS, with which the algorithm had norestriction of the probability to zero for the parts of the search space and thus it could avoid premature convergence. In order to make it feasible to NSBM problem, we modify the parameters settings and also provide coding by vector method which makes FS proper to discrete problem. Then the algorithm of batching based FS (BFS) is proposed. In the experiment, all levels of instances are simulated and the results show that BFS has better performance on global search and outperforms other algorithm in the literature.

Collaborative design is one of core processes for networked manufacturing, so how to safely transfer design information in the network has important significance. In order to provide the confidentiality of transmission information on the level of design team in collaborative design system, a new broadcast encryption scheme based on designer’s identity is presented. The new scheme is based on broadcast encryption theory. By introducing master key of design teams and distributing the public and secret parameters reasonably, every designer can encrypt design documents and transmit them expediently. The encrypted document can be decrypted only by the members of the designated design team. In the new scheme the private key escrow problem of ID-based public key system is solved. Analysis shows that the new scheme is secure under the discrete logarithm assumption and users out of the designated design team can’t decrypt the documents. The new scheme can be used in the collaborative design system to protect the security of design information.

Network anomaly detection technology has been the research hotspot in intrusion detection (ID) field for many years. However, some issues like high false alarm rate, low detection rate and limited types of attacks which can be detected are still in existence so its wide applications in practice has been restricted. A new network anomaly detection method has been proposed in this paper. The main idea of the method is network traffic is analyzed and estimated by using Relative Entropy Theory (RET), and a network anomaly detection model based on RET is designed as well. The numerical value of relative entropy is used to alleviate the inherent contradictions between improving detection rate and reducing false alarm rate, which is more precise and can effectively reduce the error of estimation. On the 1999 DARPA/Lincoln Laboratory IDS evaluation data set, the detection results showed that the method can reach a higher detection rate at the premise of low false alarm rate.

Designated verifier signature (DVS) does not provide non-repudiation property of traditional digital signatures. Multi-signers strong designated verifier signature (MS-SDVS) scheme is required in some cases for the privacy consideration. In this paper the definition and security model of MS-SDVS scheme are presented, and a concrete MS-SDVS scheme is proposed from bilinear pairing. The proposed scheme has the property of non-transferability and unforgeability in the random oracle model under the assumption of the bilinear computational Diffie-Hellman problem (BCDH). This is the first MS-SDVS scheme. The signature length of the proposed scheme is independent of the number of signers, and the proposed scheme can be modified to a multi-signature scheme.