Dimethyl sulfide (DMS) is a key compound in global sulfur and carbon cycles. DMS oxidation products cause cloud nucleation and may affect weather and climate. DMS is generated largely by bacterial catabolism of dimethylsulfoniopropionate (DMSP), a secondary metabolite made by marine algae. We demonstrate that the bacterial gene dddD is required for this process and that its transcription is induced by the DMSP substrate. Cloned dddD from the marine bacterium Marinomonas and from two bacterial strains that associate with higher plants, the N(2)-fixing symbiont Rhizobium NGR234 and the root-colonizing Burkholderia cepacia AMMD, conferred to Escherichia coli the ability to make DMS from DMSP. The inferred enzymatic mechanism for DMS liberation involves an initial step in which DMSP is modified by addition of acyl coenzyme A, rather than the immediate release of DMS by a DMSP lyase, the previously suggested mechanism.

In this paper we combine the largest minimum distance algorithm and the traditional K-Means algorithm to propose an improved K-Means clustering algorithm. This improved algorithm can make up the shortcomings for the traditional K-Means algorithm to determine the initial focal point. The improved K-Means algorithm effectively solved two disadvantages of the traditional algorithm, the first one is greater dependence to choice the initial focal point, and another one is easy to be trapped in local minimum [1][2].

Montgomery algorithm will die N operation into shift operation, optimized Systolic array with fewer resources to achieve efficient Montgomery algorithm, and the application of power conversion technology to further improve the RSA encryption,decryption speed. In order to make full use of FPGA resources, this paper analyzes the impact of the Systolic array at different levels of granularity on the performance of the system, and gives the realization and S = key and encryption,decryption information are RSA encryption system of s hardware 1024 time results.

Intrusion Detection system (IDS) is a important element of Defense in Depth,which is able to capture all data in the LAN and analyse them for finding intrusional behavior. This paper presents conception of intrusion detection system.Snort that is a network based intrusion detection tool is analyzed,from the aspect of system structure and collectivity flow.Finally,snort base intrusion detection system is constructed and validated by our experiment.The result proves that the intrusional behavior isdetected effectively by using the system.