Design of Distributed Authentication Mechanism for Equipment Support Information Network

Considering the secure authentication problem for equipment support information network,a clustering method based on the business information flow is proposed. Based on the proposed method,a cluster-based distributed authentication mechanism and an optimal design method for distributed certificate authority( CA)are designed. Compared with some conventional clustering methods for network,the proposed clustering method considers the business information flow of the network and the task of the network nodes,which can decrease the communication spending between the clusters and improve the network efficiency effectively. The identity authentication protocols between the nodes in the same cluster and in different clusters are designed. From the perspective of the security of network and the availability of distributed authentication service,the definition of the secure service success rate of distributed CA is given and it is taken as the aim of the optimal design for distributed CA. The efficiency of providing the distributed certificate service successfully by the distributed CA is taken as the constraint condition of the optimal design for distributed CA. The determination method for the optimal value of the threshold is investigated. The proposed method can provide references for the optimal design for distributed CA.

Distribution of Exchangeable Calcium，Magnesium and Potassium as Affected by Fertilizer Application to Red Soil

A leaching experiment was carried out with repacked soil columns in laboratory to stndy the leachingprocess of a red soil derived from sandstone as affected by warions fertilization practices. The treatments wereCK (as a control), CaCO_3, CaSO_4, MgCO_3, Ca(H_2PO_4)_2, Urea, KCl, Mnltiple (a mixture of the above-mentioned fertilizers), and KNO_3. The fertilizers were added to the bare surface of the soil columns, andthen the columns were leached with 120 mL deionized water daily through peristaltic pumps over a periodof 92 days. At the end of leaching process, soils were sampled from different depths of the soil profiles, i.e.,0-5 cm, 5-10 cm, 10-20 cm, 20-40 cm, and 40-60 cm. The results showed when applying Ca, Mg, andK to the bare surface of the soil columns, exchangeable Ca￣(2+), Mg￣(2+), and K￣+ in the upper layer of thesoil profile increased correspondingly, with an extent depending mainly on the application rates of Ca, Mg,and K and showing a downward trend. CaCO_3, CaSO_4, MgCO_3, and Ca(H_2PO_4)_2 treatments had scarcelyany effect on movement of exchangeable K￣+, while CaCO_3, and CaSO_4 treatments significantly promotedthe downward movement of exchangeable Mg￣(2+) although these two treatments had no obvious effect onleaching losses of Mg. The fact that under Urea treatment, exchangeable Ca￣(2+) and Mg￣(2+) were higheras compared to CK treatment showed urea could prevent leaching of exchangeable Ca￣(2+) and Mg￣(2+). Theobvious downward movement of exchangeable Ca￣(2+) and Mg￣(2+) was noticed in KCl treatment. In Multipletreatment, the downward movement of exchangeable Ca￣(2+) and Mg￣(2+) was evident, while that of K￣+ was lessevident. Application of KNO_3 strongly promoted the downward movement of exchangeable Ca￣(2+) and Mg￣(2+)in the soil profile.