The Threat of Unsolicited Sessions in the 3GPP IP Multimedia Subsystem

Unsolicited emails distributed by marketers and fraudsters are a growing burden on Internet users. It is expected that with the introduction of low-cost next-generation networks, such as the IP multimedia subsystem, these unsolicited communications will migrate from email and move to voice, video, and instant messaging sessions. Unsolicited voice and video calls are highly disruptive, causing frustration to end users, and they are wasteful of network resources. These communications also may involve fraud, phishing, or the propagation of offensive material. This article highlights the scale of this inevitable problem and proposes mechanisms to enable users to filter their incoming multimedia sessions, such that only legitimate calls are received. This is achieved in a variety of ways including call-pattern analysis, statistical filtering, blacklists, whitelists, and challenge-response mechanisms.     

降烯烃催化剂RFG-FS3的工业应用试验

RFG-FS3催化剂是美国Grace Davison公司研制开发的用于降低催化裂化汽油烯烃含量的催化剂，该剂在抚顺石化分公司石油二厂1.5Mt/a催化裂化装置工业应用试验结果表明，降烯烃效果较好，在降低汽油烯烃含量的同时，汽油的辛烷值有所提高，液化气和柴油性质没有变化，与原使用的LV-23BC催化剂相比，在掺炼60%减压渣油，平衡催化剂活性保持较低时，该催化剂对重油转化能力稍差；增加新鲜催化剂补充率提高平衡催化剂活性后，当原料中掺炼40%常压渣油和40%减压渣油时，总液体收率和油浆产率基本不变。