Spam over Internet Telephony (SPIT) is a new form of spam delivered using the phone network. With the low cost of Internet telephony, SPIT has become an attractive alternative for spammers to carry out unsolicited marketing and phishing. SPIT is more intrusive than email spam as it demands immediate recipient attention. In this paper, we study characteristics of communications in a phone network with the objective of identifying "SPITters". We collect and analyze the data from one of the largest phone providers in North America. First, we propose a new technique, Loose Tie Detection (LTD), to identify outliers based on social ties. Second, we introduce Enhanced Progressive Multi Grey-Leveling (EPMG), which identifies outliers based on call density and reciprocity. Finally, we propose SymRank, an adaptation of the PageRank algorithm that computes the reputation of subscribers based on both incoming and outgoing calls. We evaluate the three techniques and find that they compute an overlapping set of outliers. Our experiments reveal that LTD and SymRank -although seemingly independent approachesclosely match with regard to outliers, thus showing that our techniques are effective in identifying SPITters.

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Safety instrumented systems are now well recognized and utilized by various operational companies in oil and gas majorly in integrated plants such as refineries, upgraders and petrochemical plants based on the both reliability and availability of these systems to prevent and mitigate any risk associated with any high consequence initiating event. The SIS requirements are well developed and globally accepted within IEC61511 and ISA84.01 standards in which the safety lifecycle requirements have to be met. The initial implementation of SIS in each plant has always been a challenging program because it needs tremendous effort to develop processes and procedures to meet any single clause of the lifecycle. At the same time, following the engineering best practices is another key factor of success for this implementation. However, in pipeline operations industry, there are additional aspects regarding risk management, design, operations and maintenance of the SIS, which have to be considered in addition to all code requirements and considerations on the integrated plants such as refineries, as mentioned above. These special considerations should not be underestimated and have to be dealt with as special requirements for the industry. These aspects raise sets of technical challenges for any implementation initiative and other planning or execution challenges which are directly related to the safety lifecycle.