Abstract: The present invention provides methods, devices, and systems for detecting and filtering SPam over Internet Telephony (SPIT). The invention includes a two level filter. The first level may include a robust audio hash used to filter audio messages based on their audio content and the second level may include a near-duplicate pattern matching algorithm having a number of content filters and an evaluator to aggregate the results from the multiple content filters. By supporting multiple aggregation methods, a more flexible SPIT detection scheme is provided.

Abstract: A method for preparing hydroxylamine is provided that includes the steps of (i) pretreating an acidic buffer solution; and (ii) reducing nitrate ions in the acidic buffer solution with hydrogen to give hydroxylamine in the presence of catalysts, wherein the pretreatment is performed by adding a precipitant represented by formula (I) to the acidic buffer solution, [(A)aM(CN)6.xH2O]??(I) allowing the metal impurities in the acidic buffer solution to react with the precipitant to form metal complex, and then to remove the metal complex. The metal complex is formed and separated by pretreating the acidic buffer solution with a specific precipitant without adjusting pH and changing the composition of the acidic buffer solution prior to hydroxylamine synthesis, thus enhancing the selectivity of the hydroxylamine production.

Abstract: A method for preparing hydroxylamine is provided that includes the steps of (i) pretreating an acidic buffer solution; and (ii) reducing nitrate ions in the acidic buffer solution with hydrogen to give hydroxylamine in the presence of catalysts, wherein the pretreatment is performed by adding a precipitant represented by formula (I) to the acidic buffer solution, [(A)aM(CN)6.xH2O]??(I) allowing the metal impurities in the acidic buffer solution to react with the precipitant to form metal complex, and then to remove the metal complex. The metal complex is formed and separated by pretreating the acidic buffer solution with a specific precipitant without adjusting pH and changing the composition of the acidic buffer solution prior to hydroxylamine synthesis, thus enhancing the selectivity of the hydroxylamine production.