Abstract: The present invention provides a system for measuring concentrations of analytes. The system comprises a sampler (17) for taking at least one sample from each of one or more surfaces. The system also comprises an analyser (19) for analysing the at least one sample to determine the concentrations of the analytes on the sampled one or more surfaces. The system further comprises a management platform (43) for receiving the measured concentrations from the analyser and communicating the concentrations of the analytes on the one or more surface, wherein the system provides the results within a suitable time.

Abstract: Several techniques for sorting item are described, generally referred to as (1) common prefix skipping quicksort; (2) key substring caching; and (3) adaptive quicksort. With common prefix skipping quicksort, common prefix bytes among all key values for a partition are computed while performing a quicksort partitioning operation, and the known common bytes are skipped when comparing two key values in a recursive partitioning operation. With key substring caching, each item is represented in a cached array comprising a particular number of bytes for respective portions of key values (“key substring”), where the key substring cache is updated contain bytes beyond the known number of common prefix bytes. An adaptive quicksort routine is a hybrid of a quicksort function and most significant digit radix sort function, where the functions are mutually recursive.

Abstract: Key conditioning involves the construction of a byte orderable array from values for a possibly multi-field key concatenated key, for comparison by a sort routine. Byte-orderable sort keys are conditioned prior to execution of a sort routine, to facilitate an accurate and/or efficient sort procedure. For example, key conditioning may be applied to values in one or more columns of a database table, where the column(s) are used as keys for sorting rows of the table. Six factors are considered in encoding the byte array, such as whether nulls compare high or low; whether a field is fixed width or variable width; whether a field is guaranteed to be not null; whether a field is ordered ascending or descending; whether a field is the last field of a multi-field sort key or the only field of a sort key; and whether a field is likely to contain a significant number of zero values.

Abstract: Techniques are provided for (1) extending SQL to support direct invocation of frequent itemset operations, (2) improving the performance of frequent itemset operations by clustering itemset combinations to more efficiently use previously produced results, and (3) making on-the-fly selection of the occurrence counting technique to use during each phase of a multiple phase frequent itemset operation. When directly invoked in an SQL statement, a frequent itemset operation may receive input from results of operations specified in the SQL statement, and provide its results directly to other operations specified in the SQL statement. By clustering itemset combinations, resources may be used more efficiently by retaining intermediate information as long as it is useful, and then discarding it to free up volatile memory.