Data envelopment analysis (DEA) has gained great popularity in environmental performance measurement because it can provide a synthetic standardized environmental performance index when pollutants are suitably incorporated into the traditional DEA framework. Past studies about the application of DEA to environmental performance measurement often follow the concept of radial efficiency measures....

Advances in data acquisition have allowed large data collections of millions of time varying records in the form of data streams. The challenge is to effectively process the stream data with limited resources while maintaining sufficient historical information to define the changes and patterns over time. This paper describes an evidence-based approach that uses representative points to increme...

Data releases to the public should ensure the privacy of individuals involved in the data. Several privacy mechanisms have been proposed in the literature. One such technique is that of data anonymization. For example, synthetic data sets are generated and released. In this paper we analyze the privacy aspects of synthetic data sets. In particular, we introduce a natural notion of privacy and e...

This paper reports an experiment aimed at generating synthetic test data for fraud detection in an IP based videoon-demand service. The data generation verifies a methodology previously developed by the present authors [7] that ensures that important statistical properties of the authentic data are preserved by using authentic normal data and fraud as a seed for generating synthetic data. This ...

In this paper, we propose a new algorithm, called ClaSP for mining frequent closed sequential patterns in temporal transaction data. Our algorithm uses several efficient search space pruning methods together with a vertical database layout. Experiments on both synthetic and real datasets show that ClaSP outperforms currently well known state of the art methods, such as CloSpan.

Suppose Q is the covariance matrix for the returns of n assets. Then Q is symmetric (qij = qji for all indices i, j) and positive-semidefinite (v Qv ≥ 0 for any vector v ∈ R – this is denoted Q 0). We want to “explain” Q using a small number of synthetic factors, i.e. factors that are determined from the data itself, as opposed to using economic factors. If r is the number of factors (typically...

A single parameter value that represents the difference between the original and the digitized characters is determined from a binary scan of a test chart. It represents the combined effect of the point spread function diameter and the binary intensity threshold and is used to generate synthetic characters that are similar to characters scanned under the same conditions as the test chart.