Information preserving statistical obfuscation

The problem of limiting the disclosure of information gathered on a set of companies or individuals (the respondents) is considered, the aim being to provide useful information while preserving confidentiality of sensitive information. The paper proposes a method which explicitly preserves certain information contained in the data. The data are assumed to consist of two sets of information on each respondent: public data and specific survey data. It is assumed in this paper that both sets of data are liable to be released for a subset of respondents. However, the public data will be altered in some way to preserve confidentiality whereas the specific survey data is to be disclosed without alteration. The paper proposes a model based approach to this problem by utilizing the information contained in the sufficient statistics obtained from fitting a model to the public data by conditioning on the survey data. Deterministic and stochastic variants of the method are considered.     

阿兰·雷富礼：领导变革

6年前，宝洁公司深陷泥潭，业绩连年下滑，公司管理层在四个月内连续三次发布利润预警，公司最危险的时候，股价曾经在一日之内骤跌30％，市值大幅缩水。雷富礼临危受命，成为这家全球第一日化品牌的新任掌门人。     

Case study for evaluating campus sustainability: nitrogen balance for the University of Minnesota

American ecologists recently began to address the ecology of cities. Concurrently, higher education institutions have developed sustainability education programs and instituted sustainability policies and projects. This paper draws together these two disparate areas by examining the nitrogen (N) budget of the Twin Cities campus of the University of Minnesota. We addressed the question: what were the annual inputs, outputs and internal cycles of N on the University of Minnesota Twin Cities campus? We found that 508 Mg N yr-1 were brought into the campus and 494 Mg N yr-1 were emitted from the University of Minnesota campus. The largest N inputs were abiotic fixation (conversion of N₂ to NO_x by combustion) and food for humans and animals. The largest N output was NO_x, followed by wastewater. Our results expand the understanding of the ecology of institutions within an urban area and provide an opportunity for improving urban ecology education and environmental policy at educational institutions.