MVG Mechanism: Differential Privacy under Matrix-Valued Query

Differential privacy mechanism design has traditionally been tailored for a scalar-valued query function. Although many mechanisms such as the Laplace and Gaussian mechanisms can be extended to a matrix-valued query function by adding i.i.d. noise to each element of the matrix, this method is often suboptimal as it forfeits an opportunity to exploit the structural characteristics typically associated with matrix analysis. To address this challenge, we propose a novel differential privacy mechanism called the Matrix-Variate Gaussian (MVG) mechanism, which adds a matrix-valued noise drawn from a matrix-variate Gaussian distribution, and we rigorously prove that the MVG mechanism preserves $(\epsilon,\delta)$-differential privacy. Furthermore, we introduce the concept of directional noise made possible by the design of the MVG mechanism. Directional noise allows the impact of the noise on the utility of the matrix-valued query function to be moderated. Finally, we experimentally demonstrate the performance of our mechanism using three matrix-valued queries on three privacy-sensitive datasets. We find that the MVG mechanism notably outperforms four previous state-of-the-art approaches, and provides comparable utility to the non-private baseline.Comment: Appeared in CCS'1

Green process innovation: Where we are and where we are going

Environmental pollution has worsened in the past few decades, and increasing pressure is being put on firms by different regulatory bodies, customer groups, NGOs and other media outlets to adopt green process innovations (GPcIs), which include clean technologies and end-of-pipe solutions. Although considerable studies have been published on GPcI, the literature is disjointed, and as such, a comprehensive understanding of the issues, challenges and gaps is lacking. A systematic literature review (SLR) involving 80 relevant studies was conducted to extract seven themes: strategic response, organisational learning, institutional pressures, structural issues, outcomes, barriers and methodological choices. The review thus highlights the various gaps in the GPcI literature and illuminates the pathways for future research by proposing a series of potential research questions. This study is of vital importance to business strategy as it provides a comprehensive framework to help firms understand the various contours of GPcI. Likewise, policymakers can use the findings of this study to fill in the loopholes in the existing regulations that firms are exploiting to circumvent taxes and other penalties by locating their operations to emerging economies with less stringent environmental regulations.publishedVersio

Derivative UV/Vis spectroelectrochemistry in a thin-layer regime: deconvolution and simultaneous quantification of ascorbic acid, dopamine and uric acid

In this work, UV/Vis spectroelectrochemistry (SEC), in a thin-layer regime and parallel configuration, is selected to solve a complex mixture that contains dopamine (DA), ascorbic acid (AA) and uric acid (UA). These molecules, like many other biological compounds, are assuming a highly important place in analytical and biomedical fields due to the fundamental role that they play in human metabolism. In addition, low or high levels of these compounds are associated with diseases such as Parkinson’s disease. For this reason, the quantification of these biomolecules is becoming increasingly critical. However, some drawbacks must be overcome, because the three molecules coexist in the human body, and the species are subject to mutual interference. In fact, they are all oxidized at similar potentials, and their UV/Vis absorption bands overlap, greatly complicating their quantification. For this reason, derivative SEC together with suitable chemometric tools such as PARAFAC are proposed to solve this complex matrix. This technique allows us to separate the contribution of each of these molecules present in a sample and to quantify all of them, achieving high resolution and reproducibility. Besides, detection limits at the micromolar level are achieved for DA, AA and UA in mixture solutions. This work thus demonstrates the great potential for derivative potentiodynamic SEC combined with the appropriate chemometric tools in solving complex mixtures, a field where SEC is still taking the first steps.Ministerio de Economía y Competitividad (Grants CTQ2017-83935-RAEI/ FEDER, UE), Junta de Castilla y León (Grant BU297P18) and Ministerio de Ciencia, Innovación y Universidades (RED2018-102412- T). F.O. is grateful for the contract funded by Junta de Castilla y León, the European Social Fund and the Youth Employment Initiative. J.G.R. thanks theMinisterio de Economía y Competitividad for his postdoctoral contract (CTQ2017-83935-R AEI/FEDER, UE)

Some quantum chemical study on the structural properties of three unsymmetrical Schiff base ligands

In this studythree Schiff base ligands derived of 2-hydroxybenzaldehyde: H2L1, H2L2 and H2L3 have been subjected to theoretical studies by using density functional theory (DFT) calculations. The electronic properties such as highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO) energy, HOMO-LUMO gap energy, RHF energy, some of important bond lengths and angles, dipole moment and molecular densities have been investigated. Also the calculated IR spectra of these ligands are in good consistency with the experimental results. DOI: http://dx.doi.org/10.4314/bcse.v28i2.1