Unconditionally Secure Oblivious Polynomial Evaluation: A Survey and New Results

Oblivious polynomial evaluation (OPE) is a two-party protocol that allows a receiver, R to learn an evaluation f(α), of a sender, S's polynomial f(x), whilst keeping both α and f(x) private. This protocol has attracted a lot of attention recently, as it has wide ranging applications in the field of cryptography. In this article we review some of these applications and, additionally, take an in-depth look at the special case of information theoretic OPE. Specifically, we provide a current and critical review of the existing information theoretic OPE protocols in the literature. We divide these protocols into two distinct cases (three-party and distributed OPE) allowing for the easy distinction and classification of future information theoretic OPE protocols. In addition to this work, we also develop several modifications and extensions to existing schemes, resulting in increased security, flexibility and efficiency. Lastly, we also identify a security flaw in a previously published OPE scheme.     

Formal verification of OIL component specifications using mCRL2

International Journal on Software Tools for Technology Transfer - To aid in making software bug-free, several high-tech companies are moving from coding to modelling. In some cases model checking...     

柔和之美

为了保持房间高度的最大化,行政酒廊的天花板上装饰的巨大叶片吊顶和屋顶之间的距离非常接近。在这里使用的照明装置是安装在吊顶之上的。这种照明装置经过特别的设计,避免了在吊顶之上出现的荧光灯管的条状光斑。整个设计感觉柔和,而又有效的避免了眩光的产生。我们在大堂的照     

Mapping an urban area prone to slope instability: Greater Lyons

In response to the needs of the local authorities, the systematic mapping of zones prone to slope instability was undertaken for the urban area of Lyons, the second largest city of France with a population of 1.2 million. This involved working within operational constraints, including the extent of the study sector (some 300 km² of the 500 km² covered by the urban area), an accuracy of 1:5,000 scale throughout, difficulties of ground observation in an urban environment and a limited budget. An original methodology was developed and implemented to deal with these constraints. This combined automatic mapping methods using GIS (cross-checking slope and geological criteria) with naturalistic assessment methods (visual analysis). The results obtained met the expectations of the local authorities. After checking, the maps produced were appended to the regulatory urban planning documents under development. Electronic Publication     

On the idea of ex ante and ex post normalization of biproportional methods

Biproportional methods project a matrix A to give it the column and row sums of another matrix; the result is R A S, where R and S are diagonal matrices. As R and S are not identified, one must normalize them, even after computing, that is, ex post. This article starts from the idea developed in de Mesnard (2002) – any normalization amounts to put constraints on Lagrange multipliers, even when it is based on an economic reasoning, – to show that it is impossible to analytically derive the normalized solution at optimum. Convergence must be proved when normalization is applied at each step on the path to equilibrium. To summarize, normalization is impossible ex ante, what removes the possibility of having a certain control on it. It is also indicated that negativity is not a problem.Received: October 2002/Accepted: June 2003     

A new contribution to the finite line-source model for geothermal boreholes

Heat transfer around vertical ground heat exchangers is a common problem for the design and simulation of ground-coupled heat pump (GCHP) systems. Most models are based on step response of the heat transfer rate, and the superposition principle allows the final solution to be in the form of the convolution of these contributions. The step response is thus a very important tool. Some authors propose numerical tabulated values while others propose analytical solutions for purely radial problem as well as axisymmetric problems. In this paper we propose a new analytical model that yields results very similar to the tabulated numerical ones proposed in the literature. Analytical modeling offers better flexibility for a parameterized design.     

Relationships among total recoverable and reactive metals and metalloid in St. Lawrence River sediment: bioaccumulation by chironomids and implications for ecological risk assessment

The availability and bioaccumulation of metals and metalloids, and the geochemical interactions among them, are essential to developing an ecological risk assessment (ERA) framework and determining threshold concentrations for these elements. The purpose of this study was to explore the relationships among total recoverable and reactive metals and metalloid in sediment and their bioaccumulation by chironomids. In the fall of 2004 and 2005, 58 stations located in the three fluvial lakes of the St. Lawrence River and its largest harbour area in Montreal, Canada, were sampled. Nine total recoverable and reactive metals (Al, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) and one metalloid (As) were measured in whole sediment using two extraction methods: HCl/HNO(3) and HCl 1N, respectively. The bioaccumulation of six metals (Cd, Cr, Cu, Ni, Pb and Zn) and As by chironomids was evaluated in a subset of 22 stations. Strong collinearities were observed between some total recoverable or reactive metal concentrations in sediment; two principal clusters, including collinear metals, were obtained. The first one included metals of mainly geological origin (Al, Cr, Fe, Mn, Ni), while the second one included As, Cd, Cu, Pb and Zn, which likely derive mainly from point sources of anthropogenic contamination. Each element also showed strong collinearity between their total recoverable and reactive forms (0.65< or =r < or =0.97). We can conclude that both chemical forms are equivalent for use in statistical models needed to explain biological responses and also in screening risk assessment. However, these relationships are not always proportional. Lower availability percentages were observed for Cd, Cu and Zn in the highly mixed-contaminated area of the Montreal Harbour, even though concentrations in sediment were higher. We observed a significant correlation (0.50< or =r < or =0.56) between concentrations in chironomids and concentrations of both total recoverable and reactive Cr and Pb in sediment. Arsenic was an exception, with accumulation by chironomids being highly related to reactive sediment concentrations. Finally, we observed variable influences of explanatory factors (e.g. sediment grain size, Al, Fe, Mn, S, TOC), depending on which metal or metalloid was being predicted in chironomids. In this context, it is difficult to choose a universal predictive method to explain the bioaccumulation of specific metals, and more research is still needed into normalization procedures that consider a combination of explanatory factors.     

King oil: a speculative opinion

This speculative opinion is based on an apparent dream caused by Donald Trump’s decision to withdraw the U.S. from the Paris Agreement. The account includes a comparison between arguments against the abolition of slavery and those against ending a fossil-fuel based economy in favor of sustainability through a green approach. Recent social disturbance in France shows that a carbon tax has not been persuasively advocated. But it should be clear that unchanged laissez-faire economics will produce disaster in light of the facts about global heating and climate change. This account is based on historical and contemporary quotations from American political figures from both the XIX and XXI centuries. The parallels raise fundamental issues of human rights.     

Displacement field analysis for cracking processes in bonded-particle model

Bonded-particle model (BPM) is widely used to model the cracking processes in rock/rock-like materials. However, the discrete particles in the BPM cannot produce a continuous displacement field, which is comparable with those in physical experiments and numerical method such as the finite element method. Displacement trend lines are introduced to analyze the displacement field type of the BPM in the present study. Three displacement field types (DF_I, DF_II and DF_III) are defined and used in the analysis of the cracking processes. The study shows that the type of displacement field may evolve during the cracking processes. Researchers are advised to examine the displacement field before and right after a particular crack has formed. An examination of the associated type of displacement field can help reveal the nature of the crack.     

双年展:一种建筑批评的开始

2002上海双年展以“都市营造”为主题第一次使艺术家与建筑师会聚堂。作品的呈现是对中国当代建筑与城市的多维审思,也是一种建筑批评的开始。