University of Waterloo

About: University of Waterloo is a education organization based out in Waterloo, Ontario, Canada. It is known for research contribution in the topics: Population & Context (language use). The organization has 36093 authors who have published 93906 publications receiving 2948139 citations. The organization is also known as: UW & uwaterloo.

k-automorphism: a general framework for privacy preserving network publication

Abstract: The growing popularity of social networks has generated interesting data management and data mining problems. An important concern in the release of these data for study is their privacy, since social networks usually contain personal information. Simply removing all identifiable personal information (such as names and social security number) before releasing the data is insufficient. It is easy for an attacker to identify the target by performing different structural queries. In this paper we propose k-automorphism to protect against multiple structural attacks and develop an algorithm (called KM) that ensures k-automorphism. We also discuss an extension of KM to handle "dynamic" releases of the data. Extensive experiments show that the algorithm performs well in terms of protection it provides.

A Lightweight Message Authentication Scheme for Smart Grid Communications

Abstract: Smart grid (SG) communication has recently received significant attentions to facilitate intelligent and distributed electric power transmission systems. However, communication trust and security issues still present practical concerns to the deployment of SG. In this paper, to cope with these challenging concerns, we propose a lightweight message authentication scheme features as a basic yet crucial component for secure SG communication framework. Specifically, in the proposed scheme, the smart meters which are distributed at different hierarchical networks of the SG can first achieve mutual authentication and establish the shared session key with Diffie-Hellman exchange protocol. Then, with the shared session key between smart meters and hash-based authentication code technique, the subsequent messages can be authenticated in a lightweight way. Detailed security analysis shows that the proposed scheme can satisfy the desirable security requirements of SG communications. In addition, extensive simulations have also been conducted to demonstrate the effectiveness of the proposed scheme in terms of low latency and few signal message exchanges.

A Systematic Review of Readability and Comprehension Instruments Used for Print and Web-Based Cancer Information

Abstract: Adequate functional literacy skills positively influence individuals' ability to take control of their health. Print and Web-based cancer information is often written at difficult reading levels. This systematic review evaluates readability instruments (FRE, F-K, Fog, SMOG, Fry) used to assess print and Web-based cancer information and word recognition and comprehension tests (Cloze, REALM, TOFHLA, WRAT) that measure people's health literacy. Articles on readability and comprehension instruments explicitly used for cancer information were assembled by searching MEDLINE and Psyc INFO from 1993 to 2003. In all, 23 studies were included; 16 on readability, 6 on comprehension, and 1 on readability and comprehension. Of the readability investigations, 14 focused on print materials, and 2 assessed Internet information. Comprehension and word recognition measures were not applied to Web-based information. None of the formulas were designed to determine the effects of visuals or design factors that could influence readability and comprehension of cancer education information.

Scattering equations and matrices: from Einstein to Yang-Mills, DBI and NLSM

Abstract: The tree-level S-matrix of Einstein’s theory is known to have a representation as an integral over the moduli space of punctured spheres localized to the solutions of the scattering equations In this paper we introduce three operations that can be applied on the integrand in order to produce other theories Starting in d + M dimensions we use dimensional reduction to construct Einstein-Maxwell with gauge group U(1) M The second operation turns gravitons into gluons and we call it “squeezing” This gives rise to a formula for all multi-trace mixed amplitudes in Einstein-Yang-Mills Dimensionally reducing Yang-Mills we find the S-matrix of a special Yang-Mills-Scalar (YMS) theory, and by the squeezing operation we find that of a YMS theory with an additional cubic scalar vertex A corollary of the YMS formula gives one for a single massless scalar with a ϕ4 interaction Starting again from Einstein’s theory but in d + d dimensions we introduce a “generalized dimensional reduction” that produces the Born-Infeld theory or a special Galileon theory in d dimensions depending on how it is applied An extension of Born-Infeld formula leads to one for the Dirac-Born-Infeld (DBI) theory By applying the same operation to Yang-Mills we obtain the U(N ) non-linear sigma model (NLSM) Finally, we show how the Kawai-Lewellen-Tye relations naturally follow from our formulation and provide additional connections among these theories One such relation constructs DBI from YMS and NLSM

Holographic phase transitions at finite baryon density

Abstract: We use holographic techniques to study SU(Nc) super Yang-Mills theory coupled to Nf << Nc flavours of fundamental matter at finite temperature and baryon density. We focus on four dimensions, for which the dual description consists of Nf D7-branes in the background of Nc black D3-branes, but our results apply in other dimensions as well. A non-zero chemical potential μb or baryon number density nb is introduced via a nonvanishing worldvolume gauge field on the D7-branes. Ref. [1] identified a first order phase transition at zero density associated with `melting' of the mesons. This extends to a line of phase transitions for small nb, which terminates at a critical point at finite nb. Investigation of the D7-branes' thermodynamics reveals that (∂μb/∂nb)T<0 in a small region of the phase diagram, indicating an instability. We comment on a possible new phase which may appear in this region.