A convex model for nonnegative matrix factorization and dimensionality reduction on physical space

A collaborative convex framework for factoring a data matrix X into a nonnegative product AS , with a sparse coefficient matrix S, is proposed. We restrict the columns of the dictionary matrix A to coincide with certain columns of the data matrix X, thereby guaranteeing a physically meaningful dictionary and dimensionality reduction. We use l(1, ∞) regularization to select the dictionary from the data and show that this leads to an exact convex relaxation of l(0) in the case of distinct noise-free data. We also show how to relax the restriction-to- X constraint by initializing an alternating minimization approach with the solution of the convex model, obtaining a dictionary close to but not necessarily in X. We focus on applications of the proposed framework to hyperspectral endmember and abundance identification and also show an application to blind source separation of nuclear magnetic resonance data.     

Boolean restriction categories and taut monads

A Boolean category is a restriction category if and only if it has one exception and all morphisms are deterministic. In the category of sets, taut monads are precisely the Boolean ones. It follows that collection monad types in Haskell inherit an assertion calculus based on dynamic logic.     

清洁剂工业的全球协作

概述了全球范围内清洁剂工业的发展现状及目前清洁剂产品配方开发的限制因素，并对这些限制因素的变化趋势做了预测。介绍了美国多盟的一些清洁剂化学品检测标准，预测了未来清洁剂工业发展的方向，指出未来剂工业界全球协作的必要性。     

Durability of green polyurethane adhesive bonded aluminum alloy in dry and hydrothermal ageing conditions

Polyurethane (PU) adhesives were prepared from the reaction of polycaprolactone (PCL) polyols based on palm kernel oil based polyesteramide (PPKO) with an aromatic and cycloaliphatic diisocyanate. Four different formulations of PU adhesives were prepared by varying the NCO : OH ratio, in order to investigate the effects of NCO : OH ratios on adhesion strength. The adhesive strength of metal–metal bonding both in dry and hydrothermal ageing—was determined by single lap shear joint testing. The resistance to hydrolysis of the PU adhesives was determined by performing water absorption tests. The water absorption test samples suggested that the durability of the adhesives correlated to lower water absorption due to higher NCO content. The correlation between the crosslinking of the PU network and adhesive strength was also studied by performing swelling tests. The higher NCO content showed that, the higher crosslink density of PUs led to higher cohesion and adhesion strengths. PU1.7 showed optimal properties in terms of durability and resistance to hydrolysis, whereas PU2.0 revealed deterioration in durability and resistance to hydrolysis due to the presence of greater micro‐voids content in the PU2.0 matrix. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41151.     

国际化学法规对清洗产品的蕴含

演讲提纲 我将首先简单介绍美国肥皂与洗涤剂协会及我们在化学品管理中所扮演的角色.     

Comment on “Measurements of the temperature dependent diffusion coefficient of nanoparticles in the range of 295–600 K at atmospheric pressure” by V.Y. Rudyak,S.N. Dubtsov,A.M. Baklanov

In a recent paper in this journal, Rudyak, Dubtsov, and Baklanov (2009) presented results of measurements of the penetration of nanoparticles with diameters from 3.5 to 84 nm at temperatures from ～300 to 600 K through a set of wire screens, from which they inferred diffusion coefficients. They argued that the formulation typically used for C, the Cunningham correction that accounts for non-continuum effects on the diffusion of nanoparticles, is not valid for temperatures greater than ～300 K, and they proposed a modification of this formulation which depends on both temperature and particle size. It is shown here that this modification produces unphysical results in that it yields negative values of the momentum accommodation coefficient. A likely reason for their results is that they used a polydisperse size distribution, for which the main contribution to the measured penetration would be from particles at sizes far from those attributed to them.     

Simplified security notions of direct anonymous attestation and a concrete scheme from pairings

Direct Anonymous Attestation (DAA) is a cryptographic mechanism that enables remote authentication of a user while preserving privacy under the user’s control. The DAA scheme developed by Brickell, Camenisch, and Chen has been adopted by the Trust Computing Group for remote anonymous attestation of Trusted Platform Module, which is a small hardware device with limited storage space and communication capability. In this paper, we provide two contributions to DAA. We first introduce simplified security notions of DAA including the formal definitions of user controlled anonymity and traceability. We then propose a new DAA scheme from elliptic curve cryptography and bilinear maps. The lengths of private keys and signatures in our scheme are much shorter than the lengths in the original DAA scheme, with a similar level of security and computational complexity. Our scheme builds upon the Camenisch–Lysyanskaya signature scheme and is efficient and provably secure in the random oracle model under the LRSW (stands for Lysyanskaya, Rivest, Sahai and Wolf) assumption and the decisional Bilinear Diffie–Hellman assumption.     

Bionanocomposite hybrid polyurethane foam reinforced with empty fruit bunch and nanoclay

Bionanocomposite hybrid polyurethane (BHPU) foams that exploit the tribute of natural fibers and nanoclay in green PU foam can lead to the new imminent in engaging the nanoclay and natural fibers. PU filled empty fruit bunch (EFB), PU filled silane treated EFB (sEFB) and PU filled organo montmorillonite (oMMT) have been prepared as control, and the hybridization has carried out for ¼, ½ and ¾ ratios between EFB/oMMT and sEFB/oMMT. The hybridization of these natural fibers and oMMT permit to retain the strength without compromise the stiffness of BHPU. The hybridization also improves the barrier and thermal properties of these BHPU. Microscopic studies shows that the hybridization of these natural fibers and nanoclay provide initial evidence of the possibilities on the insertion of nanoclay into the natural fibers, thus open the opportunities to exploit this behavior to another hybrid system.     

The reduction of 2-chloro-benzoic acid

The reduction of 2-chloro-benzoic acid has been studied at the Hg, Pb, Sn, Zn and C electrodes.