647 research outputs found
D’Agents: Security in a Multiple-Language, Mobile-Agent System
Abstract. Mobile-agent systems must address three security issues: protecting an individual machine, protecting a group of machines, and protecting an agent. In this chapter, we discuss these three issues in the context of D’Agents, a mobile-agent system whose agents can be written in Tcl, Java and Scheme. (D’Agents was formerly known as Agent Tcl.) First we discuss mechanisms existing in D’Agents for protecting an individual machine: (1) cryptographic authentication of the agent’s owner, (2) resource managers that make policy decisions based on the owner’s identity, and (3) secure execution environments for each language that enforce the decisions of the resource managers. Then we discuss our planned market-based approach for protecting machine groups. Finally we consider several (partial) solutions for protecting an agent from a malicious machine.
In the Supreme Court of the United States Barbara Grutter, Petitioner, v. Lee Bollinger, et al., Respondents. On Writ of Certiorari to the United States Court of Appeals for the Sixth Circuit
Brief of the University of Michigan Asian Pacific American Law Students Association, the University of Michigan Black Law Students\u27 Alliance, the University of Michigan Latino Law Students Association, and the University of Michigan Native American Law Students Association as Amici Curiae in Support of Respondent
In the Supreme Court of the United States Barbara Grutter, Petitioner, v. Lee Bollinger, et al., Respondents. On Writ of Certiorari to the United States Court of Appeals for the Sixth Circuit
Brief of the University of Michigan Asian Pacific American Law Students Association, the University of Michigan Black Law Students\u27 Alliance, the University of Michigan Latino Law Students Association, and the University of Michigan Native American Law Students Association as Amici Curiae in Support of Respondent
Modification of glassy carbon electrodes by 4-chloromethylphenyl units and d-glucosaminic acid
The present work is dealing with the attachment of d-glucosaminic acid (D-GA) on glassy carbon electrode by two different methods. Firstly, the electrode was modified by chloromethylphenyl groups by reduction of 4-chloromethylphenyldiazonium cations followed by the nucleophilic substitution of the chlorine by the amine functionality of D-GA and secondly by the direct immobilization of the amine terminated molecule. The generality of the nucleophilic substitution reaction and the direct immobilization of an amine were also demonstrated with reactants bearing an electroactive ferrocene moiety; 4-nitrophenylferrocene (NFc) and 4-ferrocenylaniline (FcA). The surfaces modified with FcA and NFc were investigated by cyclic voltammetry, and the D-GA modified electrodes were characterized by X-ray photoelectron spectroscopy. A preliminary evaluation of the efficiency of these surface modifiers to prevent protein adsorption was realized by scanning electron microscopy
Determination of Bond Dissociation Enthalpies in Solution by Photoacoustic Calorimetry
NRC publication: Ye
Electroluminescence stabilization of nanocrystalline porous silicon diodes
NRC publication: Ye
An Electrochemical Study of Frustrated Lewis Pairs: A Metal-free Route to Hydrogen Oxidation
[Image: see text] Frustrated Lewis pairs have found many applications in the heterolytic activation of H(2) and subsequent hydrogenation of small molecules through delivery of the resulting proton and hydride equivalents. Herein, we describe how H(2) can be preactivated using classical frustrated Lewis pair chemistry and combined with in situ nonaqueous electrochemical oxidation of the resulting borohydride. Our approach allows hydrogen to be cleanly converted into two protons and two electrons in situ, and reduces the potential (the required energetic driving force) for nonaqueous H(2) oxidation by 610 mV (117.7 kJ mol(–1)). This significant energy reduction opens routes to the development of nonaqueous hydrogen energy technology
Mechanical tuning of the evaporation rate of liquid on crossed fibers
We investigate experimentally the drying of a small volume of perfectly
wetting liquid on two crossed fibers. We characterize the drying dynamics for
the three liquid morphologies that are encountered in this geometry: drop,
column and a mixed morphology, in which a drop and a column coexist. For each
morphology, we rationalize our findings with theoretical models that capture
the drying kinetics. We find that the evaporation rate depends significantly on
the liquid morphology and that the drying of liquid column is faster than the
evaporation of the drop and the mixed morphology for a given liquid volume.
Finally, we illustrate that shearing a network of fibers reduces the angle
between them, changes the morphology towards the column state, and so enhances
the drying rate of a volatile liquid deposited on it
Hole transfer equilibrium in rigidly linked bichromophoric molecules
Two bichromophoric molecules consisting of anthracene and diphenylpolyene moieties linked by two fused norbornyl bridges undergo photoionization upon ultraviolet (UV) pulsed laser irradiation. The simultaneous observation of the cation radicals of both anthracene and polyene groups points to a rapid (nanosecond or faster) intramolecular hole transfer equilibrium between the two chromophores. The existence of an equilibrium is supported by the results of one- and two-laser transient absorption and electrochemical experiments. Equilibrium constants (293 K) were determined by both transient absorption and cyclic voltammetry measurements and were independent of the method used within experimental error. For A-sp-VB, which contains anthracene and vinyldiphenylbutadiene chromophores, Keq = 4.0 ? 2 (transient absorption) and 3.2 ? 2 (electrochemical), favoring the anthracene cation radical. For A-sp-VS, containing anthracene and vinylstilbene groups, Keq = 70 ? 30 (transient absorption) and 105 ? 50 (electrochemical), favoring the anthracene cation radical.Peer reviewed: YesNRC publication: Ye
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