Caching and Auditing in the RPPM Model

Crampton and Sellwood recently introduced a variant of relationship-based access control based on the concepts of relationships, paths and principal matching, to which we will refer as the RPPM model. In this paper, we show that the RPPM model can be extended to provide support for caching of authorization decisions and enforcement of separation of duty policies. We show that these extensions are natural and powerful. Indeed, caching provides far greater advantages in RPPM than it does in most other access control models and we are able to support a wide range of separation of duty policies.Comment: Accepted for publication at STM 2014 (without proofs, which are included in this longer version

Charmed Baryon Weak Decays with SU(3) Flavor Symmetry

We study the semileptonic and non-leptonic charmed baryon decays with $SU(3)$ flavor symmetry, where the charmed baryons can be ${\bf B}_{c}=(\Xi_c^0,\Xi_c^+,\Lambda_c^+)$, ${\bf B}'_{c}=(\Sigma_c^{(++,+,0)},\Xi_{c}^{\prime(+,0)},\Omega_c^0)$, ${\bf B}_{cc}=(\Xi_{cc}^{++},\Xi_{cc}^+,\Omega_{cc}^+)$, or ${\bf B}_{ccc}=\Omega^{++}_{ccc}$. With ${\bf B}_n^{(\prime)}$ denoted as the baryon octet (decuplet), we find that the ${\bf B}_{c}\to {\bf B}'_n\ell^+\nu_\ell$ decays are forbidden, while the $\Omega_c^0\to \Omega^-\ell^+\nu_\ell$, $\Omega_{cc}^+\to\Omega_c^0\ell^+\nu_\ell$, and $\Omega_{ccc}^{++}\to \Omega_{cc}^+\ell^+\nu_\ell$ decays are the only existing Cabibbo-allowed modes for ${\bf B}'_{c}\to {\bf B}'_n\ell^+\nu_\ell$, ${\bf B}_{cc}\to {\bf B}'_c\ell^+\nu_\ell$, and ${\bf B}_{ccc}\to {\bf B}_{cc}^{(\prime)}\ell^+\nu_\ell$, respectively. We predict the rarely studied ${\bf B}_{c}\to {\bf B}_n^{(\prime)}M$ decays, such as ${\cal B}(\Xi_c^0\to\Lambda^0\bar K^0,\,\Xi_c^+\to\Xi^0\pi^+)=(8.3\pm 0.9,8.0\pm 4.1)\times 10^{-3}$ and ${\cal B}(\Lambda_c^+\to \Delta^{++}\pi^-,\,\Xi_c^0\to\Omega^- K^+)=(5.5\pm 1.3,4.8\pm 0.5)\times 10^{-3}$. For the observation, the doubly and triply charmed baryon decays of $\Omega_{cc}^{+}\to \Xi_c^+\bar K^0$, $\Xi_{cc}^{++}\to (\Xi_c^+\pi^+$, $\Sigma_c^{++}\bar K^0)$, and $\Omega_{ccc}^{++}\to (\Xi_{cc}^{++}\bar K^0,\Omega_{cc}^+\pi^+,\Xi_c^+ D^+)$ are the favored Cabibbo-allowed decays, which are accessible to the BESIII and LHCb experiments.Comment: 29 pages, no figure, a typo in the table correcte

Visualization of Gas–Oil–Water Flow in Horizontal Pipeline Using Dual-Modality Electrical Tomographic Systems

Employing dual-modality tomography inherently involves data from multiple dimensions, and thus a coherent approach is required to fully exploit the information from various dimensions. This paper describes a novel approach for dual-modality electrical resistance and capacitance tomography (ERT-ECT) to visualize gas-oil-water flow in horizontal pipeline. Compared with the conventional methods with dual-modality tomographic systems, the approach based on thresholding takes the account of multi-dimensional data, which therefore is capable of providing insights into investigated flow in both spatial and temporal terms. The experimental results demonstrate the feasibility of the approach, by which six common flow regimes in horizontal pipeline flow are visualized based on the multi-dimensional data with ERT-ECT systems, including (wavy) stratified flow, plug flow, slug flow, annular flow, and bubbly flow. Although the present approach is proposed for data acquired with an ERT-ECT system, it is potentially adaptable to other dual-modality tomographic systems that use concentration tomograms as inputs

Who Can “Seize the Day?”: Analyzing Who Is an “Employee” for Purposes of Unionization and Collective Bargaining Through the Lens of the “Newsie” Strike of 1899

In the summer of 1899, the Newsboys of New York banded together, formed a union, and began to “strike” against two of the city’s largest newspapers in response to a price increase. After a two-week struggle, the newspaper companies agreed to compromise by buying back any unsold papers at the end of the day from the Newsboys. They did not, however, agree to the Newsboys’ classification of the effort as a “strike.” The newspapers saw this as a boycott of non-employees, or independent contractors. After the turn of the century, Congress began to pass laws protecting employees, and in 1935 they passed the National Labor Relations Act (NLRA), which protected employees’ rights to unionize, collectively bargain, and strike. The Newsboys, eager to solidify their rights, argued to the Supreme Court in 1944, in NLRB. v. Hearst Publications, Inc., that they were in fact employees. Although the Court agreed, Congress did not, and in response passed the “Taft-Hartley” amendments to the NLRA. These amendments excluded independent contractors from the definition of employee, introducing a major issue into the labor realm—how do you differentiate between an independent contractor and an employee for the purposes of unionization and collective bargaining? This Note examines the distinction between employees and independent contractors through the case example of the Newsboys and ponders if the distinction is necessary or if it merely denies workers’ rights

Demonstration of dual gain mechanism in an InGaAs/InAlAs superlattice photodiode

A high‐gain photodiode in which the internal gain can result from either potential barrier lowering or mass filtering action, depending on device geometry and bias conditions, is proposed and demonstrated. The photodiode structure is similar to a modulated barrier diode and uses In0.53Ga0.47As and InGaAs/InAlAs superlattice absorption regions. The superlattice helps to reduce the dark current and aids in mass filtering. The devices reported here were made with multilayered InP‐based materials grown by molecular beam epitaxy and exhibit responsivity as high as 1000 A/W.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69816/2/APPLAB-50-17-1176-1.pd

Probing tiny motions of nanomechanical resonators: classical or quantum mechanical?

We propose a spectroscopic approach to probe tiny vibrations of a nanomechanical resonator (NAMR), which may reveal classical or quantum behavior depending on the decoherence-inducing environment. Our proposal is based on the detection of the voltage-fluctuation spectrum in a superconducting transmission line resonator (TLR), which is {\it indirectly} coupled to the NAMR via a controllable Josephson qubit acting as a quantum transducer. The classical (quantum mechanical) vibrations of the NAMR induce symmetric (asymmetric) Stark shifts of the qubit levels, which can be measured by the voltage fluctuations in the TLR. Thus, the motion of the NAMR, including if it is quantum mechanical or not, could be probed by detecting the voltage-fluctuation spectrum of the TLR.Comment: 4 pages, 3 figures. to appear in Physical Review Letter