University of California

About: University of California is a education organization based out in Oakland, California, United States. It is known for research contribution in the topics: Population & Layer (electronics). The organization has 55175 authors who have published 52933 publications receiving 1491169 citations. The organization is also known as: UC & University of California System.

Deconvolution and Estimation of Transfer Function Phase and Coefficients for NonGaussian Linear Processes.

Abstract: NonGaussian linear processes are considered. It is shown that the phase of the transfer function can be estimated under broad conditions. This is not true of Gaussian linear processes and in this sense Gaussian linear processes are atypical. The asymptotic behavior of a phase estimate is determined. The phase estimates make use of bispectral estimates. These ideas are applied to a problem of deconvolution which is effective even when the transfer function is not minimum phase. A number of computational illustrations are given.

GQ and Schnorr Identification Schemes: Proofs of Security against Impersonation under Active and Concurrent Attacks

Abstract: The Guillou-Quisquater (GQ) and Schnorr identification schemes are amongst the most efficient and best-known Fiat-Shamir follow-ons, but the question of whether they can be proven secure against impersonation under active attack has remained open. This paper provides such a proof for GQ based on the assumed security of RSA under one more inversion, an extension of the usual one-wayness assumption that was introduced in [5]. It also provides such a proof for the Schnorr scheme based on a corresponding discrete-log related assumption. These are the first security proofs for these schemes under assumptions related to the underlying one-way functions. Both results extend to establish security against impersonation under concurrent attack.

Alternating Refinement Relations

Abstract: Alternating transition systems are a general model for composite systems which allow the study of collaborative as well as adversarial relationships between individual system components. Unlike in labeled transition systems, where each transition corresponds to a possible step of the system (which may involve some or all components), in alternating transition systems, each transition corresponds to a possible move in a game between the components. In this paper, we study refinement relations between alternating transition systems, such as “Does the implementation refine the set A of specification components without constraining the components not in A?” In particular, we generalize the definitions of the simulation and trace containment preorders from labeled transition systems to alternating transition systems. The generalizations are called alternating simulation and alternating trace containment. Unlike existing refinement relations, they allow the refinement of individual components within the context of a composite system description. We show that, like ordinary simulation, alternating simulation can be checked in polynomial time using a fixpoint computation algorithm. While ordinary trace containment is PSPACE-complete, we establish alternating trace containment to be EXPTIME-complete. Finally, we present logical characterizations for the two preorders in terms of ATL, a temporal logic capable of referring to games between system components.

Coping During Public Service Delivery: A Conceptualization and Systematic Review of the Literature

Abstract: Frontline workers, such as teachers and social workers, often experience stress when delivering public services to clients, for instance because of high workloads. They adapt by coping, using such practices as breaking or bending rules for clients, or rationing services. Although coping is recognized as an important response to the problems of frontline work, the public administration field lacks a comprehensive view of coping. The first contribution of this article is therefore theoretical: conceptualizing coping during public service delivery and developing a coherent classification of coping. This is done via a systematic review of the literature from 1981 to 2014. The second contribution is empirical: via a systematic review of the literature from 1981–2014 this article provides a framework and analytical account of how coping during public service delivery has been studied since 1980. It highlights the importance of the type of profession (such as being a teacher or a police officer), the amount of workload, and the degree of discretion for understanding how frontline workers cope with stress. It also reveals that frontline workers often draw on the coping family “moving towards clients” revealing a strong tendency to provide meaningful public service to clients, even under stressful conditions. We conclude with an agenda for future studies, examining new theoretical, methodological and empirical opportunities to advance understanding of coping during public service delivery.

Method of using a clot capture coil

Abstract: A clot and foreign body removal device is described which comprises a catheter with at least one lumen. Located within the catheter is a clot capture coil that is connected to an insertion mandrel. In one embodiment, the clot capture coil is made out of a solid elastic or superelastic material which has shape memory, preferably nitinol. The elasticity or superelasticity of the coil allows it to be deformed within the catheter and to then reform its original coil configuration when the coil is moved outside of the catheter lumen. In another embodiment the coil is a biphasic coil which changes shape upon heating or passing an electric current. Once the coil configuration has been established, the coil can be used to ensnare and corkscrew a clot in a vessel. A clot is extracted from the vessel by moving the clot capture coil and catheter proximally until the clot can be removed or released into a different vessel that does not perfuse a critical organ. Foreign bodies are similarly captured by deploying the coil distal to the foreign body and moving the clot capture coil proximally until the foreign body is trapped within the coil. By removing the device from the body, the foreign material is also removed.