Bell Labs

About: Bell Labs is a based out in . It is known for research contribution in the topics: Laser & Optical fiber. The organization has 36499 authors who have published 59862 publications receiving 3190823 citations. The organization is also known as: Bell Laboratories & AT&T Bell Laboratories.

Discrete Resistance Switching in Submicrometer Silicon Inversion Layers: Individual Interface Traps and Low-Frequency ( 1 f ?) Noise

Abstract: Resistance fluctations in submicrometer narrow Si inversion layers are studied over a wide range of temperatures and electron concentrations. Thermally activated switching on and off of discrete resistance increments is observed, caused by the capture and emission of individual electrons at strategically located scatterers (interface traps). The traps have a broad distribution of activation energies, as assumed in accounting for $\frac{1}{f}$ noise in larger devices.

Magnetization and Critical Supercurrents

Abstract: The magnetization in high-fteld superconductors has been investigated using tubular samples. When the sample assumes a critical state, wherein every region of the sample carries critical current density J(B) determined only by the local magnetic field B, the magnetization can be predicted quantitatively from the critical current density J(B). Using observed magnetization data, a critical current density relation alpha /J = B/sub 0/ + B is deduced for Nb/sub 3/Sn and 3Nb-Zr. Alpha is a direct measure of the current carrying capacity of a sample, and B/sub 0/ coincides approximately with the thermodynamic critical field of the material. Since this relation implies JB = alpha = const for B >> B/sub 0/, the Lorertz force plays an important role in determining the critical current density. (auth)

Augmented encrypted key exchange: a password-based protocol secure against dictionary attacks and password file compromise

Abstract: The encrypted key exchange (EKE) protocol is augmented so that hosts do not store cleartext passwords. Consequently, adversaries who obtain the one-way encrypted password file may (i) successfully mimic (spoof) the host to the user, and (ii) mount dictionary attacks against the encrypted passwords, but cannot mimic the user to the host. Moreover, the important security properties of EKE are preserved—an active network attacker obtains insufficient information to mount dictionary attacks. Two ways to accomplish this are shown, one using digital signatures and one that relies on a family of commutative one-way functions.

Human factors and behavioral science: Textons, the fundamental elements in preattentive vision and perception of textures

Abstract: Recent research in texture discrimination has revealed the existence of a separate “preattentive visual system” that cannot process complex forms, yet can, almost instantaneously, without effort or scrutiny, detect differences in a few local conspicuous features, regardless of where they occur. These features, called “textons”, are elongated blobs (e.g., rectangles, ellipses, or line segments) with specific properties, including color, angular orientation, width, length, binocular and movement disparity, and flicker rate. The ends-of-lines (terminators) and crossings of line segments are also textons. Only differences in the textons or in their density (or number) can be preattentively detected while the positional relationship between neighboring textons passes unnoticed. This kind of positional information is the essence of form perception, and can be extracted only by a time-consuming and spatially restricted process that we call “focal attention”. The aperture of focal attention can be very narrow, even restricted to a minute portion of the fovea, and shifting its locus requires about 50 ms. Thus preattentive vision serves as an “early warning system” by pointing out those loci of texton differences that should be attended to. According to this theory, at any given instant the visual information intake is relatively modest.

All from One, One for All: on Model Checking Using Representatives

Abstract: Checking that a given finite state program satisfies a linear temporal logic property is suffering in many cases from a severe space and time explosion. One way to cope with this is to reduce the state graph used for model checking. We define an equivalence relation between infinite sequences, based on infinite traces such that for each equivalence class, either all or none of the sequences satisfy the checked formula. We present an algorithm for constructing a state graph that contains at least one representative sequence for each equivalence class. This allows applying existing model checking algorithms to the reduced state graph rather than on the larger full state graph of the program. It also allows model checking under fairness assumptions, and exploits these assumptions to obtain smaller state graphs. A formula rewriting technique is presented to allow coarser equivalence relation among sequences, such that less representatives are needed.