Contention Resolution with Constant Expected Delay

  • Goldberg L.
  • Mackenzie P.
  • Paterson M.
  • Srinivasan A.

We study contention resolution in a multiple-access channel such as the Ethernet channel. In the model that we consider, n users generate messages for the channel according to a probability distribution. Raghavan and Upfal have given a protocol in which the expected delay (time to get serviced) of every message ...

Largest Weighted Delay First Scheduling Large Deviations and Optimality

  • Ramanan K.
  • Stolyar A.

We consider a single server system with N input flows. We assume that each flow has stationary increments and satisfies a sample path large deviation principle. We introduce the Largest Weighted Delay First (LWDF) queueing discipline associated with any given weight vector alpha = (alpha sub 1,...,alpha sub N). We ...

Policy Disputes in Path-Vector Protocols

  • Griffin T.
  • Shepherd F.
  • Wilfong G.

The Border Gateway Protocol, BGP, is currently the only interdomain routing protocol employed on the Internet. As required of any interdomain protocol, BGP allows policy-based metrics to override distance-based metrics and enables each autonomous system to independently define its routing policies with little or no global coordination. Varadhan et al. ...

Time-Varying Network Tomography: Router Link Data

  • Cao J.
  • Davis R.
  • Vander Wiel S.
  • Yu B.

The origin-destination (OD) traffic matrix in local area networks is useful for solving problems in network design, routing, configuration debugging, and monitoring. Directly measuring this matrix is not usually feasible but less informative link measurements are easy to obtain. This work studies the inference of OD byte counts from link ...

Dynamic Images of Plasma Processes: Use of Orthogonal Polynomial Functions for Endpoint Detection During Plasma Etching of Patterned Wafers

  • Downey S.
  • Layadi N.
  • Rietman E.

We show that by using various in situ etch process signals (e.g., reflected power, induced dc bias) as the coefficients in an orthogonal polynomial expansion we can determine endpoint for processes which heretofore have not had strong endpoint signals. The technique essentially amplifies weak signals. We have used the orthogonal ...

Mapping of Wafer Profile to Plasma Processing Conditions: Forward and Reverse Maps

  • Lane J.
  • Layadi N.
  • Lee J.
  • Rietman E.

Recent work by Vyvoda et al. (1998) and Lane et al. (1999) (among others) have resulted in phenomonological forward models that describe the profile of the structures from an etch process. In this paper, we quantify the reverse model and show that it is possible to use the profile information ...

Improved Continuous Wave Operation of Quantum Cascade Lasers with Epitaxial-Side Heat-Sinking

  • Baillargeon J.
  • Capasso F.
  • Cho A.
  • Chu S.
  • Gmachl C.
  • Hutchinson A.
  • Sergent A.
  • Sivco D.
  • Tredicucci A.

First results on the epilayer-side mounting of quantum cascade (QC) lasers are presented. Operated in continuous wave (cw) mode, these lasers are superior to substrate-bonded devices. The maximum cw temperatures is raised by 20K (up to 175K), and at comparable heat sink temperatures the performance with respect to threshold current, ...

Reduction of Crosstalk in Semiconductor Optical Amplifiers by Amplifying Dispersed WDM Signals (7x20 Gb/s)

  • Mikkelsen B.
  • Raybon G.

We show that placing semiconductor optical amplifiers at positions in the fiber network where the signals are highly dispersed can increase the dynamic range of the amplifiers considerably. We demonstrate a fivefold increase in the dynamic range in a WDM experiment at channel rates of 20 Gbit/s (7x20 Gbit/s).

Transport and Magnetoresistance in Low Carrier Density Ferromagnets

  • Littlewood P.

In metallic magnets, scattering from magnetic fluctuations above and near T sub c may provide a substantial contribution to the electrical p(T). However, this effect is usually small because the dominant fluctuations are near q~0, which does not produce substantial backscattering across the Fermi surface unless 2k sub F is ...

Remarks on Multilevel Bases for Divergence-Free Finite Elements

  • Oswald P.

The connection between the multilevel factorization method recently proposed by Sarin and Sameh for solving mixed discretizations of the Stokes equation and hierarchical basis preconditioners is established. For the 2D triangular Taylor-Hood element, a local basis of divergence-free velocities and a preconditioning method are proposed that could be useful in ...

Smart Dynamic Wavelength Equalizer with On-Chip Spectrum Analyzer

  • Cappuzzo M.
  • Doerr C.
  • Gomez L.
  • Laskowski E.
  • Paunescu A.
  • Schiffer P.
  • Stulz L.

A fully automated dynamic wavelength equalizer with fast feedback is presented, consisting of a planar optical circuit made in silica and a minimal amount of secondary elements. An on-chip monitor and a single optical diode serve as a low-cost, fast, built-in optical spectrum analyzer, used to feedback control the device. ...

Inelastic Light Scattering by Collective Excitations in the Fractional Quantum Hall Regime

  • Dennis B.
  • Eriksson M.
  • Kang M.
  • Pfeiffer L.
  • Pinczuk A.
  • West K.

We report an inelastic light scattering study of long wavelength collective gap excitations of fractional quantum Hall (FQH) states at nu = p over 2p+1 for 1/3 <= nu <= 2/3. The nu-dependence of the gap energy suggests a collapse of the collective excitation gap near nu = 1/2. In ...

Inelastic Light Scattering in Electron Wonderland: Quantum Liquids and Phase Transitions

  • Pinczuk A.

The inelastic light scattering method has been used extensively to study collective excitations of low dimensional electron systems in semiconductor quantum structures. This communication presents very short summary of some recent light scattering research in high quality two-dimensional systems. The studies considered here explore effects. The highlights are in three ...

High Power and Tunable Single-Mode Quantum Cascade Lasers

  • Baillargeon J.
  • Capasso F.
  • Cho A.
  • Gmachl C.
  • Hutchinson A.
  • Sivco D.
  • Tredicucci A.

Quantum cascade (QC) lasers are a fundamentally new semiconductor laser source designed by methods of "bandstructure engineering" and realized by molecular beam epitaxy (MBE). One of their most intriguing features is the cascading scheme, which results in the lasers' intrinsic potential for high optical output power. QC-lasers with varying numbers, ...

Optical Pulse Compression Schemes that Use Nonlinear Bragg Gratings

  • Eggleton B.
  • Lenz G.
  • Litchinitser N.

Nonlinear optical pulse compression of picosecond pulses typically requires long lengths of optical fiber and multiple components Periodic structures, such as fiber Bragg gratings, are highly dispersive, at wavelengths outside of the photonic bandgap. This implies that such gratings can be used as very short all-fiber compressors. In this paper, ...

A Method for Reducing the Variation in "On" Resistance of a MOS Sampling Switch

  • Ong A.
  • Prodanov V.
  • Tarsia M.

Variation in the "on" resistance of a MOS sampling switch can introduce distortion into the front end of a switched-capacitor filter or analog-to-digital converter. We review three methods commonly used to linearize the resistance of a MOS switch and propose a new technique that addresses their limitations. A practical method ...

Structure of Epitaxial Gd203 Films Grown on GaAs (100)

  • Hong M.
  • Kortan A.
  • Kwo J.
  • Mannaerts J.

Single crystal Gd sub 2 O sub 3 films were grown epitaxially on GaAs (100) substrate. From the single crystal momentum-space analysis of the x-ray diffraction on four different samples 185, 45, 25 and 18 angstroms thick, an isomorphous Mn sub 2 O sub 3 cubic structure is identified. The ...

The Multiclass GI/PH/N Queue in the Halfin-Whitt Regime

  • Puhalskii A.
  • Reiman M.

We consider a multiserver queue in the heavy-traffic regime introduced and studied by Halfin and Whitt who investigated the case of a single customer class with exponentially distributed service times. Our purpose is to extend their analysis to a system with multiple customer classes, priorities, and phase-type service distributions. We ...

Trends in Digital Signal Processors

  • Mujtaba S.

To facilitate the implementation of complex signal processing algorithms, future DSPs will be required to deliver higher performance and ease-of-programmability without compromising power dissipation and code density. To meet these conflicting requirements, several architectures have been proposed such as EPIC, VLIW, and Superscalar. In this paper, we chart the evolution ...

Texture Development of Blanket Electroplated Copper Films

  • Brown W.
  • Gross M.
  • Lingk C.

The transition from sputtered Al to electroplated Cu interconnects for future microelectronic devices has led to an interest in understanding the relationships between the microstructure and texture of Cu that might impact electrical performance, similar to what has been done for Al. Electroplated Cu undergoes a recrystallization at room temperature ...