New Class of Continuous Wave Parametric Amplifiers

  • C. Headley
  • C.G. Jorgensen
  • Centanni J.
  • Chraplyvy A.
  • K. Brar
  • Mckinstrie C.
  • Radic S.
  • Raybon G.

A new class of fiber parametric amplifiers is demonstrated. Modulational instability coupling between optical pumps operating in the anomalous and normal dispersion regimes is used to achieve broad, flat CW parametric gain in excess of 40dB.

Parametric Amplifiers Driven by Two Pump Waves with Dissimilar Frequencies

  • Mckinstrie C.
  • Radic S.

Parametric amplifiers driven by two pump waves are studied numerically. For typical parameters, one can design an amplifier that produces uniform gain over a range of wavelengths that extends at least 33 nm on either side of the average pump wavelength.

Covering Indexes for Branching Path Expression Queries

  • Bohannon P.
  • J.F. Naughton
  • Korth H.
  • R. Kaushik

In this paper, we ask if the traditional relational query acceleration techniques of summary tables and covering indexes have analogs for branching path expression queries over tree- or graph-structured XML data.

Rapid Mixing

  • Winkler P.

In the past decade many proofs of tractability have involved showing that some Markov chain "mixes rapidly." We will do a fast tour of the highlights of Markov chain mixing, with a view toward answering -- or at least addressing -- the following questions: What is rapid mixing? How do ...

The Demand Matching Problem

  • A. Vetta
  • Shepherd F.

We examine formulations for the well-known b-matching problem in the presence of integer demands on the edges. A subset M of edges is feasible if for each node v, the total demand of edges in M incident to it is at most b. We examine the system of star inequalities ...

Generalized Processor Sharing Queues with Heterogeneous Traffic Classes

  • Borst S.
  • M. Mandjes
  • M. Van Uitert

We consider a queue fed by a mixture of light-tailed and heavy-tailed traffic. The two traffic classes are served in accordance with the Generalized Processor Sharing (GPS) discipline. GPS-based scheduling algorithms, such as Weighted Fair Queueing (WFQ), have emerged as an important mechanism for achieving service differentiation in integrated networks.

QoS with an Edge-Based Call Admission Control in IP Networks

  • Jeske D.
  • Samadi B.
  • Sohraby K.
  • Wang Y.
  • Zhang Q.

Central to the viability of providing traditional services over IP networks is the capability to deliver some level of end-to-end Quality of Service (QoS) to the applications and users. IP networks continue to struggle to migrate from an extremely cost effective best effort data service solution to revenue generating solutions ...

Markov Random Field Models of Multicasting in Tree Networks

  • Mitra P.
  • Ramanan K.
  • Sengupta A.
  • Ziedins I.

In this paper we analyze a model of a regular tree loss network that supports two types of calls -- unicast calls that require unit capacity on a single link, and multicast calls that require unit capacity on every link emanating from a node. We study the behaviour of the ...

Generalization of a Switch Access System Call Blocking Model

  • Jeske D.
  • Ji T.

A generalized blocking model is derived for a switch access system that was investigated in [1] by relaxing the assumption that the line unit is a cross bar switch. The need for this arises from the fact that in some switch access architectures, the number of servers in a server ...

Authenticated Transversal

  • A. Goodloe
  • C. Gunter
  • Hiller T.
  • M. Mcdougall
  • Mccann P.

In this paper we introduce a way to preserve end-to-end confidentiality while authenticating transversal of network elements with as many intervening review points as needed. Our technique associates the public-key-based authorization of a TCP connection request to a TLS connection. We show that this technique provides simpler setup and per-packet ...

Structure and Performance of the Direct Access File System (DAFS)

  • A. Fedorova
  • D. Gallatin
  • Gabber E.
  • J.S. Chase
  • K. Magoutis
  • M.I. Seltzer
  • R. Kisley
  • R. Wickremesinghe
  • S. Addetia

This paper outlines the fundamental performance characteristics of DAFS and presents experimental results from an open-source DAFS prototype to quantify the performance effects of its key distinguishing protocol features -- asynchronous direct-access operations and low-overhead bulk I/O. Our results characterize the class of workloads that benefit from DAFS, and show ...

Optical Layer Reconfigurability: Applications and Technologies

  • Levy D.

Architectures allowing for dynamic connectivity on the physical layer of an optical network and enabling component technologies will be discussed, and issues of control, scalability, and compliance to central office engineering limitations will be examined.

Performance Analysis of Channel Rate Selection Schemes in Systems with Tight Reuse

  • Balachandran K.
  • Ji T.
  • Kang J.

In GSM cellular networks, half-rate channels are specified as a bandwidth alternative to full-rate channels for the support of voice services under good conditions. In this paper, we propose and analyze channel rate selection algorithms upon initial call setup. Three different algorithms are considered: (a) Rate selection based on the ...

Slowing The Time-Fluctuating Mimo Channel

  • Chizhik D.

It has been reported [1], [2] that the number of transmitters that can be used in a MIMO system is limited by the coherence time of the channel. Furthermore, rapid channel fluctuations degrade the performance of feedback schemes that would otherwise increase the information throughput that may be achieved. These ...

Investigation of Si-doping and Impurity Incorporation Dependence on the Polarity of GaN by MBE

  • Cho A.
  • Ng H.

We have investigated the growth of Ga-polarity (0001) and N- polarity (000?1) Si-doped GaN on c-plane sapphire substrates by plasma-assisted Molecular Beam Epitaxy (MBE). For a given Si effusion cell temperature and under similar growth conditions, the Hall carrier concentration was found to be consistently higher for samples with N-polarity. ...

Combining Magnets and Dielectrics: Crystal BaO-Fe(sub2)O(sub03)-TiO(sub2) System

  • Siegrist T.
  • T.A. Vanderah

Observed phases in the Ba-Fe-Ti-O system are classified and described within the framework of close packed (Ba,O)/Oxygen layers, with the transition metals in either octahedral (titanium and iron) or tetrahedral (iron only) sites. This leads to new combinations of structural features intermediate to the barium hexaferrites and barium polytitanates. These ...

DCS1800 Base Station Receiver Integrated in 0.25 um CMOS

  • Boric-Lubecke O.
  • Jenshan Lin
  • Penny Gould

This paper describes the first CMOS chip implementation of a GSM base station receiver. This chip consists of two LNA's, switch, mixer, LO buffer amplifier/balun, and RF balun. A CMOS IF amplifier is packaged separately. The 0.25 um CMOS receiver, biased at 3 V, meets DCS1800 specifications and achieves better ...

Direct imaging of reverse-bias leakage through pure screw dislocations in GaN films grown by molecular beam epitaxy on GaN templates

  • B. Heting
  • Hsu J.
  • J.S. Speck
  • Manfra M.
  • R.J. Molnar

Pure screw dislocations are found to be the origin of excess reverse bias leakage in GaN films grown by molecular beam epitaxy on GaN templates. A scanning current-voltage microscope (SIVM) was used to map the spatial locations of leakage current on high quality GaN films under reverse bias. Two samples ...

A Poisson Limit for Buffer Overflow Probabilities

  • Cao J.
  • Ramanan K.

A key criterion in the design of high-speed networks is the probability that the buffer content exceeds a given threshold. We consider n independent identical traffic sources modelled as point processes, which are fed into a link with speed proportional to n. Under fairly general assumptions on the input processes ...

Optimizing View Queries in ROLEX to Support Navigable Result Trees

  • Bohannon P.
  • Ganguly S.
  • Korth H.
  • P. Shenoy
  • Perinkulam S.

This paper presents the architecture of ROLEX, including its model of query execution and the query optimizer. We demonstrate with a performance study the advantages of the ROLEX approach and the importance of optimizing query execution for navigation.