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1 – 10 of over 10000
Article
Publication date: 11 October 2011

Gurmeet Kaur, M.L. Singh and M.S. Patterh

Fiber nonlinearities are anticipated to impose transmission limitations due to the enhanced total interaction length in long‐haul dense wavelength division multiplexing…

271

Abstract

Purpose

Fiber nonlinearities are anticipated to impose transmission limitations due to the enhanced total interaction length in long‐haul dense wavelength division multiplexing (DWDM) optical transmission systems. The purpose of this paper is to analytically study the combined effect of stimulated Raman scattering (SRS) and fourwave mixing (FWM) in the presence of amplified spontaneous emission (ASE) noise generated by erbium‐doped fiber amplifiers (EDFAs).

Design/methodology/approach

The paper presents analytical analysis of DWDM optical transmission systems in the presence of two significant fiber nonlinearities (SRS and FWM).

Findings

Simple expressions are derived to study the dependence of signal‐to‐noise ratio (SNR) on the amplifier spacing between two consecutive amplifiers.

Originality/value

The authors have analytically studied the combined effect of SRS and FWM in the presence of ASE noise generated by EDFAs. The novelty of the work is that it has considered all the three factors simultaneously and the expressions are derived for calculation of SNR.

Details

Journal of Engineering, Design and Technology, vol. 9 no. 3
Type: Research Article
ISSN: 1726-0531

Keywords

Article
Publication date: 1 February 1986

J.A. Neff

A major limitation to achieving significant speed increases in VLSI lies in the metallic interconnects. They are costly not only from the charge transport standpoint but…

Abstract

A major limitation to achieving significant speed increases in VLSI lies in the metallic interconnects. They are costly not only from the charge transport standpoint but also from capacitive loading effects. The Defense Advanced Research Projects Agency, in pursuit of fifth generation supercomputing, is investigating alternatives to the VLSI metallic interconnects, especially the use of optical techniques to transport the information between chips or between boards. As the on‐chip performance of VLSI continues to improve via the scale‐down of the logic elements, the problems associated with transferring data off and onto the chip become more severe. The use of optical carriers to transfer the information within the computer is very appealing from several viewpoints. Besides the potential for gigabit propagation rates, the conversion from electronics to optics conveniently provides a decoupling of the various circuits from one another. Significant gains will also be realised in reducing cross‐talk between the metallic routings, and the interconnects need no longer be constrained to the plane of the VLSI chip. In addition, optics can offer an increased programming flexibility for restructuring the interconnect network.

Details

Microelectronics International, vol. 3 no. 2
Type: Research Article
ISSN: 1356-5362

Article
Publication date: 30 March 2010

Gurmeet Kaur, M.L. Singh and M.S. Patterh

The current generation of light wave systems benefit from increased transmission distance by using optical amplification and increased capacity by using dense wavelength…

Abstract

Purpose

The current generation of light wave systems benefit from increased transmission distance by using optical amplification and increased capacity by using dense wavelength division multiplexing (DWDM) technology. The reach of present systems is limited by the noise contributed by the used amplifiers, combined with nonlinear effects from transmission. This paper aims to address these issues.

Design/methodology/approach

The nature and extent of degradations in the optical DWDM systems due to these limiting factors have been discussed in this paper.

Findings

It has been learnt that stimulated Raman scattering (SRS), four wave mixing (FWM) and amplified spontaneous emission (ASE) are the important factors in optical DWDM systems. These factors limit the system capacity of the transmission systems drastically.

Originality/value

It can be concluded from the discussion that while designing an efficient DWDM system, an optimization of the channel separation and the amplifier separation is required to minimize the nonlinear effects (FWM and SRS) along with the ASE noise introduced by inline optical amplifications.

Details

Journal of Engineering, Design and Technology, vol. 8 no. 1
Type: Research Article
ISSN: 1726-0531

Keywords

Article
Publication date: 1 October 2004

Nick Green

While working with clients in the last years of his life, Gordon Pask produced an axiomatic scheme for his Interactions of Actors Theory which is a development of his well…

Abstract

While working with clients in the last years of his life, Gordon Pask produced an axiomatic scheme for his Interactions of Actors Theory which is a development of his well known Conversation Theory. These axioms are interpretable as a general theory of self‐organisation and are discussed as characteristic of field concurrence and as part of the second‐order cybernetics canon. An application to population density is reported supported by both kinematic and kinetic simulation. Implications for cardiovascular anti‐coagulation therapy and planetary evolution are discussed.

Details

Kybernetes, vol. 33 no. 9/10
Type: Research Article
ISSN: 0368-492X

Keywords

Article
Publication date: 21 August 2009

Anas N. Al‐Rabadi

The purpose of this paper is to introduce new non‐classical implementations of neural networks (NNs). The developed implementations are performed in the quantum, nano, and…

Abstract

Purpose

The purpose of this paper is to introduce new non‐classical implementations of neural networks (NNs). The developed implementations are performed in the quantum, nano, and optical domains to perform the required neural computing. The various implementations of the new NNs utilizing the introduced architectures are presented, and their extensions for the utilization in the non‐classical neural‐systolic networks are also introduced.

Design/methodology/approach

The introduced neural circuits utilize recent findings in the quantum, nano, and optical fields to implement the functionality of the basic NN. This includes the techniques of many‐valued quantum computing (MVQC), carbon nanotubes (CNT), and linear optics. The extensions of implementations to non‐classical neural‐systolic networks using the introduced neural‐systolic architectures are also presented.

Findings

Novel NN implementations are introduced in this paper. NN implementation using the general scheme of MVQC is presented. The proposed method uses the many‐valued quantum orthonormal computational basis states to implement such computations. Physical implementation of quantum computing (QC) is performed by controlling the potential to yield specific wavefunction as a result of solving the Schrödinger equation that governs the dynamics in the quantum domain. The CNT‐based implementation of logic NNs is also introduced. New implementations of logic NNs are also introduced that utilize new linear optical circuits which use coherent light beams to perform the functionality of the basic logic multiplexer by utilizing the properties of frequency, polarization, and incident angle. The implementations of non‐classical neural‐systolic networks using the introduced quantum, nano, and optical neural architectures are also presented.

Originality/value

The introduced NN implementations form new important directions in the NN realizations using the newly emerging technologies. Since the new quantum and optical implementations have the advantages of very high‐speed and low‐power consumption, and the nano implementation exists in very compact space where CNT‐based field effect transistor switches reliably using much less power than a silicon‐based device, the introduced implementations for non‐classical neural computation are new and interesting for the design in future technologies that require the optimal design specifications of super‐high speed, minimum power consumption, and minimum size, such as in low‐power control of autonomous robots, adiabatic low‐power very‐large‐scale integration circuit design for signal processing applications, QC, and nanotechnology.

Details

International Journal of Intelligent Computing and Cybernetics, vol. 2 no. 3
Type: Research Article
ISSN: 1756-378X

Keywords

Content available
Article
Publication date: 30 March 2010

Theo C. Haupt

296

Abstract

Details

Journal of Engineering, Design and Technology, vol. 8 no. 1
Type: Research Article
ISSN: 1726-0531

Content available
Article
Publication date: 11 October 2011

Theo C. Haupt

287

Abstract

Details

Journal of Engineering, Design and Technology, vol. 9 no. 3
Type: Research Article
ISSN: 1726-0531

Article
Publication date: 20 March 2017

Zongwen Fu, Matthias Freihart, Tobias Schlordt, Tobias Fey, Torsten Kraft, Peter Greil and Nahum Travitzky

This study aims to achieve the fabrication of three-dimensional core-shell filament-based lattice structures by means of robocasting combined with co-extrusion. For core…

Abstract

Purpose

This study aims to achieve the fabrication of three-dimensional core-shell filament-based lattice structures by means of robocasting combined with co-extrusion. For core and shell materials, colloidal gels composed of submicron carbon and alumina powders were developed, respectively. Simultaneously, the co-extrusion process was also studied by numerical simulation to investigate the feed pressure-dependent wall thickness.

Design/methodology/approach

Significant differences in the rheological behavior of the carbon and alumina gels were observed because of differences of the particle morphology and surface chemistry of the carbon and alumina powders. Precise control over the cross-sectional diameter of the core and shell green state elements was achieved by alteration of the feed pressures used during co-extrusion.

Findings

After subsequent thermal treatment in an oxidizing atmosphere (e.g. air), in which the carbon core was oxidized and burned out, lattice structures formed of hollow filaments of predetermined wall thickness were manufactured; additionally, C-Al2O3 core-shell filament lattice structures could be derived after firing in an argon atmosphere.

Originality/value

Green lattice truss structures with carbon core and alumina shell filaments were successfully manufactured by robotically controlled co-extrusion. As feedstocks carbon and alumina gels with significantly different rheological properties were prepared. During co-extrusion, the core paste exhibited a much higher viscosity than the shell paste, which benefited the co-extrusion process. Simultaneously, the core and shell diameters were exactly controlled by core and shell feed pressures and studied by numerical simulation. The experimentally and numerically derived filament wall thickness showed qualitative agreement with each other; with decreasing core pressure during co-extrusion, the wall thickness increased.

Details

Rapid Prototyping Journal, vol. 23 no. 2
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 14 January 2014

Malathy Batumalay, F. Ahmad, Asiah Lokman, A.A. Jasim, Sulaiman Wadi Harun and H. Ahmad

A simple tapered plastic optical fiber (POF) sensor is proposed and demonstrated for measurement of uric acid concentrations in de-ionized water. The paper aims to discuss…

Abstract

Purpose

A simple tapered plastic optical fiber (POF) sensor is proposed and demonstrated for measurement of uric acid concentrations in de-ionized water. The paper aims to discuss these issues.

Design/methodology/approach

The sensor operates based on intensity modulation technique as the tapered POF probe which was coated by a single walled carbon nonotubes polyethylene oxide (SWCNT-PEO) composite is immersed into the uric acid solution. The probe was fabricated using an etching method and has a waist diameter of 0.46 mm and tapering length of 10 mm.

Findings

As the concentration varies from 0 to 500 ppm, the output voltage of the sensor increases linearly from 6.13 to 7.35 mV with a sensitivity of 0.0023 mV/% and a linearity of more than 97.20 percent. The SWCNT-PEO composite coating increases the sensitivity of the proposed sensor due to the effective cladding refractive index, which increases with the coating and thus allows more light to be transmitted from the tapered fiber.

Originality/value

This is the first demonstration of the tapered POF sensor for measurement of uric acid concentrations in de-ionized water.

Details

Sensor Review, vol. 34 no. 1
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 1 March 2022

Kriparaj K.G., Roy V. Paul, Tide P.S. and Biju N.

The purpose of this paper is to conduct an experimental investigation on the shock cell structure of jets emanating from a four-lobed corrugated nozzle using Schlieren…

Abstract

Purpose

The purpose of this paper is to conduct an experimental investigation on the shock cell structure of jets emanating from a four-lobed corrugated nozzle using Schlieren imaging technique.

Design/methodology/approach

The Schlieren images were captured for seven different nozzle pressure ratios (NPR = 2, 3, 4, 5, 6, 7 and 8) and compared with the shock cell structure of a round nozzle with an identical exit area. The variation in the length of the shock cell, width of boundary interaction between adjacent shock cells, maximum width of first shock cell, Mach disk position and diameter for different NPR was measured from the Schlieren images and analysed.

Findings

A three-layer shock net observed in the jet emanating from the four-lobed corrugated nozzle is a novel concept in the field of under-expanded jet flows. A shock net represents interconnected layers of shock cells developed because of the interaction between the core and peripheral shock waves in a jet emanating from a corrugated lobed nozzle. Also, the pattern of shock net is different while taking Schlieren images across the groove and lobe sections. Thus, the shock net emerging from a corrugated lobed nozzle varies azimuthally and primarily depends on the nozzle exit cross section. The length of the shock cell, width of boundary interaction between adjacent shock cells, maximum width of first cell, Mach disk position and diameter were found to exhibit increasing trend with NPR.

Originality/value

A novel concept of interconnected layers of shock waves defined as “shock net” developed from a single jet emanating from a four-lobed corrugated nozzle was observed.

Details

Aircraft Engineering and Aerospace Technology, vol. 94 no. 7
Type: Research Article
ISSN: 1748-8842

Keywords

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