FLIP - Multiobjective Fuzzy Linear Programming Package

FLIP (Fuzzy LInear Programming) is a package designed to help in analysis of multiobjective linear programming (MOLP) problems in an uncertain environment. The uncertainty of data is modeled by L-R type fuzzy numbers. They can appear in the objective functions as well as on the both sides of the constraints. The input data to the FLIP package include the characteristics of the analyzed fuzzy MOLP problem, i.e., the number of criteria, constraints and decision variables, fuzzy cost coefficients for every objective and fuzzy coefficients of LHS and RHS for all constraints. The data loading is supported by a graphical presentation of fuzzy coefficients. The calculation is preceded by a transformation of the fuzzy MOLP problem into a multiobjective linear fractional program. It is then solved with an interactive method using a linear programming procedure as the only optimiser. In every iteration, one gets a series of solutions that are presented very clearly in a graphical and numerical form. In FLIP, interaction with the user takes place at two levels: first, when safety parameters have to be defined in the transformation phase, and second, when the associate deterministic problem is solved. The package is written in TURBO-Pascal and can be used on microcomputers compatible with IBM-PC XT/AT with hard disc and a graphic card

Semiconductor optical amplifiers and raman amplification for 1310-nm wavelength division multiplexed transmission

We investigate the utilization of semiconductor optical amplifiers (SOAs) and quantum-dot laser-based Raman amplifiers in high-capacity dense wavelength division multiplexed (DWDM) 1310-nm transmission systems. Performed simulations showed that in a 10×40  Gbit/s 10×40  Gbit/s system, the utilization of a single Raman amplifier in a back-propagation scheme can extend the maximum error-free (bit error rate <10 −9 <10−9 ) transmission distance by approximately 25 km in comparison with the same system utilizing only an SOA used as a preamplifier. We successfully applied a Raman amplifier in an 8×2×40  Gbit/s 8×2×40  Gbit/s 1310-nm polarization multiplexed (PolMux) DWDM transmission over 25 km. Conducted experiments showed that the utilization of a Raman amplifier in this system leads to 4-dB improvement of the average channel sensitivity in comparison to the same system utilizing SOAs. This sensitivity improvement can be translated into a higher power budget. Moreover, lower input optical power in a system utilizing a Raman amplifier reduces the four-wave mixing interactions. The obtained results prove that Raman amplification can be successfully applied in 1310-nm high-capacity transmission systems, e.g., to extend the reach of 400G and 1T Ethernet systems

A large-scale R-matrix calculation for electron-impact excitation of the Ne2+^{2+} O-like ion

The five J$\Pi$ levels within a $np^2$ or $np^4$ ground state complex provide an excellent testing ground for the comparison of theoretical line ratios with astrophysically observed values, in addition to providing valuable electron temperature and density diagnostics. The low temperature nature of the line ratios ensure that the theoretically derived values are sensitive to the underlying atomic structure and electron-impact excitation rates. Previous R-matrix calculations for the Ne$^{2+}$ O-like ion exhibit large spurious structure in the cross sections at higher electron energies, which may affect Maxwellian averaged rates even at low temperatures. Furthermore, there is an absence of comprehensive excitation data between the excited states that may provide newer diagnostics to compliment the more established lines discussed in this paper. To resolve these issues, we present both a small scale 56-level Breit-Pauli (BP) calculation and a large-scale 554 levels R-matrix Intermediate Coupling Frame Transformation (ICFT) calculation that extends the scope and validity of earlier JAJOM calculations both in terms of the atomic structure and scattering cross sections. Our results provide a comprehensive electron-impact excitation data set for all transitions to higher $n$ shells. The fundamental atomic data for this O-like ion is subsequently used within a collisional radiative framework to provide the line ratios across a range of electron temperatures and densities of interest in astrophysical observations.Comment: 17 pages, 8 figure

Mapping and Spectroscopy of the Planetary Nebula NGC 7009 in the Visual and Infrared

NGC 7009 is a fascinating example of a high excitation, elliptical planetary nebula (PN) containing circum-nebular rings, and FLIERs and jets along the major axis. We present visual spectroscopy along multiple position angles through the nucleus, taken with the Observatorio Astronomico Nacional (Mexico); mid-infrared (MIR) spectroscopy and imaging acquired using the Infrared Space Observatory (ISO) and Spitzer Space Telescope (SST), and narrow band imaging obtained using the Hubble Space Telescope (HST). The data show that the mid-infrared (MIR) continuum is dominated by a broad ~ 100K continuum, and a strong excess attributable to crystalline silicate emission. The primary peaks in this excess are similar to those observed in Forsterite and clino- and ortho-enstatite. We use the ground-based spectroscopy, and ratioing of HST images to investigate the presence of shocks in the ansae and interior envelope. It is concluded that line ratios in the ansae may be partially consistent with shock excitation, although these features are primarily dominated by photo-ionisation. We also note evidence for shock excitation at the limits of the interior elliptical shell, and for multiple bow-shock structures centered upon the ansae.Comment: 22 pages, 19 figures. Accepted for publication in MNRAS. 52 pages in arXi

The raman amplifier in low-complexity PolMux DWDM 1310 nm transmission

In this paper, we experimentally investigate the impact of the Raman amplifier on the transmission quality in the high capacity and low complexity polarization multiplexed and dense wavelength division multiplexed transmission system in the 1310 nm wavelength domain. We compare its performance with the same system utilizing the semiconductor optical amplifier. Conducted experiments show that in the presented 1310 nm 8×2×40 Gbit/s transmission system, with the transmission line consisting of 25 km standard single mode fibre, the Raman amplifier can be successfully applied and its utilization leads to the 4 dB improvement of the average channel sensitivity in comparison with the system with a semiconductor optical amplifie

Up to 112 Gbit/s single wavelength channel transmission in the 1310 nm wavelength domain

In this article, we present up to 112 Gbit/s single wavelength channel on-off keying transmission in the 1310-nm wavelength domain utilizing polarization multiplexing over distances 25–38 km of standard single mode fiber. Excellent operation of the system is demonstrated. The proposed solution can be successfully utilized in data communications transmission. Keywords: optical communications; semiconductor optical amplifier; polarization division multiplexing; 1310 nm; data communicatio

The raman amplifier in low-complexity PolMux DWDM 1310 nm transmission

In this paper, we experimentally investigate the impact of the Raman amplifier on the transmission quality in the high capacity and low complexity polarization multiplexed and dense wavelength division multiplexed transmission system in the 1310 nm wavelength domain. We compare its performance with the same system utilizing the semiconductor optical amplifier. Conducted experiments show that in the presented 1310 nm 8×2×40 Gbit/s transmission system, with the transmission line consisting of 25 km standard single mode fibre, the Raman amplifier can be successfully applied and its utilization leads to the 4 dB improvement of the average channel sensitivity in comparison with the system with a semiconductor optical amplifie

The Pareto Envelope-based Selection Algorithm for Multiobjective Optimization

. We introduce a new multiobjective evolutionary algorithm called PESA (the Pareto Envelope-based Selection Algorithm), in which selection and diversity maintenance are controlled via a simple hyper-grid based scheme. PESA&apos;s selection method is relatively unusual in comparison with current well known multiobjective evolutionary algorithms, which tend to use counts based on the degree to which solutions dominate others in the population. The diversity maintenance method is similar to that used by certain other methods. The main attraction of PESA is the integration of selection and diversity maintenance, whereby essentially the same technique is used for both tasks. The resulting algorithm is simple to describe, with full pseudocode provided here and real code available from the authors. We compare PESA with two recent strongperforming MOEAs on some multiobjective test problems recently proposed by Deb. We find that PESA emerges as the best method overall on these problems..