Mode-division-multiplexed 3x112-Gb/s DP-QPSK transmission over 80 km few-mode fiber with inline MM-EDFA and blind DSP

We show transmission of a 3x112-Gb/s DP-QPSK mode-division-multiplexed signal up to 80km, with and without multi-mode EDFA, using blind 6x6 MIMO digital signal processing. We show that the OSNR-penalty induced by mode-mixing in the multi-mode EDFA is negligible.

Phase noise tolerance study in coherent optical circular QAM transmissions with Viterbi- Viterbi carrier phase estimation

We present a performance evaluation of a non-conventional approach to implement phase noise tolerant optical systems with multilevel modulation formats. The performance of normalized Viterbi-Viterbi carrier phase estimation (V-V CPE) is investigated in detail for circular m-level quadrature amplitude modulation (C-mQAM) signals. The intrinsic property of C-mQAM constellation points with a uniform phase separation allows a straightforward employment of V-V CPE without the need to adapt constellation. Compared with conventional feed-forward CPE for square QAM signals, the simulated results show an enhanced tolerance of linewidth symbol duration product (ΔvTs) at a low sensitivity penalty by using feed-forward CPE structure with C-mQAM. This scheme can be easily upgraded to higher order modulations without inducing considerable complexity.

Risk Measures for Classical and Perturbed Risk Processes - a Survey

2000 Mathematics Subject Classification: 60B10, 60G17, 60G51, 62P05.

Evaluation of 100G DP-QPSK long-haul transmission performance using second order co-pumped Raman laser based amplification

We present, for the first time, a detailed investigation of the impact of second order co-propagating Raman pumping on long-haul 100G WDM DP-QPSK coherent transmission of up to 7082 km using Raman fibre laser based configurations. Signal power and noise distributions along the fibre for each pumping scheme were characterised both numerically and experimentally. Based on these pumping schemes, the Q factor penalties versus co-pump power ratios were experimentally measured and quantified. A significant Q factor penalty of up to 4.15 dB was observed after 1666 km using symmetric bidirectional pumping, compared with counter-pumping only. Our results show that whilst using co-pumping minimises the intra-cavity signal power variation and amplification noise, the Q factor penalty with co-pumping was too great for any advantage to be seen. The relative intensity noise (RIN) characteristics of the induced fibre laser and the output signal, and the intra-cavity RF spectra of the fibre laser are also presented. We attribute the Q factor degradation to RIN induced penalty due to RIN being transferred from the first order fibre laser and second order co-pump to the signal. More importantly, there were two different fibre lasing regimes contributing to the amplification. It was random distributed feedback lasing when using counter-pumping only and conventional Fabry-Perot cavity lasing when using all bidirectional pumping schemes. This also results in significantly different performances due to different laser cavity lengths for these two classes of laser.

Enabling long journeys in electric vehicles:design and demonstration of an infrastructure location model

This research develops a methodology and model formulation which suggests locations for rapid chargers to help assist infrastructure development and enable greater battery electric vehicle (BEV) usage. The model considers the likely travel patterns of BEVs and their subsequent charging demands across a large road network, where no prior candidate site information is required. Using a GIS-based methodology, polygons are constructed which represent the charging demand zones for particular routes across a real-world road network. The use of polygons allows the maximum number of charging combinations to be considered whilst limiting the input intensity needed for the model. Further polygons are added to represent deviation possibilities, meaning that placement of charge points away from the shortest path is possible, given a penalty function. A validation of the model is carried out by assessing the expected demand at current rapid charging locations and comparing to recorded empirical usage data. Results suggest that the developed model provides a good approximation to real world observations, and that for the provision of charging, location matters. The model is also implemented where no prior candidate site information is required. As such, locations are chosen based on the weighted overlay between several different routes where BEV journeys may be expected. In doing so many locations, or types of locations, could be compared against one another and then analysed in relation to siting practicalities, such as cost, land permission and infrastructure availability. Results show that efficient facility location, given numerous siting possibilities across a large road network can be achieved. Slight improvements to the standard greedy adding technique are made by adding combination weightings which aim to reward important long distance routes that require more than one charge to complete.

Powertrain optimisation in a hybrid electric bus

This paper describes the use of a formal optimisation procedure to optimise a plug-in hybrid electric bus using two different case studies to meet two different performance criteria; minimum journey cost and maximum battery life. The approach is to choose a commercially available vehicle and seek to improve its performance by varying key design parameters. Central to this approach is the ability to develop a representative backward facing model of the vehicle in MATLAB/Simulink along with appropriate optimisation objective and penalty functions. The penalty functions being the margin by which a particular design fails to meet the performance specification. The model is validated against data collected from an actual vehicle and is used to estimate the vehicle performance parameters in a model-in-the-loop process within an optimisation routine. For the purposes of this paper, the journey cost/battery life over a drive cycle is optimised whilst other performance indices are met (or exceeded). Among the available optimisation methods, Powell's method and Simulated Annealing are adopted. The results show this method as a valid alternative modelling approach to vehicle powertrain optimisation. © 2012 IEEE.

A cost-effective steam-driven RO plant for brackish groundwater

Desalination is a costly means of providing freshwater. Most desalination plants use either reverse osmosis (RO) or thermal distillation. Both processes have drawbacks: RO is efficient but uses expensive electrical energy; thermal distillation is inefficient but uses less expensive thermal energy. This work aims to provide an efficient RO plant that uses thermal energy. A steam-Rankine cycle has been designed to drive mechanically a batch-RO system that achieves high recovery, without the high energy penalty typically incurred in a continuous-RO system. The steam may be generated by solar panels, biomass boilers, or as an industrial by-product. A novel mechanical arrangement has been designed for low cost, and a steam-jacketed arrangement has been designed for isothermal expansion and improved thermodynamic efficiency. Based on detailed heat transfer and cost calculations, a gain output ratio of 69-162 is predicted, enabling water to be treated at a cost of 71 Indian Rupees/m3 at small scale. Costs will reduce with scale-up. Plants may be designed for a wide range of outputs, from 5 m3/day, up to commercial versions producing 300 m3/day of clean water from brackish groundwater.

Copyright law as a matter of (inter)national security? – The attempt to securitise commercial infringement and its spill-over onto individual liability

This article evaluates the way in which copyright infringement has been gradually shifting from an area of civil liability to one of criminal penalty. Traditionally, consideration of copyright issues has been undertaken from a predominantly legal and/or economic perspectives. Whereas traditional legal analysis can explain what legal changes are occurring, and what impact these changes may have, they may not effectively explain ‘how’ these changes have come to occur. The authors propose an alternative inter-disciplinary approach, combining legal analysis with critical security studies, which may help to explain in greater detail how policies in this field have developed. In particular, through applied securitisation theory, this article intends to demonstrate the appropriation of this field by a security discourse, and its consequences for societal and legal developments. In order to explore how the securitisation framework may be a valid approach to a subject such as copyright law and to determine the extent to which copyright law may be said to have been securitised, this article will begin by explaining the origins and main features of securitisation theory, and its applicability to legal study. The authors will then attempt to apply this framework to the development of a criminal law approach to copyright infringement, by focusing on the security escalation it has undergone, developing from an economic issue into one of international security. The analysis of this evolution will be mainly characterised by the securitisation moves taking place at national, European and international levels. Finally, a general reflection will be carried out on whether the securitisation of copyright has indeed been successful and on what the consequences of such a success could be.

RIN transfer in 2nd-order distributed amplification with ultralong fiber lasers

We investigate numerically the effect of ultralong Raman laser fiber amplifier design parameters, such as span length, pumping distribution and grating reflectivity, on the RIN transfer from the pump to the transmitted signal. Comparison is provided to the performance of traditional second-order Raman amplified schemes, showing a relative performance penalty for ultralong laser systems that gets smaller as span length increases. We show that careful choice of system parameters can be used to partially offset such penalty. © 2010 Optical Society of America.

Raman fibre laser based amplification in coherent transmission systems

The thesis presents a detailed study of different Raman fibre laser (RFL) based amplification techniques and their applications in long-haul/unrepeatered coherent transmission systems. RFL based amplifications techniques were characterised from different aspects, including signal/noise power distributions, relative intensity noise (RIN), mode structures of induced Raman fibre lasers, and so on. It was found for the first time that RFL based amplification techniques could be divided into three categories in terms of the fibre laser regime, which were Fabry-Perot fibre laser with two FBGs, weak Fabry-Perot fibre laser with one FBG and very low reflection near the input, and random distributed feedback (DFB) fibre laser with one FBG. It was also found that lowering the reflection near the input could mitigate the RIN of the signal significantly, thanks to the reduced efficiency of the Stokes shift from the FW-propagated pump. In order to evaluate the transmission performance, different RFL based amplifiers were evaluated and optimised in long-haul coherent transmission systems. The results showed that Fabry-Perot fibre laser based amplifier with two FBGs gave >4.15 dB Q factor penalty using symmetrical bidirectional pumping, as the RIN of the signal was increased significantly. However, random distributed feedback fibre laser based amplifier with one FBG could mitigate the RIN of the signal, which enabled the use of bidirectional second order pumping and consequently give the best transmission performance up to 7915 km. Furthermore, using random DFB fibre laser based amplifier was proved to be effective to combat the nonlinear impairment, and the maximum reach was enhanced by >28% in mid-link single/dual band optical phase conjugator (OPC) transmission systems. In addition, unrepeatered transmission over >350 km fibre length using RFL based amplification technique were presented experimentally using DP-QPSK and DP-16QAM transmitter.

On the implementation of the L-Nash bargaining solution in two-person bargaining games

The “Nash program” initiated by Nash (Econometrica 21:128–140, 1953) is a research agenda aiming at representing every axiomatically determined cooperative solution to a game as a Nash outcome of a reasonable noncooperative bargaining game. The L-Nash solution first defined by Forgó (Interactive Decisions. Lecture Notes in Economics and Mathematical Systems, vol 229. Springer, Berlin, pp 1–15, 1983) is obtained as the limiting point of the Nash bargaining solution when the disagreement point goes to negative infinity in a fixed direction. In Forgó and Szidarovszky (Eur J Oper Res 147:108–116, 2003), the L-Nash solution was related to the solution of multiciteria decision making and two different axiomatizations of the L-Nash solution were also given in this context. In this paper, finite bounds are established for the penalty of disagreement in certain special two-person bargaining problems, making it possible to apply all the implementation models designed for Nash bargaining problems with a finite disagreement point to obtain the L-Nash solution as well. For another set of problems where this method does not work, a version of Rubinstein’s alternative offer game (Econometrica 50:97–109, 1982) is shown to asymptotically implement the L-Nash solution. If penalty is internalized as a decision variable of one of the players, then a modification of Howard’s game (J Econ Theory 56:142–159, 1992) also implements the L-Nash solution.

A túlképzettség vizsgálata a Debreceni Egyetem végzettjei esetében (The effect of overeducation in the case of graduates of University of Debrecen)

Jelen cikk célja annak mélyrehatóbb vizsgálata, hogy a felsőfokú végzettséggel rendelkező frissdiplomások nagyarányú létszámnövekedése milyen hatással volt a munkaerő-piaci helyzetükre, jelen esetben keresetükre. Homogén-e az egyetemet végzett hallgatók csoportja, vagy elkülöníthetők olyan alcsoportok, amelyben a végzett hallgatók kevesebbet keresnek jobb helyzetben lévő társaiknál? A fentebbi kérdés megválaszolására a Debreceni Egyetem 2007-ben és 2009-ben végzett hallgatóinak Diplomás Pályakövető Rendszeren keresztül nyert adatait használta fel a szerző. A tömegesedés egyik következménye lehet, hogy a felsőfokú végzettséggel rendelkező munkavállaló nem talál a végzettségének megfelelő munkát, és így kénytelen olyan munkakört betölteni, amelynek végzettségigénye alacsonyabb, mint az övé. Az ilyen módon túlképzett munkavállalók keresete alacsonyabb, mint hasonló végzettségű, de megfelelő munkakörben dolgozó társaiké. Ez a vizsgált minta tanúsága szerint a DE végzettjeinek esetében 12-17% körül alakult, ami megfelel a nemzetközi eredményeknek. _________ The main goal of this article to examine the effect of a large increase in the number of university graduates on their labour market position, mainly on their wages. Is the group of graduated students homogenous, or are there any subgroups in which graduates earn less than their counterparts? To answer this question, the author examines the database of the Graduate Students’ Survey which contains data about the students of University of Debrecen who finished their studies in 2007 and 2009. As a result of overeducation, graduates do not find the kind of jobs which require their level of education. These so called overeducated workers earn less than their counterparts. In this case, this wage penalty is between 12%-17%, which is similar to international results.

The role of death qualification in venirepersons' evaluations of aggravating and mitigating circumstances in capital trials

Death qualification is a part of voir dire that is unique to capital trials. Unlike all other litigation, capital jurors must affirm their willingness to impose both legal standards (either life in prison or the death penalty). Jurors who assert they are able to do so are deemed “death-qualified” and are eligible for capital jury service: jurors who assert that they are unable to do so are deemed “excludable” or “scrupled” and are barred from hearing a death penalty case. During the penalty phase in capital trials, death-qualified jurors weigh the aggravators (i.e., arguments for death) against the mitigators (i.e., arguments for life) in order to determine the sentence. If the aggravating circumstances outweigh the mitigating circumstances, then the jury is to recommend death; if the mitigating circumstances outweigh the aggravating circumstances, then the jury is to recommend life. The jury is free to weigh each aggravating and mitigating circumstance in any matter they see fit. Previous research has found that death qualification impacts jurors' receptiveness to aggravating and mitigating circumstances (e.g., Luginbuhl & Middendorf, 1988). However, these studies utilized the now-defunct Witherspoon rule and did not include a case scenario for participants to reference. The purpose of this study was to investigate whether death qualification affects jurors' endorsements of aggravating and mitigating circumstances when Witt, rather than Witherspoon, is the legal standard for death qualification. Four hundred and fifty venirepersons from the 11 th Judicial Circuit in Miami, Florida completed a booklet of stimulus materials that contained the following: two death qualification questions; a case scenario that included a summary of the guilt and penalty phases of a capital case; a 26-item measure that required participants to endorse aggravators, nonstatutory mitigators, and statutory mitigators on a 6-point Likert scale; and standard demographic questions. Results indicated that death-qualified venirepersons, when compared to excludables, were more likely to endorse aggravating circumstances. Excludable participants, when compared to death-qualified venirepersons, were more likely to endorse nonstatutory mitigators. There was no significant difference between death-qualified and excludable venirepersons with respect to their endorsement of 6 out of 7 statutory mitigators. It would appear that the Furman v. Georgia (1972) decision to declare the death penalty unconstitutional is frustrated by the Lockhart v. McCree (1986) affirmation of death qualification. ^

Space time coding for polynomial phase modulated signals

Polynomial phase modulated (PPM) signals have been shown to provide improved error rate performance with respect to conventional modulation formats under additive white Gaussian noise and fading channels in single-input single-output (SISO) communication systems. In this dissertation, systems with two and four transmit antennas using PPM signals were presented. In both cases we employed full-rate space-time block codes in order to take advantage of the multipath channel. For two transmit antennas, we used the orthogonal space-time block code (OSTBC) proposed by Alamouti and performed symbol-wise decoding by estimating the phase coefficients of the PPM signal using three different methods: maximum-likelihood (ML), sub-optimal ML (S-ML) and the high-order ambiguity function (HAF). In the case of four transmit antennas, we used the full-rate quasi-OSTBC (QOSTBC) proposed by Jafarkhani. However, in order to ensure the best error rate performance, PPM signals were selected such as to maximize the QOSTBC’s minimum coding gain distance (CGD). Since this method does not always provide a unique solution, an additional criterion known as maximum channel interference coefficient (CIC) was proposed. Through Monte Carlo simulations it was shown that by using QOSTBCs along with the properly selected PPM constellations based on the CGD and CIC criteria, full diversity in flat fading channels and thus, low BER at high signal-to-noise ratios (SNR) can be ensured. Lastly, the performance of symbol-wise decoding for QOSTBCs was evaluated. In this case a quasi zero-forcing method was used to decouple the received signal and it was shown that although this technique reduces the decoding complexity of the system, there is a penalty to be paid in terms of error rate performance at high SNRs.

Branch and price solution approach for order acceptance and capacity planning in make -to -order operations

The increasing emphasis on mass customization, shortened product lifecycles, synchronized supply chains, when coupled with advances in information system, is driving most firms towards make-to-order (MTO) operations. Increasing global competition, lower profit margins, and higher customer expectations force the MTO firms to plan its capacity by managing the effective demand. The goal of this research was to maximize the operational profits of a make-to-order operation by selectively accepting incoming customer orders and simultaneously allocating capacity for them at the sales stage. ^ For integrating the two decisions, a Mixed-Integer Linear Program (MILP) was formulated which can aid an operations manager in an MTO environment to select a set of potential customer orders such that all the selected orders are fulfilled by their deadline. The proposed model combines order acceptance/rejection decision with detailed scheduling. Experiments with the formulation indicate that for larger problem sizes, the computational time required to determine an optimal solution is prohibitive. This formulation inherits a block diagonal structure, and can be decomposed into one or more sub-problems (i.e. one sub-problem for each customer order) and a master problem by applying Dantzig-Wolfe’s decomposition principles. To efficiently solve the original MILP, an exact Branch-and-Price algorithm was successfully developed. Various approximation algorithms were developed to further improve the runtime. Experiments conducted unequivocally show the efficiency of these algorithms compared to a commercial optimization solver.^ The existing literature addresses the static order acceptance problem for a single machine environment having regular capacity with an objective to maximize profits and a penalty for tardiness. This dissertation has solved the order acceptance and capacity planning problem for a job shop environment with multiple resources. Both regular and overtime resources is considered. ^ The Branch-and-Price algorithms developed in this dissertation are faster and can be incorporated in a decision support system which can be used on a daily basis to help make intelligent decisions in a MTO operation.^