Flight Gate Assignment with a Quantum Annealer

Optimal flight gate assignment is a highly relevant optimization problem from airport management. Among others, an important goal is the minimization of the total transit time of the passengers. The corresponding objective function is quadratic in the binary decision variables encoding the flight-to-gate assignment. Hence, it is a quadratic assignment problem being hard to solve in general. In this work we investigate the solvability of this problem with a D-Wave quantum annealer. These machines are optimizers for quadratic unconstrained optimization problems (QUBO). Therefore the flight gate assignment problem seems to be well suited for these machines. We use real world data from a mid-sized German airport as well as simulation based data to extract typical instances small enough to be amenable to the D-Wave machine. In order to mitigate precision problems, we employ bin packing on the passenger numbers to reduce the precision requirements of the extracted instances. We find that, for the instances we investigated, the bin packing has little effect on the solution quality. Hence, we were able to solve small problem instances extracted from real data with the D-Wave 2000Q quantum annealer.Comment: Updated figure

Lingulodinium machaerophorum expansion over the last centuries in the Caspian Sea reflects global warming

This article is made available through the Brunel Open Access Publishing Fund. Copyright @ Author(s) 2012. This work is distributed under the Creative Commons Attribution 3.0 License.We analysed dinoflagellate cyst assemblages in four short sediment cores, two of them dated by radionuclides, taken in the south basin of the Caspian Sea. The interpretation of the four sequences is supported by a collection of 27 lagoonal or marine surface sediment samples. A sharp increase in the biomass of the dinocyst occurs after 1967, especially owing to Lingulodinium machaerophorum. Considering nine other cores covering parts or the whole of Holocene, this species started to develop in the Caspian Sea only during the last three millennia. By analysing instrumental data and collating existing reconstructions of sea level changes over the last few millennia, we show that the main forcing of the increase of L. machaerophorum percentages and of the recent dinocyst abundance is global climate change, especially sea surface temperature increase. Sea level fluctuations likely have a minor impact. We argue that the Caspian Sea has entered the Anthropocene

Brane-f(R)f(R) gravity and dark matter

The collision-free Boltzmann equation is used in the context of brane-$f(R)$ gravity to derive the virial theorem. It is shown that the virial mass is proportional to certain geometrical terms appearing in the Einstein field equations and contributes to gravitational energy and that such a geometric mass can be attributed to the virial mass discrepancy in a cluster of galaxies. In addition, the galaxy rotation curves are studied by utilizing the concept of conformal symmetry and notion of conformal Killing symmetry. The field equations may then be obtained in an exact parametric form in terms of the parameter representing the conformal factor. This provides the possibility of studying the behavior of the angular velocity of a test particle moving in a stable circular orbit. The tangential velocity can be derived as a function of the conformal factor and integration constants, resulting in a constant value at large radial distances. Relevant phenomenon such as the deflection of light passing through a region where the rotation curves are flat and the radar echo delay are also studied.Comment: 12 pages, 2 figures, to appear in PR

Optimal and Long-Term Dynamic Transport Policy Design: Seeking Maximum Social Welfare through a Pricing Scheme.

This article presents an alternative approach to the decision-making process in transport strategy design. The study explores the possibility of integrating forecasting, assessment and optimization procedures in support of a decision-making process designed to reach the best achievable scenario through mobility policies. Long-term evaluation, as required by a dynamic system such as a city, is provided by a strategic Land-Use and Transport Interaction (LUTI) model. The social welfare achieved by implementing mobility LUTI model policies is measured through a cost-benefit analysis and maximized through an optimization process throughout the evaluation period. The method is tested by optimizing a pricing policy scheme in Madrid on a cordon toll in a context requiring system efficiency, social equity and environmental quality. The optimized scheme yields an appreciable increase in social surplus through a relatively low rate compared to other similar pricing toll schemes. The results highlight the different considerations regarding mobility impacts on the case study area, as well as the major contributors to social welfare surplus. This leads the authors to reconsider the cost-analysis approach, as defined in the study, as the best option for formulating sustainability measures

q-Form fields on p-branes

In this paper, we give one general method for localizing any form (q-form) field on p-branes with one extra dimension, and apply it to some typical p-brane models. It is found that, for the thin and thick Minkowski branes with an infinite extra dimension, the zero mode of the q-form fields with q<(p-1)/2 can be localized on the branes. For the thick Minkowski p-branes with one finite extra dimension, the localizable q-form fields are those with q<p/2, and there are also some massive bound Kaluza-Klein modes for these q-form fields on the branes. For the same q-form field, the number of the bound Kaluza-Klein modes (but except the scalar field (q=0)) increases with the dimension of the p-branes. Moreover, on the same p-brane, the q-form fields with higher q have less number of massive bound KK modes. While for a family of pure geometrical thick p-branes with a compact extra dimension, the q-form fields with q<p/2 always have a localized zero mode. For a special pure geometrical thick p-brane, there also exist some massive bound KK modes of the q-form fields with q<p/2, whose number increases with the dimension of the p-brane.Comment: 14 pages, 2 figures, published versio

Trends of research productivity across author gender and research fields: A multidisciplinary and multi-country observational study

Bibliographic properties of more than 75 million scholarly articles, are examined and trends in overall research productivity are analysed as a function of research field (over the period of 1970-2020) and author gender (over the period of 2006-2020). Potential disruptive effects of the Covid-19 pandemic are also investigated. Over the last decade (2010-2020), the annual number of publications have invariably increased every year with the largest relative increase in a single year happening in 2019 (more than 6% relative growth). But this momentum was interrupted in 2020. Trends show that Environmental Sciences and Engineering Environmental have been the fastest growing research fields. The disruption in patterns of scholarly publication due to the Covid-19 pandemic was unevenly distributed across fields, with Computer Science, Engineering and Social Science enduring the most notable declines. The overall trends of male and female productivity indicate that, in terms of absolute number of publications, the gender gap does not seem to be closing in any country. The trends in absolute gap between male and female authors is either parallel (e.g., Canada, Australia, England, USA) or widening (e.g., majority of countries, particularly Middle Eastern countries). In terms of the ratio of female to male productivity, however, the gap is narrowing almost invariably, though at markedly different rates across countries. While some countries are nearing a ratio of .7 and are well on track for a 0.9 female to male productivity ratio, our estimates show that certain countries (particularly across the Middle East) will not reach such targets within the next 100 years. Without interventional policies, a significant gap will continue to exist in such countries. The decrease or increase in research productivity during the first year of the pandemic, in contrast to trends established before 2020, was generally parallel for male and female authors. There has been no substantial gender difference in the disruption due to the pandemic. However, opposite trends were found in a few cases. It was observed that, in some countries (e.g., The Netherlands, The United States and Germany), male productivity has been more negatively affected by the pandemic. Overall, female research productivity seems to have been more resilient to the disruptive effect of Covid-19 pandemic, although the momentum of female researchers has been negatively affected in a comparable manner to that of males

Forced vibration analysis of laminated composite plates under the action of a moving vehicle

This paper provides a finite element analysis of laminated composite plates under the action of a moving vehicle. The vehicle is modeled as a rigid body with four suspension systems, each consisting of a springdashpot. Overall, the vehicle possesses three degrees of freedom: vertical, rolling, and pitching motions. The equations of motion of the plate are deduced based on first-order shear deformation theory. Using the EulerLagrange equations, the system of coupled equations of motion is extracted and solved by using the Newmark time discretization scheme. The algorithm is validated through the comparison of both the free and forced vibration results provided by the present model and exact or numerical results reported in the literature. The effects are investigated of several system parameters on the dynamic response

A discrete firefly algorithm to solve a rich vehicle routing problem modelling a newspaper distribution system with recycling policy

A real-world newspaper distribution problem with recycling policy is tackled in this work. In order to meet all the complex restrictions contained in such a problem, it has been modeled as a rich vehicle routing problem, which can be more specifically considered as an asymmetric and clustered vehicle routing problem with simultaneous pickup and deliveries, variable costs and forbidden paths (AC-VRP-SPDVCFP). This is the first study of such a problem in the literature. For this reason, a benchmark composed by 15 instances has been also proposed. In the design of this benchmark, real geographical positions have been used, located in the province of Bizkaia, Spain. For the proper treatment of this AC-VRP-SPDVCFP, a discrete firefly algorithm (DFA) has been developed. This application is the first application of the firefly algorithm to any rich vehicle routing problem. To prove that the proposed DFA is a promising technique, its performance has been compared with two other well-known techniques: an evolutionary algorithm and an evolutionary simulated annealing. Our results have shown that the DFA has outperformed these two classic meta-heuristics

Effect of alveolar ridge preservation with PDFDBA on orthodontic tooth movement rate, formation of gingival invagination and root resorption: A randomized, controlled pilot study

Tooth extraction results in resorptive remodeling of the alveolar bone, but alveolar ridge preservation procedure maintains the original shape of the extraction socket. This may be beneficial for space closure by orthodontic tooth movement (OTM). In the current pilot study for randomized controlled clinical trial the effect of alveolar ridge preservation with partial demineralized freezedried bone allograft (PDFDBA) on OTM rate, formation of gingival invagination and root resorption was evaluated. Both mandibular first premolars of 6 patients were extracted due to orthodontic treatment. In a split-mouth study design, alveolar ridge preservation was performed on one side, while the other side served as a control and the extraction socket healed naturally. After 6 weeks of healing period, the canines were moved to the extraction site to close the extraction space. Eight weeks later, the amount of OTM was measured. After space closure, the extraction sites were examined for the presence of gingival invagination. Root resorption was evaluated on digital panoramic radiographs. Photographs were taken for documentation. There was no significant difference in OTM rate between the ridge preserved areas and naturally healed sockets. Gingival invagination formed in 5 of 6 naturally healed sockets; none of the ridge preserved areas showed formation of gingival invagination. No root resorption was observed in any of the teeth adjacent to the extraction sites. Alveolar ridge preservation with PDFDBA has no effect on the rate of OTM and root resorption but prevents formation of gingival invagination during orthodontic space closure

Effect of Protic and Aprotic Formamide-Based Organic Electrolytes for Rechargeable Zinc/MnO2 Battery

Data Availability Statement: The data that support the findings of this study are openly available in Brunel Figshare at https://doi.org/10.17633/rd.brunel.25093388.v1.Zinc ion batteries (ZIBs) are emerging as a promising and cost-effective alternative energy storage system compared to other metal-ion batteries. Aqueous electrolytes have been extensively studied in Zn-ion batteries which has shown issues related to cathode dissolution. In comparison, little has been looked into the use of organic electrolytes in ZIBs. Here, we have studied both protic and aprotic forms of formamide-based organic electrolytes containing Zn trifluoromethanesulfonate and their influence on the Zn solvation chemistry, electrochemistry, and performance of Zn-MnO2 battery. It was observed that protic-based electrolytes gave a much better capacity and stability for the Zn-MnO2 battery. A capacity close to 150 mAh g−1 was obtained with formamide electrolyte at a current density of 0.25 A g−1. For all the other formamide-based electrolytes tested, the capacity was lower. After 100 cycles, an average capacity retention of 72 % was obtained for formamide-based electrolyte. This study shows that protic-based electrolytes might be a suitable option for non-aqueous-based Zn-ion batteries.This research was funded, in whole by EPSRC. Grant Number: EP/W015129/