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

Relaxation oscillations and canards in the Jirsa–Kelso excitator model: global flow perspective

This is the author accepted manuscript. The final version is available from Springer via the DOI in this record.Fenichel’s geometric singular perturbation theory and the blowup method have been very successful in describing and explaining global non-linear phenomena in systems with multiple time-scales, such as relaxation oscillations and canards. Recently, the blowup method has been extended to systems with flat, unbounded slow manifolds that lose normal hyperbolicity at infinity. Here, we show that transition between discrete and periodic movement captured by the Jirsa-Kelso excitator is a new example of such phenomena. We, first, derive equations of the Jirsa-Kelso excitator with explicit time scale separation and demonstrate existence of canards in the systems. Then, we combine the slow-fast analysis, blowup method and projection onto the the Poincar´e sphere to understand the return mechanism of the periodic orbits in the singular case, € = 0.KT-A gratefully acknowledges the financial support of the EPSRC via grant EP/N014391/1. This work was supported by The Higher Committee For Education Development in Iraq (HCED) and the University of Mosul

Covid-19 and the Role of Intellectual Property - Position Statement of the Max Planck Institute for Innovation and Competition of 7 May 2021

In this Statement, the authors take a position on the waiver of intellectual property (IP) protection currently being considered by the members of the World Trade Organisation. The waiver was initiated by India and South Africa as a measure to enable rapid access to affordable medical products that are necessary to combat Covid-19. The initiative gained momentum after the US decided to support it. The authors do not consider this path to be expedient. The Statement presents factual and legal arguments why a comprehensive waiver of IP protection is unlikely to be a necessary and suitable measure towards the pursued objective. Overall, it argues that IP rights may so far have played an enabling and facilitating rather than hindering role in overcoming Covid-19. The global community might not be better off if IP rights are waived, neither during nor after the pandemic. There are more efficient and direct ways to supply developing countries with vaccines quickly – if the industrialised countries are willing to do their share

Neurologically motivated coupling functions in models of motor coordination

This is the final version. Available from the Society for Industrial and Applied Mathematics via the DOI in this recordWe present an analysis of two Haken–Kelso–Bunz (HKB) oscillators coupled by a neurologically motivated function. We study the effect of time delay and weighted self-feedback and mutual feedback on the synchronization behavior of the model. We focus on identifying parameter regimes supporting experimentally observed decrease in oscillation amplitude and loss of anti-phase stability that has inspired the development of the HKB model. We show that a combination of cross-talk and nonlinearity in the coupling, along with physiologically relevant time delay, is able to quantitatively account for both drop in oscillation amplitude and loss of anti-phase stability in a frequency dependent manner. Furthermore, we demonstrate that the transition between discrete and rhythmic movements could be captured by this model. To this end, we carry out theoretical and numerical analysis of the emergence of in-phase and anti-phase oscillations.Engineering and Physical Science Research Council (EPSRC

Proper and improper uses of MCDA methods in energy systems analysis

Global Challenges (FGGA

Robust spike timing in an excitable cell with delayed feedback

This is the author accepted manuscript. The final version is available from the Royal Society via the DOI in this recordData and materials availability: Data and computer code related to the mathematical model and dynamic clamp experiments can be downloaded from the GitHub repository https://github.com/SlowinskiPiotr/MorrisLecarDDEThe initiation and regeneration of pulsatile activity is a ubiquitous feature observed in excitable systems with delayed feedback. Here, we demonstrate this phenomenon in a real biological cell. We establish a critical role of the delay resulting from the finite propagation speed of electrical impulses on the emergence of persistent multiple-spike patterns. We predict the co-existence of a number of such patterns in a mathematical model and use a biological cell subject to dynamic clamp to confirm our predictions in a living mammalian system. Given the general nature of our mathematical model and experimental system, we believe that our results capture key hallmarks of physiological excitability that are fundamental to information processing.Medical Research Council (MRC)Wellcome TrustEngineering and Physical Sciences Research Council (EPSRC)Technical University of Munich – Institute for Advanced StudyRoyal Societ

New insights into lake responses to rapid climate change : the Younger Dryas in Lake Goscia(z) over dot, central Poland

The sediment profile from Lake Goscia(z) over dot in central Poland comprises a continuous, seasonally resolved and exceptionally well-preserved archive of the Younger Dryas (YD) climate variation. This provides a unique opportunity for detailed investigation of lake system responses during periods of rapid climate cooling (YD onset) and warming (YD termination). The new varve record of Lake Goscia(z) over dot presented here spans 1662 years from the late Allerod (AL) to the early Preboreal (PB). Microscopic varve counting provides an independent chronology with a YD duration of 1149+14/-22 years, which confirms previous results of 1140 +/- 40 years. We link stable oxygen isotopes and chironomid-based air temperature reconstructions with the response of various geochemical and varve microfacies proxies especially focusing on the onset and termination of the YD. Cooling at the YD onset lasted similar to 180 years, which is about a century longer than the terminal warming that was completed in similar to 70 years. During the AL/YD transition, environmental proxy data lagged the onset of cooling by similar to 90 years and revealed an increase of lake productivity and internal lake re-suspension as well as slightly higher detrital sediment input. In contrast, rapid warming and environmental changes during the YD/PB transition occurred simultaneously. However, initial changes such as declining diatom deposition and detrital input occurred already a few centuries before the rapid warming at the YD/PB transition. These environmental changes likely reflect a gradual increase in summer air temperatures already during the YD. Our data indicate complex and differing environmental responses to the major climate changes related to the YD, which involve different proxy sensitivities and threshold processes.Peer reviewe