270 research outputs found
Asset Price Dynamics in a Financial Market with Heterogeneous Trading Strategies and Time Delays
In this paper we present a continuous time dynamical model of heterogeneous
agents interacting in a financial market where transactions are cleared by a
market maker. The market is composed of fundamentalist, trend following and
contrarian agents who process information from the market with different time
delays. Each class of investor is characterized by path dependent risk
aversion. We also allow for the possibility of evolutionary switching between
trend following and contrarian strategies. We find that the system shows
periodic, quasi-periodic and chaotic dynamics as well as synchronization
between technical traders. Furthermore, the model is able to generate time
series of returns that exhibit statistical properties similar to those of the
S&P500 index, which is characterized by excess kurtosis, volatility clustering
and long memoryComment: 14 pages, 5 figure
Asset Price Dynamics in a Financial Market with Heterogeneous Trading Strategies and Time Delays
In this paper we present a continuous time dynamical model of heterogeneous agents interacting in a financial market where transactions are cleared by a market maker. The market is composed of fundamentalist, trend following and contrarian agents who process information from the market with different time delays. Each class of investors is characterized by path dependent risk aversion. We also allow for the possibility of evolutionary switching between trend following and contrarian strategies. We find that the system shows periodic, quasi-periodic and chaotic dynamics as well as synchronization between technical traders. Furthermore, the model is able to generate time series of returns that exhibit statistical properties similar to those of the S&P500 index, which is characterized by excess kurtosis, volatility clustering and long memory.Dynamic asset pricing; Heterogeneous agents; Complex dynamics; Strange attractors; Chaos; Intermittency; Stock market dynamics; Synchronization
Organic Fertilization In A âTomato â Peaâ Rotation In Southern Italy
The use of alternative to mineral fertilizers is an important issue in organic systems. A four-year field experiment to evaluate the effects of organic fertilizers on yield and quality of processing tomato and proteic pea in rotation, was carried out in Southern Italy. The fertilization treatments aimed to supply 100 kg ha-1 of N for tomato and 60 kg ha-1 of P2O5 for pea and were: 1) an organic biological fertilizer (BIO); 2) an experimental compost obtained by olive residues, sludge and straw mixture (COMP); 3) a control managed with traditional chemical fertilizers (ammonium nitrate and perphosphate, MIN). At harvest, the main productive and qualitative parameters were assessed.
Tomato fruit yield did not differ among the fertilization treatments, but unripe fruit yield was higher in the MIN and BIO treatment; MIN showed also smaller fruit than BIO and COMP. The N availability during crop cycle influenced the mean fruit weight and maturity date. No difference among treatments was observed for pea in rotation with tomato and, similarly, on the wheat cropped without fertilization following the two crops.
The possibility to use organic fertilizer for processing tomato and proteic pea has been evaluated and the conclusion is that organic fertilization is comparable to mineral one from a productive and qualitative point of view
P-wave and surface wave survey for permafrost analysis in alpine regions
We discuss the results of seismic survey to delineate temporal and spatial changes of frozen layer in Alpine environments. The seismic characterization allows us to detect changes of soil deformability properties related to the temperature effect on subsoi
Wearable Intrinsically Soft, Stretchable, Flexible Devices for Memories and Computing
A recent trend in the development of high mass consumption electron devices is towards electronic textiles (e-textiles), smart wearable devices, smart clothes, and flexible or printable electronics. Intrinsically soft, stretchable, flexible, Wearable Memories and Computing devices (WMCs) bring us closer to sci-fi scenarios, where future electronic systems are totally integrated in our everyday outfits and help us in achieving a higher comfort level, interacting for us with other digital devices such as smartphones and domotics, or with analog devices, such as our brain/peripheral nervous system. WMC will enable each of us to contribute to open and big data systems as individual nodes, providing real-time information about physical and environmental parameters (including air pollution monitoring, sound and light pollution, chemical or radioactive fallout alert, network availability, and so on). Furthermore, WMC could be directly connected to human brain and enable extremely fast operation and unprecedented interface complexity, directly mapping the continuous states available to biological systems. This review focuses on recent advances in nanotechnology and materials science and pays particular attention to any result and promising technology to enable intrinsically soft, stretchable, flexible WMC
Arbeitsbelastung bei Berufsschullehrpersonen im Kanton ZĂŒrich vor und wĂ€hrend der Covid-19-Pandemie
Die Berufsfachschulen und insbesondere die Berufsschullehrpersonen leisten einen wichtigen Beitrag zur Entwicklung der Gesellschaft. LeistungsfĂ€hige und gesunde Berufsschullehrpersonen sind hierzu unabdingbar. Vor diesem Hintergrund fragt sich, welchen Einfluss die Covid-19-Pandemie und die damit einhergehende VerĂ€nderung der Arbeitsbedingungen auf das Wohlbefinden der Berufsschullehrpersonen haben. Konkret liefert die vorliegende Arbeit einen Einblick in die Wahrnehmung der Arbeitsbelastung von Berufsschullehrpersonen vor und wĂ€hrend der Covid-19-Pandemie im Kanton ZĂŒrich.
Zu deren Ermittlung befragte der Autor mittels Online-Umfrage Berufsschullehrpersonen
im Kanton ZĂŒrich, wobei deren 107 teilnahmen. Bei der statistischen Auswertung wurden neben der allgemeinen Arbeitsbelastung verschiedene Belastungsfaktoren berĂŒcksichtigt. Schliesslich flossen demografische Merkmale und verschiedene Ressourcen der Berufsschullehrpersonen ein.
ZunĂ€chst lĂ€sst sich festhalten, dass die allgemeine Arbeitsbelastung der Berufsschullehrpersonen wĂ€hrend der Covid-19-Pandemie in hoch signifikantem Umfang zunahm. Die grösste Belastung geht auf die beiden zusĂ€tzlich fĂŒr den Zeitraum wĂ€hrend der Covid-19-Pandemie erhobenen Belastungsfaktoren «Maskenpflicht im Unterricht» und «Ungewissheit ĂŒber die Dauer der Corona-Massnahmen und deren Auswirkungen auf den Schulbetrieb» zurĂŒck. Mit Bezug auf die demografischen Merkmale fĂ€llt auf, dass gewisse Merkmale einen Einfluss auf die Belastungswahrnehmung zeigen, wĂ€hrend andere keinen Unterschied aufweisen. Letzteres trifft bspw. auf das Geschlecht der Berufsschullehrpersonen zu. DemgegenĂŒber kann zumindest in Bezug auf die Zeit wĂ€hrend der Covid-19-Pandemie eine signifikant höhere Belastungswahrnehmung bei Lehrpersonen mit einem höheren Arbeitspensum ausgemacht werden. Weiter tritt zu Tage, dass je nach Menge vorhandener Ressourcen die Arbeitsbelastung anders wahrgenommen wird. WĂ€hrend der Covid-19-Pandemie sind diese Unterschiede signifikant. Schliesslich geht aus den erhobenen Ergebnissen hervor, dass fĂŒr beide ZeitrĂ€ume die ZusammenhĂ€nge zwischen den Ressourcen und der allgemeinen Arbeitsbelastung durchwegs negativ ausfallen.
Aus den gewonnenen Erkenntnissen ergeben sich Hinweise, dass die Covid-19- Pandemie Auswirkungen auf die empfundene Arbeitsbelastung von Berufsschullehrpersonen hat. Dies hĂ€ngt mutmasslich mit den von heute auf morgen verĂ€nderten Rahmenbedingungen zusammen. Die Arbeit vermag daher Anhaltspunkte zu liefern, wie sich VerĂ€nderungen an Schulen sowie im Schulsystem auf die Wahrnehmung der Arbeitsbelastung auswirken können. Zu berĂŒcksichtigen ist jedoch, dass die Umfrage aufgrund des Stichprobencharakters nicht reprĂ€sentativ ist. Ăberdies bringt jede VerĂ€nderung spezifische Herausforderungen und Probleme mit sich, weshalb sich die Resultate zur Covid-19-Pandemie nur beschrĂ€nkt auf andere Neuerungen ĂŒbertragen lassen
MultiphysicsâEnabled Liquid State Thermal Harvesting: Synergistic Effects between Pyroelectricity and Triboelectrification
Energy consumption levels show a never-ending increase since the industrial era. Toward sustainability objectives, it is of outstanding importance to reduce the amount of wasted energy, that typically comes as waste heat, as a consequence of nonunitary efficiency of any thermodynamic process. Herein, a breakthrough in conversion of low enthalpy heat into electricity is presented, based on a liquid state device that operates through multiphysics effects: thermomagnetic advection, triboelectricity, pyroelectricity, and LudwigâSorĂ©t effect. A synergistic interaction between ferroelectric surfaces and a complex composition colloidal suspension is evidenced, owing to an enhancement of the generated potential of 365% in comparison with pyroelectric effect and 267% in comparison with triboelectric effect, while the current extracted is 54% higher than the pyroelectric effect only and the power extracted by induction remains substantially unperturbed. The impact of this technology on society is also analyzed, on the basis of a set of practical applications, by means of a computational analysis
Momentum Dumping for Space Robots
During the robotic capture of a target object on orbit, accidental contacts may happen. During contacts, momentum is transferred to the system, causing a drift of the space robot in the inertial space. When no remediation is taken, the arm might converge to singularity or workspace
limit within seconds, compromising the capture operation. This article presents a method to control the end-effector while simultaneously extracting any accumulated momentum in the system to cancel the drift. A feature of the method is that external actuators are only used for the momentum extraction and not to counterbalance the manipulator control forces. The control is validated with experiments using a Hardware-In-the-
Loop (HIL) robotic simulator composed of a 7DOF (Degrees
Of Freedom) arm mounted on a 6DOF moving base
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