A Common Basis for Agent Organisation in BDI Languages

Programming languages based on the BDI style of agent model are now common. Within these there appears to be some, limited, agreement on the core functionality of agents. However, when we come to multi-agent organisations, not only do many BDI languages have no specific organisational structures, but those that do exist are very diverse. In this paper, we aim to provide a unifying framework for the core aspects of agent organisation, covering groups, teams and roles, as well as organisations. Thus, we describe a simple organisational mechanism, and show how several well known approaches can be embedded within it. Although the mechanism we use is derived from the MetateM programming language, we do not assume any specific BDI language. The organisational mechanism is intended to be independent of the underlying agent language and so we aim to provide a common core for future developments in agent organisation.

IMPLICAÇÕES SIMBÓLICAS NA ORGANIZAÇÃO DE UM HOME CARE: INTERPRETAÇÕES ENTRE A EQUIPE DE SAÚDE E OS CUIDADORES FAMILIARES

RESUMO O objetivo deste artigo é compreender as implicações simbólicas na organização de um home care em torno das práticas dos cuidadores familiares e da equipe de saúde. Utiliza-se uma perspectiva simbólica para desvendar símbolos resultantes de interações sociais presentes no dia-a-dia do grupo estudado, de forma a possibilitar a compreensão de seus significados. A pesquisa empírica realizada foi de cunho qualitativo e descritivo. Os dados foram coletados por meio de sete entrevistas semiestruturadas com os cuidadores familiares dos pacientes e três grupos focais com 27 profissionais do home care de uma empresa de saúde privada. Após a transcrição das entrevistas e dos grupos focais, os dados obtidos foram agrupados e categorizados por meio da análise de conteúdo de modelo misto. Os resultados indicam que interpretações de aspectos simbólicos interferem na avaliação e operação do atendimento domiciliar em oposição ao hospitalar. Elas levam à reconstrução social dos simbolismos dos familiares, porque se inserem em um novo contexto adverso (a doença), a despeito de permanecerem em um contexto conhecido (o lar). Nessa reconstrução, as práticas dos atores organizacionais envolvidos se legitimam ou são rejeitadas; portanto, cabe reconhecer tal dinâmica na preparação das equipes de profissionais para atuarem no serviço de home care

Enhanced performance in fusion plasmas through turbulence suppression by megaelectronvolt ions

© 2022, The Author(s), under exclusive licence to Springer Nature Limited.Alpha particles with energies on the order of megaelectronvolts will be the main source of plasma heating in future magnetic confinement fusion reactors. Instead of heating fuel ions, most of the energy of alpha particles is transferred to electrons in the plasma. Furthermore, alpha particles can also excite Alfvénic instabilities, which were previously considered to be detrimental to the performance of the fusion device. Here we report improved thermal ion confinement in the presence of megaelectronvolts ions and strong fast ion-driven Alfvénic instabilities in recent experiments on the Joint European Torus. Detailed transport analysis of these experiments reveals turbulence suppression through a complex multi-scale mechanism that generates large-scale zonal flows. This holds promise for more economical operation of fusion reactors with dominant alpha particle heating and ultimately cheaper fusion electricity.N

Real-time-capable prediction of temperature and density profiles in a tokamak using RAPTOR and a first-principle-based transport model

The RAPTOR code is a control-oriented core plasma profile simulator with various applications in control design and verification, discharge optimization and real-time plasma simulation. To date, RAPTOR was capable of simulating the evolution of poloidal flux and electron temperature using empirical transport models, and required the user to input assumptions on the other profiles and plasma parameters. We present an extension of the code to simulate the temperature evolution of both ions and electrons, as well as the particle density transport. A proof-of-principle neural-network emulation of the quasilinear gyrokinetic QuaLiKiz transport model is coupled to RAPTOR for the calculation of first-principle-based heat and particle turbulent transport. These extended capabilities are demonstrated in a simulation of a JET discharge. The multi-channel simulation requires ∼0.2 s to simulate 1 second of a JET plasma, corresponding to ∼20 energy confinement times, while predicting experimental profiles within the limits of the transport model. The transport model requires no external inputs except for the boundary condition at the top of the H-mode pedestal. This marks the first time that simultaneous, accurate predictions of Te, Tiand nehave been obtained using a first-principle-based transport code that can run in faster-than-real-time for present-day tokamaks

Runaway electron beam control

Post-disruption runaway electron (RE) beams in tokamaks with large current can cause deep melting of the vessel and are one of the major concerns for ITER operations. Consequently, a considerable effort is provided by the scientific community in order to test RE mitigation strategies. We present an overview of the results obtained at FTU and TCV controlling the current and position of RE beams to improve safety and repeatability of mitigation studies such as massive gas (MGI) and shattered pellet injections (SPI). We show that the proposed RE beam controller (REB-C) implemented at FTU and TCV is effective and that current reduction of the beam can be performed via the central solenoid reducing the energy of REs, providing an alternative/parallel mitigation strategy to MGI/SPI. Experimental results show that, meanwhile deuterium pellets injected on a fully formed RE beam are ablated but do not improve RE energy dissipation rate, heavy metals injected by a laser blow off system on low-density flat-top discharges with a high level of RE seeding seem to induce disruptions expelling REs. Instabilities during the RE beam plateau phase have shown to enhance losses of REs, expelled from the beam core. Then, with the aim of triggering instabilities to increase RE losses, an oscillating loop voltage has been tested on RE beam plateau phase at TCV revealing, for the first time, what seems to be a full conversion from runaway to ohmic current. We finally report progresses in the design of control strategies at JET in view of the incoming SPI mitigation experiments

Comparison of runaway electron generation parameters in small, medium-sized and large tokamaks - A survey of experiments in COMPASS, TCV, ASDEX-Upgrade and JET

This paper presents a survey of the experiments on runaway electrons (RE) carried out recently in frames of EUROFusion Consortium in different tokamaks: COMPASS, ASDEX-Upgrade, TCV and JET. Massive gas injection (MGI) has been used in different scenarios for RE generation in small and medium-sized tokamaks to elaborate the most efficient and reliable ones for future RE experiments. New data on RE generated at disruptions in COMPASS and ASDEX-Upgrade was collected and added to the JET database. Different accessible parameters of disruptions, such as current quench rate, conversion rate of plasma current into runaways, etc have been analysed for each tokamak and compared to JET data. It was shown, that tokamaks with larger geometrical sizes provide the wider limits for spatial and temporal variation of plasma parameters during disruptions, thus extending the parameter space for RE generation. The second part of experiments was dedicated to study of RE generation in stationary discharges in COMPASS, TCV and JET. Injection of Ne/Ar have been used to mock-up the JET MGI runaway suppression experiments. Secondary RE avalanching was identified and quantified for the first time in the TCV tokamak in RE generating discharges after massive Ne injection. Simulations of the primary RE generation and secondary avalanching dynamics in stationary discharges has demonstrated that RE current fraction created via avalanching could achieve up to 70-75% of the total plasma current in TCV. Relaxations which are reminiscent the phenomena associated to the kinetic instability driven by RE have been detected in RE discharges in TCV. Macroscopic parameters of RE dominating discharges in TCV before and after onset of the instability fit well to the empirical instability criterion, which was established in the early tokamaks and examined by results of recent numerical simulations