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- Lundström, Christina, et al.
(författare)
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Some considerations about the development and implementation process of a new agricultural decision support system for site-specific fertilization
- 2015
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Ingår i: Precision agriculture ’15. - Wageningen : Wageningen Academic Publishers. - 9789086862672 - 9789086868148 ; , s. 437-444
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Konferensbidrag (refereegranskat)abstract
- Precision agriculture provides important routes toward a more sustainable agriculture. Many farmers have the necessary technology to operate site-specifically, but they do not use it in practice, and available IT systems are not used to their full potential. This paper discusses how to reduce the so-called ‘implementation problem’ in order to improve the ongoing development process of a webbased fertilization project in Sweden. The intention of the project is to apply a participatory design approach, and some pitfalls on starting to use this approach in the development and implementation process are identified as well as some suggestions on how to reduce them.
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- Lundström, Christina, et al.
(författare)
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Sustainability as a governing principle in the use of agricultural decision support systems : The case of CropSAT
- 2016
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Ingår i: Social and Technological Transformationof Farming Systems. - Harper Adams University, UK : IFSA consortium. ; , s. 1648-1660, s. 93-94
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Konferensbidrag (refereegranskat)abstract
- Precision agriculture (PA) is an important part of sustainable intensification, where information and communications technology (ICT) and other technologies are necessary but not sufficient for sustainable farming systems. Many agricultural decision support systems (AgriDSS) have been developed to support farmers to manage an increased amount of gathered data. However, the traditional approach to AgriDSS development is based on the knowledge transfer perspective, which has resulted in technology being considered as an isolated phenomenon and thus not adapted to farmers’ actual needs or their decision making in practice. The aim of this study was to improve understanding of farmers’ use of AgriDSS. The theoretical framework of distributed cognition (DCog) was used as a lense when investigating and analysing farmers' use of a software tool developed for calculation of variable rate application (VRA) files for nitrogen (N) fertilisation from satellite images called CropSAT. In a case study, the unit of analysis was broadened to the whole socio-technical system of farmer’s decision-making, including other people and different kinds of tools and artefacts. The results reveal that CropSAT functions as a tool to support decision making and promotes social learning through the use of enhanced professional vision.
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- Nguyen, Hugo, et al.
(författare)
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Micropropulsion systems research and manufacture in Sweden
- 2003
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Ingår i: Proceedings of the 4th Round Table on Micro/Nano Technology for Space, ESTEC, Noordwijk, The Netherlands. - : ESTEC/ESA. ; , s. 476-485
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Konferensbidrag (refereegranskat)abstract
- Micropropulsion for spacecraft is an enabling technology for many future missions, and may increase the performance and drastically reduce the mass required for advanced propulsion systems. The Swedish activities in micropropulsion at The Angstrom Space Technology Centre (ASTC) are outlined. The research targets two major issues: the development of system parts, and the research into integration techniques and strategies. This paper collects a multitude of devices relevant to the micropropulsion system design, together with representative functional demonstrations. The items are mainly intended for chemical micropropulsion systems or fuel-feed systems for electric propulsion. In particular, gas handling devices, sensors, and actuators are presented. These include silicon nozzles, thin film heaters, suspended microcoil heaters, proportional piezoelectric valves, proportional and isolation valves using phase-change material, thermal throttle flow-regulators, high-pressure regulators, 3D-particle filters, and sensors for strain, pressure, flow, and thrust. Moreover, integration techniques and interface structures are presented, for example low-temperature plasma-assisted silicon wafer bonding, multiwafer bonding, thin film soldering, hermetic electric through-wafer via connections, and multiconnector through-wafer vias. Emphasis is on how these items are designed to allow for system integration in a multiwafer silicon stack, comprising a complete micropropulsion system. In this manner, all items form a parts collection available to the system design. This strategy is exemplified by three micropropulsion systems researched at the ASTC. First, the cold/hot gas micropropulsion system is suitable for small spacecraft or when the demands on stability and pointing precision are extreme. The system performance depends strongly on the use of gas flow control. The complete gas handling system of four independent thrusters is integrated in the assembly of four structured silicon wafers. Each independent thruster contains a proportional valve, sensors for pressure, temperature, and thrust feedback, a converging-diverging micronozzle, and a suspended microcoil heater. The mass of the system is below 60 g. In total, this will provide the spacecraft with a safe, clean, low-powered, redundant, and flexible system for three-axis stabilization and attitude control. Second, a Xenon feed system for ion propulsion is heavily miniaturized using microsystems technology. Basically, a micromachined high-pressure regulator receives the gas from the storage, and the flow is further modulated by a thermally controlled flow restrictor. The flow restrictor microsystem comprises narrow ducts, thin film heaters, suspended parts for heat management, and flow sensors. Hereby, the amount of xenon required by the electric propulsion systems can be promptly delivered. The complete system mass is estimated to 150g. Third, within the EU IST program, the ASTC participates in the development of a micro-pyrotechnic actuator system (Micropyros), suitable for short-duration space propulsion. The Micropyros integrate a full matrix of minute solid combustion rocket engines into panels situated on the spacecraft hull. The thrusters can be individually ignited, and each deliver thrust in the millinewton range. The ASTC focuses on the integration of the propulsion part by low-temperature bonding, and the characterization of the complete system.
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