| 1. |
- Alves, G.R., et al.
(författare)
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Using VISIR in a large undergraduate course : Preliminary assessment results
- 2011
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Konferensbidrag (refereegranskat)abstract
- The use of remote labs in undergraduate courses has been reported in literature several times since the mid 90's. Nevertheless, very few articles present results about the learning gains obtained by students using them, especially with a large number of students, thus suggesting a lack of data concerning their pedagogical effectiveness. This paper addresses such a gap by presenting some preliminary results concerning the use of a remote laboratory, known as VISIR, in a large undergraduate course on Applied Physics, with over 500 students enrolled.
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| 2. |
- A.V., Fidalgo, et al.
(författare)
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Adapting remote labs to learning scenarios : Case studies using VISIR and remotElectLab
- 2014
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Ingår i: Revista Iberoamericana de Tecnologias del Aprendizaje. - : Education Society of IEEE (Spanish Chapter). - 1932-8540. ; 9:1, s. 33-39
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Tidskriftsartikel (refereegranskat)abstract
- Remote laboratories are an emergent technological and pedagogical tool at all education levels, and their widespread use is an important part of their own improvement and evolution. This paper describes several issues encountered on laboratorial classes, on higher education courses, when using remote laboratories based on PXI systems, either using the VISIR system or an alternate in-house solution. Three main issues are presented and explained, all reported by teachers, that gave support to students' use of remote laboratories. The first issue deals with the need to allow students to select the actual place where an ammeter is to be inserted on electric circuits, even incorrectly, therefore emulating real-world difficulties. The second one deals with problems with timing when several measurements are required at short intervals, as in the discharge cycle of a capacitor. In addition, the last issue deals with the use of a multimeter in dc mode when reading ac values, a use that collides with the lab settings. All scenarios are presented and discussed, including the solution found for each case. The conclusion derived from the described work is that the remote laboratories area is an expanding field, where practical use leads to improvement and evolution of the available solutions, requiring a strict cooperation and information-sharing between all actors, i.e., developers, teachers, and students.
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| 3. |
- Fidalgo, André, et al.
(författare)
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Using remote labs to serve different teacher's needs : A case study with VISIR and RemotElectLab
- 2012
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Konferensbidrag (refereegranskat)abstract
- Remote Laboratories are an emergent technological and pedagogical tool at all education levels, and their widespread use is an important part of their own improvement and evolution. This paper describes several issues encountered on laboratorial classes, on higher education courses, when using remote laboratories based on PXI systems, either using the VISIR system or an alternate in-house solution. Three main issues are presented and explained, all reported by teachers that gave support to students use of remote laboratories. The first issue deals with the need to allow students to select the actual place where an ammeter is to be inserted on electric circuits, even incorrectly, therefore emulating real world difficulties. The second one deals with problems with timing when several measurements are required at short intervals, as in the discharge cycle of a capacitor. And the last issue deals with the use of a multimeter in DC mode when reading AC values, a use that collides with the lab settings. All scenarios are presented and discussed including the solution found for each case. The conclusion derived from the described work is that the remote laboratories area is an expanding field, where practical use leads to improvement and evolution of the available solutions, requiring a strict cooperation and information sharing between all actors, i.e. developers, teachers and students.
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| 4. |
- Garcia-Loro, F., et al.
(författare)
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PILAR : A Federation of VISIR Remote Laboratory Systems for Educational Open Activities
- 2018
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Ingår i: Proceedings of 2018 IEEE International Conference on Teaching, Assessment, and Learning for Engineering, TALE 2018. - : Institute of Electrical and Electronics Engineers Inc.. - 9781538665220 ; , s. 134-141
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Konferensbidrag (refereegranskat)abstract
- Social demands have promoted an educational approach based on an 'anywhere and anytime' premise. Remote laboratories have emerged as the answer to the demands of technical educational areas for adapting themselves to this scenario. The result has not only benefit distance learning students but has provided new learning scenarios both for teachers and students as well as allowing a flexible approach to experimental topics. However, as any other solution for providing practical scenarios (hands-on labs, virtual labs or simulators), remote labs face several constraints inherited from the subsystems of its deployment - hardware (real instruments, equipment and scenario) and software (analog/digital conversions, communications, workbenches, etc.}. This paper describes the Erasmus+ project Platform Integration of Laboratories based on the Architecture of visiR (PILAR) which deals with several units of the federation installed in different educational institutions and devoted to analog electronics and electrical circuits. Based on the limitations of remote labs, the need for the federation will be justified and its benefits will be described by taking advantage of its strengths. The challenges that have come up during the different stages and the different approaches to design are also going to be described and analyzed. © 2018 IEEE.
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| 5. |
- Turkenburg, Wim C, et al.
(författare)
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Renewable Energy Technologies
- 2000
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Ingår i: World energy assessment: energy and the challenge of sustainability. - 9211261260 ; , s. 219-272
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Bokkapitel (refereegranskat)abstract
- In 1998 renewable energy sources supplied 56 ± 10 exajoules,or about 14 percent of world primary energy consumption. Thesupply was dominated by traditional biomass (38 ± 10 exajoules a year. Other major contributions came from large hydropower (9 exajoules a year) and from modern biomass (7 exajoules). The contribution of all other renewables — small hydropower, geothermal, wind, solar, and marineenergy — was about 2 exajoules. That means that the energy supply from new renewables was about 9 exajoules (about 2 percent of world consumption). The commercial primary energy supply from renewable sources was 27 ± 6 exajoules (nearly 7 percent of world consumption), with 16 ± 6 exajoules from biomass. Renewable energy sources can meet many times the present world energy demand, so their potential is enormous. They can enhance diversity in energy supply markets, secure long-term sustainable energy supplies, and reduce local and global atmospheric emissions. They can also provide commercially attractive options to meet specific needs for energy services (particularly in developing countries and rural areas), create new employment opportunities, and offer possibilities for local manufacturing of equipment. There are many renewable technologies. Although often commerciallyavailable, most are still at an early stage of development and not technically mature. They demand continuing research, development, and demonstration efforts. In addition, few renewable energy technologies can compete with conventional fuels on cost, except in some niche markets. But substantial cost reductions can be achieved for most renewables, closing gaps and making them more competitive. That will require further technology development and market deployment — and boosting production capacities to mass production. For the long term and under very favourable conditions, the lowest cost to produce electricity might be $0.01–0.02 a kilowatt-hour for geothermal, $0.03 a kilowatt-hour for wind and hydro, $0.04 a kilowatt-hour for solar thermal and biomass, and $0.05–0.06 a kilowatt-hour for photovoltaics and marine currents. The lowest cost to produce heat might be $0.005 a kilowatt-hour for geothermal, $0.01 a kilowatt-hour for biomass, and $0.02–0.03 a kilowatt-hour for solar thermal. The lowest cost to produce fuels might be $1.5 a gigajoule for biomass, $6–7 a gigajoule for ethanol, $7–10 a gigajoule for methanol, and $6–8 a gigajoule for hydrogen. Scenarios investigating the potential of renewables reveal that they might contribute 20–50 percent of energy supplies in the second half of the 21st century. A transition to renewables-based energy systems would have to rely on: Successful development and diffusion of renewable energy technologies that become more competitive through cost reductions from technological and organisational developments. Political will to internalise environmental costs and other externalities that permanently increase fossil fuel prices. Many countries have found ways to promote renewables. As renewable energy activities grow and require more funding, the tendency in many countries is to move away from methods that let taxpayers carry the burden of promoting renewables, towards economic and regulatory methods that let energy consumers carry the burden.
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| 6. |
- Buendia, Ruben, 1982, et al.
(författare)
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Estimation of body fluids with bioimpedance spectroscopy: state of the art methods and proposal of novel methods
- 2015
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Ingår i: Physiological Measurement. - : IOP Publishing. - 0967-3334 .- 1361-6579. ; 36:10
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Tidskriftsartikel (refereegranskat)abstract
- Determination of body fluids is a useful common practice in determination of disease mechanisms and treatments. Bioimpedance spectroscopy (BIS) methods are non-invasive, inexpensive and rapid alternatives to reference methods such as tracer dilution. However, they are indirect and their robustness and validity are unclear. In this article, state of the art methods are reviewed, their drawbacks identified and new methods are proposed. All methods were tested on a clinical database of patients receiving growth hormone replacement therapy. Results indicated that most BIS methods are similarly accurate (e.g. < 0.5 +/- 3.0% mean percentage difference for total body water) for estimation of body fluids. A new model for calculation is proposed that performs equally well for all fluid compartments (total body water, extra-and intracellular water). It is suggested that the main source of error in extracellular water estimation is due to anisotropy, in total body water estimation to the uncertainty associated with intracellular resistivity and in determination of intracellular water a combination of both.
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| 7. |
- Seoane, Fernando, et al.
(författare)
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Slightly superior performance of bioimpedance spectroscopy over single frequency regression equations for assessment of total body water.
- 2015
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Ingår i: Engineering in Medicine and Biology Society (EMBC), 2015 37th Annual International Conference of the IEEE. 25-29 Aug. 2015, Milan, Italy.. - : IEEE. - 1094-687X .- 1558-4615. - 9781424492718 - 9781424492701 ; 2015, s. 3707-10
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Konferensbidrag (refereegranskat)abstract
- Electrical bioimpedance has been used for several decades to assess body fluid distribution and body composition by using single frequency and bioimpedance spectroscopic (BIS) techniques. It remains uncertain whether BIS methods have better performance compare to single frequency regression equations. In this work the performance of two BIS methods and four different 50 kHz single frequency prediction equations was studied in a data set of wrist-to-ankle tetrapolar BIS measurements (5-1000 kHz) together with reference values of total body water obtained by tritium dilution in 92 patients. Data were compared using regression techniques and Bland-Altman plots. The results of this study showed that all methods produced similarly high correlation and concordance coefficients, indicating good accuracy as a method. Limits of agreement analysis indicated that the population level performance of Sun's prediction equations was very similar to the performance of both BIS methods. However, BIS methods in practice have slightly better predictive performance than the single-frequency equations as judged by higher correlation and the limits of agreement from the Bland-Altman analysis. In any case, the authors believe that an accurate evaluation of performance of the methods cannot be done as long as the evaluation is done using Bland-Altman analysis, the commonly accepted technique for this kind of performance comparisons.
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| 8. |
- Seoane, Fernando, et al.
(författare)
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Mean Expected Error in Prediction of Total Body Water: A True Accuracy Comparison between Bioimpedance Spectroscopy and Single Frequency Regression Equations
- 2015
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Ingår i: Biomed Research International. - : Hindawi Limited. - 2314-6133 .- 2314-6141. ; 2015:Article ID 656323
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Tidskriftsartikel (refereegranskat)abstract
- For several decades electrical bioimpedance (EBI) has been used to assess body fluid distribution and body composition. Despite the development of several different approaches for assessing total body water (TBW), it remains uncertain whether bioimpedance spectroscopic (BIS) approaches are more accurate than single frequency regression equations. The main objective of this study was to answer this question by calculating the expected accuracy of a single measurement for different EBI methods. The results of this study showed that all methods produced similarly high correlation and concordance coefficients, indicating good accuracy as a method. Even the limits of agreement produced from the Bland-Altman analysis indicated that the performance of single frequency, Sun's prediction equations, at population level was close to the performance of both BIS methods; however, when comparing the Mean Absolute Percentage Error value between the single frequency prediction equations and the BIS methods, a significant difference was obtained, indicating slightly better accuracy for the BIS methods. Despite the higher accuracy of BIS methods over 50 kHz prediction equations at both population and individual level, the magnitude of the improvement was small. Such slight improvement in accuracy of BIS methods is suggested insufficient to warrant their clinical use where the most accurate predictions of TBW are required, for example, when assessing over-fluidic status on dialysis. To reach expected errors below 4-5%, novel and individualized approaches must be developed to improve the accuracy of bioimpedance-based methods for the advent of innovative personalized health monitoring applications.
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| 9. |
- Zhu, B., 0, et al.
(författare)
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Electrolysis studies based on ceria-based composite low temperature ceramic fuel cells
- 2005
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Ingår i: In proceedings of The 4th Sino-Swedish fuel cell workshop and joint Energy-Environment Forum. Ed. by Zhu, B. , Mao, Z. , Mellander, Bengt Erik, Sundén, B. , Zhang, M..
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Konferensbidrag (refereegranskat)
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| 10. |
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