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- Dodoo, Ambrose, 1979-, et al.
(author)
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Final energy savings and cost-effectiveness of deep energy renovation of a multi-storey residential building
- 2017
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In: Energy. - : Pergamon Press. - 0360-5442 .- 1873-6785. ; 135, s. 563-576
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Journal article (peer-reviewed)abstract
- In this study we present a method for analysis of cost-effectiveness of end-use energy efficiency measures and demonstrate its application for modelling a wide range of energy renovation measures for a typical 1970s multi-family building in Sweden. The method integrates energy balance and bottom-up economic calculations considering total and marginal investment costs of energy efficiency measures as well as net present value of total and marginal savings of the measures. The energy renovation measures explored include additional insulation to basement walls, exterior walls, and attic floor, improved new windows, efficient electric appliances and lighting, efficient water taps, glazed enclosed balcony systems, and exhaust air ventilation heat recovery systems. The measures are analysed first individually and then designed to form economic packages. Our results show that improved windows give the biggest single final energy savings while resource-efficient taps is the most cost-effective measure for the building. We find that the cost-effectiveness of the energy renovation measures is sensitive to real discount rates and energy price increases. Cost-optimal final heat savings varies between 34% and 51%, depending on the choice of real discount rate and energy price increase. The corresponding electricity savings varies between 35% and 43%. This study shows a method and the significance of various technical and economic-related parameters in achieving deep energy savings cost-efficiently.
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| 3. |
- Sinander, Erik, 1986-
(author)
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Omöjligt att samtycka till staplad visstid
- 2020
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In: Lag & avtal. - 0349-7143. ; :3-4, s. 31-31
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Journal article (pop. science, debate, etc.)abstract
- En arbetstagare kan aldrig samtycka till stapling av visstid på det sätt som accepteras i spansk rätt. Trots det är spansk domstol inte skyldig att låta EU-rätten få företräde, eftersom förbudet mot stapling inte har direkt effekt. Det fastslog EU-domstolen i en dom om offentliganställda spanska arbetstagare.
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- Andrenucci, Andrea
(author)
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Creating a Bilingual Psychology Lexicon for Cross Lingual Question Answering - A Follow up Study
- 2010
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In: Proceedings of the 6th International Conference on Web Information Systems and Technologies. - : INSTICC Press. ; , s. 95-102
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Conference paper (peer-reviewed)abstract
- This paper discusses a follow-up study aimed at investigating the extraction of word relations from a medical parallel corpus in the field of Psychology. Word relations are extracted in order to create a bilingual lexicon for cross lingual question answering between Swedish and English on a medical portal. Six different variants of the corpus were utilized: word inflections with and without POS tagging, syntactically parsed word inflections, lemmas with and without POS tagging, syntactically parsed lemmas. The purpose of the study was to analyze the quality of the word relations obtained from the different versions of the corpus and to understand which version of the corpus was more suitable for extracting a bilingual lexicon in the field of psychology. The word alignments were evaluated with the help of reference data (gold standard) and with measures such as precision and recall.
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| 13. |
- Ghaviha, Nima, et al.
(author)
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Optimal Control of a Battery Train Using Dynamic Programming
- 2015
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Conference paper (other academic/artistic)abstract
- Electric propulsion system in trains has the highest efficiency compared to other propulsion systems (i.e. steam and diesel). Still, electric trains are not used on all the routes, due to the high setup and maintenance cost of the catenary system. Energy storage technologies and the battery driven trains however, make it possible to have the electric trains on the non-electrified routes as well. High energy consumption of the electric trains, makes the energy management of such trains crucial to get the best use of the energy storage device. This paper suggests an algorithm for the optimal control of the catenary free operation of an electric train equipped with an onboard energy storage device. The algorithm is based on the discrete dynamic programming and Bellman’s backward approach. The objective function is to minimize the energy consumption, i.e. having the maximum battery level left at the end of the trip. The constraints are the trip time, battery capacity, local speed limits and limitations on the traction motor. Time is the independent variable and distance, velocity and battery level are the state variables. All of the four variables are discretized which results in some inaccuracy in the calculations, which is discussed in the paper. The train model and the algorithm are based on the equations of motion which makes the model adjustable for all sorts of electric trains and energy storage devices. Moreover, any type of electrical constraints such as the ones regarding the voltage output of the energy storage device or the power output can be enforced easily, due to the nature of the dynamic programming.
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| 14. |
- Ghaviha, Nima, et al.
(author)
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Optimal Control of an EMU Using Dynamic Programming and Tractive Effort as the Control Variable
- 2015
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In: Proceedings of the 56th SIMS. - Linköping University Electronic Press, Linköpings universitet : Linköping University Electronic Press. - 9789176859001 ; , s. 377-382
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Conference paper (peer-reviewed)abstract
- Problem of optimal train control with the aim of minimizing energy consumption is one of the old optimal control problems. During last decades different solutions have been suggested based on different optimization techniques, each including a certain number of constraints or different train configurations, one being the control on the tractive effort available from traction motor. The problem is previously solved using dynamic programming for trains with continuous tractive effort, in which velocity was assumed to be the control variable. The paper at hand presents a solution based on dynamic programming for solving the problem for trains with discrete tractive effort. In this approach, tractive effort is assumed to be the control variable. Moreover a short comparison is made between two approaches regarding accuracy and ease of application in a driver advisory system.
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| 15. |
- Ghaviha, Nima, et al.
(author)
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Review of Application of Energy Storage Devices in Railway Transportation
- 2017
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In: Energy Procedia. - : Elsevier BV. - 1876-6102.
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Conference paper (peer-reviewed)abstract
- Regenerative braking is one of the main reasons behind the high levels of energy efficiency achieved in railway electric traction systems. During regenerative braking, the traction motor acts as a generator and restores part of the kinetic energy into electrical energy. To use this energy, it should be either fed back to the power grid or stored on an energy storage system for later use. This paper reviews the application of energy storage devices used in railway systems for increasing the effectiveness of regenerative brakes. Three main storage devices are reviewed in this paper: batteries, supercapacitors and flywheels. Furthermore, two main challenges in application of energy storage systems are briefly discussed. © 2017 The Authors.
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| 16. |
- Ghaviha, Nima, et al.
(author)
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Speed profile optimization of an electric train with on-board energy storage and continuous tractive effort
- 2016
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In: 2016 International Symposium on Power Electronics, Electrical Drives, Automation and Motion, SPEEDAM 2016.
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Conference paper (peer-reviewed)abstract
- Electric traction system is the most energy efficient traction system in railways. Nevertheless, not all railway networks are electrified, which is due to high maintenance and setup cost of overhead lines. One solution to the problem is battery-driven trains, which can make the best use of the electric traction system while avoiding the high costs of the catenary system. Due to the high power consumption of electric trains, energy management of battery trains are crucial in order to get the best use of batteries. This paper suggests a general algorithm for speed profile optimization of an electric train with an on-board energy storage device, during catenary-free operation on a given line section. The approach is based on discrete dynamic programming, where the train model and the objective function are based on equations of motion rather than electrical equations. This makes the model compatible with all sorts of energy storage devices. Unlike previous approaches which consider trains with throttle levels for tractive effort, the new approach considers trains in which there are no throttles and tractive effort is controlled with a controller (smooth gliding handle with no discrete levels). Furthermore, unlike previous approaches, the control variable is the velocity change instead of the applied tractive effort. The accuracy and performance of the discretized approach is evaluated in comparison to the formal movement equations in a simulated experimented using train data from the Bombardier Electrostar series and track data from the UK.
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| 20. |
- Sinander, Erik, 1986-
(author)
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Pensionsstiftelse förlorar EU-tvist värd 100 miljoner pund
- 2019
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In: Lag & avtal: arbetsrättslig tidskrift. - 0349-7143. ; :12-13, s. 56-57
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Journal article (pop. science, debate, etc.)abstract
- Det var fel att retroaktivt höja pensionsåldern för kvinnor till 65 år, även om syftet var att uppnå likabehandling. Det konstaterar EU-domstolen i en tvist vars utslag kan kosta en engelsk pensionsfund 100 miljoner brittiska pund.
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| 22. |
- Wang, Zhichao, et al.
(author)
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Techno-economic comparison on charging modes of battery heavy-duty vehicles in short-haul delivery: A case study of China
- 2023
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In: Journal of Cleaner Production. - : ELSEVIER SCI LTD. - 0959-6526 .- 1879-1786. ; 425
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Journal article (peer-reviewed)abstract
- It is critical to arrange appropriate charging infrastructure in advance to decarbonise heavy freight through electrification. Based on the same service level, this study conducted a techno-economic comparison of charging modes for battery heavy-duty vehicles in short-haul delivery, covering the broadest range of charging modes, including slow, fast (150 kW), fast (350 kW), swap, and overhead catenary. The techno-economic performance is obtained by a model composed of five evaluation indicators, in which the ratio of service capacity to cost and the average financial net present value are specific. The factors influencing the techno-economic performance of charging modes are further explored based on case analysis. Results show that the charging modes of slow, fast (150 kW), fast (350 kW), swap, and overhead catenary are not profitable under the corresponding facility utilisation rates of 40%, 20%, 20%, 30%, and 70%, or under operating years of 5, 3, 2, 4, and 12 years. Fast charging, at both 150 and 350 kW, has a better advantage in profitability based on the highest average financial net present value. Swap charging is best regarding energy supplement efficiency, but it is not profitable when the battery swapping price is less than 0.8 CNY/kWh. Overhead catenary charging is the most effective system per unit cost due to the highest ratio of service capacity to cost. The insights, the precise prediction of the charging demand, the focus on the charging price, and the comprehensive improvement in the facility utilisation rate are crucial for the success of charging service providers.
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