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| 2. |
- Ahlgren, Fredrik, 1980-, et al.
(författare)
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Auto Machine Learning for predicting Ship Fuel Consumption
- 2018
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Ingår i: Proceedings of ECOS 2018 - the 31st International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems. - Guimarães. - 9789729959646
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Konferensbidrag (refereegranskat)abstract
- In recent years, machine learning has evolved in a fast pace as both algorithms and computing power are constantly improving. In this study, a machine learning model for predicting the fuel oil consumption from engine data has been developed for a cruise ship operating in the Baltic Sea. The cruise ship is equipped with legacy volume flow meters and newly installed mass flow meters, as well as an extensive set of logged time series data from the machinery logging system. The model is developed using state-of-the-art Auto Machine Learning tools, which optimises both the model hyper parameters and the model selection by using genetic algorithms. To further increase the model accuracy, a pipeline of different models and pre-processing algorithms is evaluated. An extensive model trained for a certain system can be used for optimisation simulation, as well as online energy efficiency prediction. As the models automatically adapt to noisy sensor data and thus function as a watermark of the machinery system, these algorithms show a potential in predicting ship energy efficiency without installation of additional mass flow meters. All tools used in this study are Open Source tools written in Python and can be applied on board. The study shows great potential for utilising large amounts of already available sensor data for improving the accuracy of the predicted ship energy consumption.
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| 3. |
- Ahlgren, Fredrik, 1980-, et al.
(författare)
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Predicting dynamic fuel oil consumption on ships with automated machine learning
- 2019
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Ingår i: Innovative Solutions for Energy Transitions. - : Elsevier. ; 158, s. 6126-6131
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Konferensbidrag (refereegranskat)abstract
- This study demonstrates a method for predicting the dynamic fuel consumption on board ships using automated machine learning algorithms, fed only with data for larger time intervals from 12 hours up to 96 hours. The machine learning algorithm trained on dynamic data from shorter time intervals of the engine features together with longer time interval data for the fuel consumption. To give the operator and ship owner real-time energy efficiency statistics, it is essential to be able to predict the dynamic fuel oil consumption. The conventional approach to getting these data is by installing additional mass flow meters, but these come with added cost and complexity. In this study, we propose a machine learning approach using auto machine learning optimisation, with already available data from the machinery logging system.
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| 4. |
- Ahlgren, Fredrik, 1980-, et al.
(författare)
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Waste Heat Recovery in a Cruise Vessel in the Baltic Sea by Using an Organic Rankine Cycle : A Case Study
- 2015
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Ingår i: ASME Turbo Expo 2015: Turbine Technical Conference and Exposition. - : ASME Press. - 9780791856673 ; , s. 43392-43416
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Konferensbidrag (refereegranskat)abstract
- Maritime transportation is a significant contributor to SOx, NOx and particle matter emissions, even though it has a quite low CO2 impact. New regulations are being enforced in special areas that limit the amount of emissions from the ships. This fact, together with the high fuel prices, is driving the marine industry towards the improvement of the energy efficiency of current ship engines and the reduction of their energy demand. Although more sophisticated and complex engine designs can improve significantly the efficiency of the energy systems in ships, waste heat recovery arises as the most influent technique for the reduction of the energy consumption. In this sense, it is estimated that around 50% of the total energy from the fuel consumed in a ship is wasted and rejected in fluid and exhaust gas streams. The primary heat sources for waste heat recovery are the engine exhaust and the engine coolant. In this work, we present a study on the integration of an organic Rankine cycle (ORC) in an existing ship, for the recovery of the main and auxiliary engines exhaust heat. Experimental data from the operating conditions of the engines on the M/S Birka Stockholm cruise ship were logged during a port-to-port cruise from Stockholm to Mariehamn over a period of time close to one month. The ship has four main engines Wärtsilä 5850 kW for propulsion, and four auxiliary engines 2760 kW used for electrical consumers. A number of six load conditions were identified depending on the vessel speed. The speed range from 12–14 knots was considered as the design condition, as it was present during more than 34% of the time. In this study, the average values of the engines exhaust temperatures and mass flow rates, for each load case, were used as inputs for a model of an ORC. The main parameters of the ORC, including working fluid and turbine configuration, were optimized based on the criteria of maximum net power output and compactness of the installation components. Results from the study showed that an ORC with internal regeneration using benzene would yield the greatest average net power output over the operating time. For this situation, the power production of the ORC would represent about 22% of the total electricity consumption on board. These data confirmed the ORC as a feasible and promising technology for the reduction of fuel consumption and CO2 emissions of existing ships.
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| 5. |
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| 6. |
- Alfalahi, Alyaa, et al.
(författare)
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Expanding a dictionary of marker words for uncertainty and negation using distributional semantics
- 2015
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Ingår i: EMNLP 2015 - 6th International Workshop on Health Text Mining and Information Analysis, LOUHI 2015 : Proceedings of the Workshop - Proceedings of the Workshop. - : Association for Computational Linguistics. - 9781941643327 ; , s. 90-96
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Konferensbidrag (refereegranskat)abstract
- Approaches to determining the factuality of diagnoses and findings in clinical text tend to rely on dictionaries of marker words for uncertainty and negation. Here, a method for semi-automatically expanding a dictionary of marker words using distributional semantics is presented and evaluated. It is shown that ranking candidates for inclusion according to their proximity to cluster centroids of semantically similar seed words is more successful than ranking them according to proximity to each individual seed word.
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| 7. |
- Ambrazaitis, Gilbert, et al.
(författare)
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Acoustic features of multimodal prominences : Do visual beat gestures affect verbal pitch accent realization?
- 2017
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Ingår i: Proceedings of The 14th International Conference on Auditory-Visual Speech Processing (AVSP2017). - Stockholm : International Speech Communication Association. - 2308-975X.
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Konferensbidrag (refereegranskat)abstract
- The interplay of verbal and visual prominence cues has attracted recent attention, but previous findings are inconclusive as to whether and how the two modalities are integrated in the production and perception of prominence. In particular, we do not know whether the phonetic realization of pitch accents is influenced by co-speech beat gestures, and previous findings seem to generate different predictions. In this study, we investigate acoustic properties ofprominent words as a function of visual beat gestures in a corpus of read news from Swedish television. The corpus was annotated for head and eyebrow beats as well as sentence-level pitch accents. Four types of prominence cues occurredparticularly frequently in the corpus: (1) pitch accent only, (2) pitch accent plus head, (3) pitch accent plus head plus eyebrows, and (4) head only. The results show that (4) differs from (1-3) in terms of a smaller pitch excursion and shorter syllable duration. They also reveal significantly larger pitch excursions in (2) than in (1), suggesting that the realization of a pitch accent is to some extent influenced by the presence of visual prominence cues. Results are discussed in terms of the interaction between beat gestures and prosody with a potential functional difference between head and eyebrow beats.
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| 8. |
- Ambrazaitis, Gilbert, 1979-, et al.
(författare)
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Auditory vs. audiovisual prominence ratings of speech involving spontaneously produced head movements
- 2022
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Ingår i: Proceedings of the 11th International Conference on Speech Prosody : Speech Prosody 2022 - Speech Prosody 2022. - : International Speech Communication Association. - 2333-2042. ; , s. 352-356, s. 352-356
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Konferensbidrag (refereegranskat)abstract
- Visual information can be integrated in prominence perception, but most available evidence stems from controlled experimental settings, often involving synthetic stimuli. The present study provides evidence from spontaneously produced head gestures that occurred in Swedish television news readings. Sixteen short clips (containing 218 words in total) were rated for word prominence by 85 adult volunteers in a between-subjects design (44 in an audio-visual vs. 41 in an audio-only condition) using a web-based rating task. As an initial test of overall rating behavior, average prominence across all 218 words was compared between the two conditions, revealing no significant difference. In a second step, we compared normalized prominence ratings between the two conditions for all 218 words individually. These results displayed significant (or near significant, p
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| 9. |
- Ambrazaitis, Gilbert, et al.
(författare)
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Dip and hat pattern: a phonological contrast of German?
- 2008
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Ingår i: Speech Prosody 2008, Fourth International Conference. - Campinas : The International Speech Communication Association (ISCA). ; , s. 269-272
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Konferensbidrag (refereegranskat)abstract
- Is the high plateau in a ‘hat pattern’ a phonetic artefact, or does it reflect a phonological feature? Can it contrast with a low plateau, i.e., a ‘dip pattern’? The presented perception experiment supports the phonological point of view, since it shows that the dip/hat contrast can disambiguate German oder-constructions, which are interpretable as ‘alternative’ or ‘yes/no-questions’. This specific function may be derived from a more general substance–function relation: While a hat pattern has a ‘bracketing function’, a dip signals detachment.
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| 10. |
- Ambrazaitis, Gilbert, et al.
(författare)
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Expressing ‘confirmation’ in Swedish: the interplay of word and utterance prosody
- 2007
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Ingår i: Proceedings of the 16th International Congress of Phonetic Sciences. - Saarbrücken : Saarland University. - 9783981153507 - 9783981153514 ; , s. 1093-1096
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Konferensbidrag (refereegranskat)abstract
- An exploratory study on the prosodic signaling of ‘confirmation’ in Swedish is presented. Pairs of subjects read short dialogs, constructed around selected target words, in a conversational style. A falling utterance intonation was found on the target word, and the signaling of word prosody (lexical pitch accent) appeared to be, to a certain degree, optional.
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