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| 2. |
- Nygren, Ingemar, et al.
(författare)
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FDM and FEM filters in terrain navigation
- 2007
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Ingår i: Proceedings of the Institute of Navigation, National Technical Meeting. ; , s. 1155-1166
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Konferensbidrag (refereegranskat)abstract
- Terrain navigation in nearly flat areas is a difficult task since the probability density function (PDF) of the vehicle position typically is multimodal due to terrain repeatability. Traditional methods as TERCOM, TERPROM or similar methods fail in such situations. Instead, Bayesian methods have proven to be useful. A prerequisite for all terrain navigation methods in nearly flat areas is extremely informative measurements of the terrain topography. In addition, methods for efficiently propagating the multimodal probability density function of the vehicle are needed. This paper describes a Bayesian filtering method based on finite differences or finite elements that can efficiently handle the propagation of multimodal PDFs. The paper also goes briefly into the theory behind the filters starting with a problem formulation by stochastic differential equations. The proposed filtering method has been successfully tested with real measurement data and maps and it is fast enough to allow the filter to be used in real time even for fast vehicles. Besides being optimal, the method is highly robust, conditions for stability are well understood, and error estimates are available. Another advantage of the method is that readily available professional software for solving partial differential equations can be adopted.
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| 4. |
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| 5. |
- Nygren, Ingemar, et al.
(författare)
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Robust Terrain Navigation with the Correlation Method for High Position Accuracy
- 2003
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Ingår i: OCEANS 2003 Marine Technology and Ocean Science Conference. - : IEEE. ; , s. 1269-1277
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Konferensbidrag (refereegranskat)abstract
- Describes the correlation method for determining the position of an autonomous underwater vehicle (AUV) in shallow waters. The method is conceptually simple. It involves measuring the seabed topography with a few sonar pings over a limited area by an ordinary bathymetric multibeam sonar. These measurements are then correlated with existing underwater maps. The position estimate from the correlation method can often be used as it is or fused by a linear Kalman filter with almost optimal performance. The paper also shows results from a sea-trial with the Reson SeaBat 8001 multibeam bathymetric sonar. The achieved 1/spl sigma/-circular accuracy is 0.3-0.4 metre in the north of the Baltic Sea.
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| 6. |
- Nygren, Ingemar Tobias, et al.
(författare)
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Effects of tasting technique : sequential tasting vs. mixed tasting – on perception of dry white wine and blue mould cheese
- 2003
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Ingår i: Food Service Technology. - : Wiley. - 1471-5732 .- 1471-5740. ; 3:2, s. 61-69
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Tidskriftsartikel (refereegranskat)abstract
- The object of this study was to evaluate by means of descriptive sensory analysis the effect of mixed tasting on the perception of dry white wine and blue mould cheese, and to establish whether the tasting technique (sequential vs. mixed tasting) significantly affects this perception. A Swedish blue mould cheese, Bredsjö Blå, and a French blue mould cheese, Roquefort Société, and five commercial types of dry white wine were used. The same panel, selected and trained according to ISO standards, as in Nygren et al. (2002, 2003) carried out the descriptive analyses by means of a mixed tasting technique. The panel scored the same attributes for both cheese and wine as in Nygren et al. (2002, 2003). In general, the original wine attribute scores decreased more by means of mixed tasting technique than by means of sequential, while few changes of the original cheese attribute scores were observed. Overall, mixed tasting gave greater decreasing changes than sequential tasting.
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| 7. |
- Nygren, Ingemar Tobias, et al.
(författare)
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Flavor changes produced by wine and food interactions : Chardonnay wine and Hollandaise sauce
- 2001
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Ingår i: Journal of sensory studies. - 0887-8250 .- 1745-459X. ; 16:5, s. 461-470
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Tidskriftsartikel (refereegranskat)abstract
- The change in flavor produced by food and wine interactions was explored using descriptive analysis of Hollandaise sauce prepared with two levels of butter and three wines: a Chardonnay which was unoaked, acidified with 1.5 g/L citric acid or aged in oak for one year. To measure the effect of the sauce on wine flavor, the intensity of citrus, buttery, and toasted flavor by mouth and of sourness and bitterness was rated in each wine before and after each sauce was tasted. In a second testing series, lemon, brothy and creamy-butter flavor by mouth and creamy mouthfeel were rated for each sauce before and after tasting each wine. The effect of Hollandaise sauce on wine flavor was greater than the effect of wines on sauce flavor, with the higher fat sauce having a slightly larger effect overall. Sour and bitter flavors of the wines decreased in intensity after Hollandaise sauce was tasted, while the buttery flavor by mouth increased. The toasted flavor decreased significantly in the oaked wine after the sauce had been tasted, while citrus flavor was decreased only for the unoaked wine.
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| 8. |
- Nygren, Ingemar Tobias, et al.
(författare)
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Perceived flavour changes in blue mould cheese after tasting white wine
- 2003
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Ingår i: Food Service Technology. - : Wiley. - 1471-5732 .- 1471-5740. ; 3:3-4, s. 143-150
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Tidskriftsartikel (refereegranskat)abstract
- The object of this study was to evaluate by descriptive sensory analysis how prior tasting of dry white wine affects the sensory perception of blue mould cheese. Two blue mould cheeses, a Swedish one, Bredsjö Blå (Bredsjö Mjölkfår AB, Sweden), and a French one, Roquefort (Roquefort Société, France), were tasted in combination with five commercial dry white wines. Nine trained assessors assessed the cheeses and the wines in sequential order, with the cheese being assessed before and after tasting the wines. The main findings were that the most pronounced characteristics of the Bredsjö Blå, such as buttery and woolly flavours, and the saltiness and sour taste of the Roquefort, decreased after tasting dry white wine.
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| 9. |
- Nygren, Ingemar Tobias, et al.
(författare)
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Perceived flavour changes in white wine after tasting blue mould cheese
- 2002
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Ingår i: Food Service Technology. - : Wiley. - 1471-5732 .- 1471-5740. ; 2:4, s. 163-171
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Tidskriftsartikel (refereegranskat)abstract
- The object of this study was to evaluate by descriptive sensory analysis how the sensory perception of dry white wines was affected by prior tasting of blue mould cheese. Trained assessors profiled five commercial white wines before and after tasting each of two blue mould cheeses. The study showed that descriptive sensory analysis could be used to quantify changes in the perception of white wines after the consumption of cheese. For all five wines the main findings were that most of the intensities of perceived flavours and acidity decreased after tasting blue mould cheese.
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| 10. |
- Nygren, Ingemar Tobias, 1968-
(författare)
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Sensory evaluation and consumer preference of wine and food combinations : influences of tasting techniques
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The entire project consists of five studies. Descriptive sensory analyses were performed on combinations of five dry white wines and either Hollandaise sauce with two levels of fat or two blue mould cheeses. Assessments were carried out by a student panel and by a selected and trained panel. The effect of tasting technique on defined attributes was investigated: firstly by switching the order of serving wine and sauce or wine and cheese within the sequential tasting technique and secondly by mixing wine and cheese in the mouth, mixed tasting technique. Finally, consumers in Norway and Sweden, accustomed to drinking wine and eating blue mould cheese, carried out a preference test on wine and cheese combinations. The perception of the white wine characteristics generally decreased in intensity after the tasting of Hollandaise sauce. The buttery flavour of wine, however, increased after the tasting of Hollandaise sauce. Generally, the perception of dry white wine flavours (blackcurrant leaf, oak, mineral, spice) decreased after the tasting of both cheeses, whether the tasting was sequential or mixed. Few changes in the perception of the sauce attributes were observed after the tasting of white wine. However, lemon flavour of Hollandaise sauce decreased after the tasting of oaked wine. The perception of pronounced cheese flavours (butter, wool, basement-like) and tastes (sour and salty) decreased after the tasting of dry white wine for both sequential and mixed tasting whereas the other attributes remained unchanged. The perception of the wine attributes decreased more in the case of mixed tasting technique than in the case of sequential, while few changes in the perception of the cheese attributes were observed. Sweetness, however, increased in the Roquefort cheese mixed with certain wines. The consumers in both Norway and Sweden usually (80%) drank dry red wine with blue mould cheese. The Norwegian consumers preferred dry red wines to sweet red wines in combination with blue mould cheese. The wines rather than the cheeses separated the preferences regarding the combinations.
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