| 1. |
- Svenmarck, Peter
(författare)
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Human Engineering of Sensor Fusion Systems in Fighter Aircraft
- 2001
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A pressing concern in modern fighter aircraft cockpit design is how to present and reduce large amounts of data obtained from several sensor observations of the same object. Currently, sensor observations are presented individually as overlays or in different displays requiring the pilot to control each sensor and integrate observations. The increased number of sensors and communication networks covering extensive ranges has, however, led to a situation that hampers pilots' situation awareness and decision-making. One approach to support the pilot is automatic information management. Although considerable technological research has been conducted on automatic sensor fusion and process refinement, little is known about how to integrate systems capabilities with pilots' decision-making.This thesis focuses on the factors involved in pilots' control of sensor fusion systems for tracking, classifying,and identifying objects, which are presented on the indicators in the cockpit of fighter aircraft. A cognitive systems engineering perspective was applied, since sensor fusion systems by definition automate parts of the information management. The emphasis in cognitive systems engineering is to create a complementary role for technological solutions and operator competence. A comparison of two major programs on decision support systems shows that striking the right balance between available technology and pilot expertise is important for the development of useful systems.Since little research has directly addressed pilots' control of sensor fusion systems, a conceptual model is presented based on systems characteristics and a review of factors likely to be important. The model shows how pilots' mission goals specify a desired situation awareness that determines the control of sensors. Pilots' control sensor fusion systems by designating important objects and areas, and intervening on exceptions of an essentially autonomous system. The systems support pilots' situation awareness with visualization of information and by improving their evaluation of the situation. Remaining uncertainties that delay action are reduced with suitable strategies. A High Range Resolution (HRR) radar identification system was simulated and evaluated for further understanding of the uncertainty in target identity that is important for pilots. The interface for the HRR system shows how supervisory control of system performance, levels of control, and visualization of conflicts are general factors that may be important for control of sensor fusion systems.The thesis shows that an appropriate function allocation for automatic sensor management may have to consider pilots' individual differences in minimizing goal trees and characterizing situations. Such factors may be important for pilots' expectations on sensor management that makes them use and trust system inferences appropriately. Interviews with pilots can provide some understanding of the factors involved in sensor control. However, since many of the judgments and tactical patterns involved in pilots' decision making are overlearned for efficient automatic performance, they may not be able to explain their behavior in detail. The thesis shows that analyzing pilot performance using neurofuzzy models may be a useful way to describe how situations drive responses. The linguistic form of fuzzy rules gives an intuitive understanding of the relationship in a presentational form that can be integrated with sensor management control rules.
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| 2. |
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| 3. |
- Biel, Lena, et al.
(författare)
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Active perception in a sensor fusion model
- 2002
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- During the last decades the research in the sensor fusion area has mainly been focused on fusion methods and feature selection methods. A possible further development in this area is to incorporate a process referred to as active perception. This means that the system is able to manipulate the sensing mechanisms to create a focus on selected information in the surrounding environment. This process may also be able to handle the feature selection process with respect to which features to be used and/or the number of features to use. This paper presents a model that contains a decision system based on active perception integrated with previous sensor fusion algorithms. The human body has perhaps one of the most advanced perceptual processing systems. The human perception process can be divided into sensation (measurement collection) and perception (interpret the surroundings). During the sensation process a huge amount of data is collected from different sensors that reflect the environment. The information has to be interpreted in an effective way, i.e. in the fusion process. The interpretation together with a decision system to control the sensors to focus on important information will correspond to the (active) perception process. The model presented in this paper capitalizes on the properties presented by the biological counterpart to achieve more human-like processes for a sensor fusion. Finally, the paper presents the testing of the model in two examples. The applications used have a safety approach of fire indication, identification and decision-making. The goal is to enlarge a conventional fire alarm system to not only detect fire, but also to propose different actions for a human in a dangerous area for example.
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| 4. |
- Biel, Lena, et al.
(författare)
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ECG analysis : a new approach in human identification
- 2001
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- In this paper a new approach in human identification is investigated, For this purpose, a standard 12-lead electrocardiogram (ECG) recorded during rest is used. Selected features extracted from the ECG are used to identify a person in a predetermined group. Multivariate analysis is used for the identification task. Experiments show that it is possible to identify a person by features extracted from one lead only. Hence, only three electrodes have to be attached on the person to be identified. This makes the method applicable without too much effort.
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| 5. |
- Carlström, Mattias, et al.
(författare)
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Peritoneal dialysis impairs nitric oxide homeostasis and may predispose infants with low systolic blood pressure to cerebral ischemia
- 2016
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Ingår i: Nitric Oxide - Biology and Chemistry. - : Elsevier BV. - 1089-8603 .- 1089-8611. ; 58, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- Background & purpose Infants on chronic peritoneal dialysis (PD) have an increased risk of developing neurological morbidities; however, the underlying biological mechanisms are poorly understood. In this clinical study, we investigated whether PD-mediated impairment of nitric oxide (NO) bioavailability and signaling, in patients with persistently low systolic blood pressure (SBP), can explain the occurrence of cerebral ischemia. Methods & results Repeated blood pressure measurements, serial neuroimaging studies, and investigations of systemic nitrate and nitrite levels, as well as NO signaling, were performed in ten pediatric patients on PD. We consistently observed the loss of both inorganic nitrate (-17 ± 3%, P < 0.05) and nitrite (-34 ± 4%, P < 0.05) during PD, which may result in impairment of the nitrate-nitrite-NO pathway. Indeed, PD was associated with significant reduction of cyclic guanosine monophosphate levels (-59.4 ± 15%, P < 0.05). This reduction in NO signaling was partly prevented by using a commercially available PD solution supplemented with l-arginine. Although PD compromised nitrate-nitrite-NO signaling in all cases, only infants with persistently low SBP developed ischemic cerebral complications. Conclusions Our data suggests that PD impairs NO homeostasis and predisposes infants with persistently low SBP to cerebral ischemia. These findings improve current understanding of the pathogenesis of infantile cerebral ischemia induced by PD and may lead to the new treatment strategies to reduce neurological morbidities.
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| 6. |
- Iliev, Boyko, et al.
(författare)
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A fuzzy technique for food- and water quality assessment with an electronic tongue
- 2006
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Ingår i: Fuzzy sets and systems (Print). - : Elsevier BV. - 0165-0114 .- 1872-6801. ; 157:9, s. 1155-1168
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Tidskriftsartikel (refereegranskat)abstract
- The problem of food- and water quality assessment is important for many practical applications, such as food industry and environmental monitoring. In this article we present a method for fast online quality assessment based on electronic tongue measurements. The idea is implemented in two steps. First we apply a fuzzy clustering technique to obtain prototypes corresponding to good and bad quality from a set of training data. During the second, online step we evaluate the membership of the current measurement to each cluster and make a decision about its quality. The result is presented to the user in a simple and understandable way, similar to the concept of traffic light signals. Namely, good quality is indicated with by a green light, bad quality with a red one, and a yellow light is a warning signal. The approach is demonstrated in two case studies: quality assessment of drinking water and baby food.
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| 7. |
- Kalaykov, Ivan, et al.
(författare)
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Intelligent feature estimation, based on human's perceptual features
- 2003
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Ingår i: IEEE international workshop on soft computing techniques in instrumentation, measurement and related applications, 2003. - 0780377117 ; , s. 44-48
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Konferensbidrag (refereegranskat)abstract
- The paper presents a relatively new human-computer interaction paradigm, where a human operator's perceptual actions are mimicked by the computer. In this sensor controlled system concept, we estimate a specific feature characterizing, for example, product quality, and apply intelligent analysis and an optimization to assess product quality as acquired by a human expert. The human operator contributes his/her intelligence to this man-machine interaction through learning the measurement system. An illustrative example shows how the human operator's knowledge and experience are learned by a sensor based system within a complex dough mixing optimization process in an industrial bread baking plant. The resulting sensor system acts as an intelligent feature estimator in a complex industrial process for monitoring the dynamical behavior there. The system allows easy sensor observation and makes decisions based on learning interaction with a human.
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| 8. |
- Lindquist, Malin, 1975-
(författare)
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Electronic tongue for water quality assessment
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis describes the work on the development of a new electronic tongue for water quality assessment. The aim of this work is to build a complete system including a sensor and associated data analysis methods which is able to detect quality changes in drinking water and warn the user if the water is not suitable for drinking. Therefore, the main design issues were to build a portable, robust electronic tongue which provides a fast estimate of the water quality rather than identify the type of the contamination. In this sense, the system has a simple interface resembling traffic light signals. The system responds with green light for good water quality, red for bad quality and yellow if the result is uncertain. The electronic tongue sensor is based on voltammetry, which gives a relatively simple and robust system. It is suitable for the considered applications, since it is able to measure small changes in the chemical and micro-organic content in water. These properties are very important for our goal to develop an electronic tongue for water quality assessment. During the development process, the sensor system was modified in order to improve the system’s mobility and robustness. Moreover, the long-term stability and the extent of the sensor drift were evaluated for continuous use. The response time for the sensor is relatively short, but it generates large amounts of data. Therefore, there is a need for pre-processing and feature extraction methods to deal with the complexity of data. This is done with the help of multivariate analysis method. The quality assessment is done with different classification algorithms. We implemented fuzzy clustering and self-organizing maps. In this thesis, two real applications are also considered, where the measurement is taking place in streaming water. In the first case, the electronic tongue could be placed directly at a water tap where random measurements occur. In the second application continuous measurements are performed and information about the sensor drift is used in the data analysis. The evaluation confirmed that the improved sensor system fulfills the requirements for on-line measurements of water quality.
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| 9. |
- Lindquist, Malin, et al.
(författare)
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New sensor system for drinking water quality
- 2004
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Ingår i: Proceedings of the ISA/IEEE Sensors for industry conference, 2004. - 0780381432 ; , s. 30-34
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Konferensbidrag (refereegranskat)abstract
- A sensor system suitable for measuring qualitative changes In the chemical and the bacterial content in drinking water is presented. The sensor, an electronic tongue, is based on a voltammetric technique and is therefore robust, simple and sensitive to small changes of water quality in the measured sample. The sensor system is constructed so the liquid sample will flow through the sensing unit while measuring continuously. The sensor has a solid construction, does not contain any fragile parts and is independent of how it is positioned. This creates new approaches and the sensor can easily be mounted on a underwater vehicle for continuous inspection of drinking water reservoirs and continuously monitor the quality of the water as well as be mounted directly on a drinking water tap.
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| 10. |
- Lindquist, Malin, et al.
(författare)
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Virtual water quality tests with an electionic tongue
- 2001
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Ingår i: Proceedings of the 18th IEEE Instrumentation and measurement technology conference, 2001. IMTC 2001. - 0780366468 ; , s. 1320-1324
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Konferensbidrag (refereegranskat)abstract
- The concept of the “electronic tongue” has been used in some experiments to establish the needs of fast and virtual monitoring of aqueous samples, e.g., in the monitoring of drinking water quality. More specifically, the performance of a proposed multi-electrode sensor system, used for voltammetric analysis of aqueous samples, is described. It is, for example, shown how such an “electronic tongue” can be used to monitor the quality of water in a production plant for drinking water. It is pointed out that conventional techniques often determine single concentration of the measured test while in many areas of measurement technology the methodology to extract adequate information from the environment, e.g., the electronic tongue, makes a total water quality estimate based on predetermined constraints extracted from complicated pattern structures. In this approach, experiments are conducted using an electronic tongue to virtually monitor the drinking water quality, measured from the raw water in the river to the tap water of the consumer. It can be shown that a system based on the proposed multi-electrode virtual sensor system is able to detect water quality changes. In these experiments, with the use of signal analysis and statistical multivariate methods we are able to estimate the water quality
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