| 1. |
- Bengtsson, Johan, et al.
(författare)
-
Modeling of Driver's Longitudinal Behavior
- 2003
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Ingår i: Nonlinear and Hybrid Systems in Automotive Control. - 076801137X ; , s. 41-58
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- In the last years, many vehicle manufacturers have introduced advancedriver support in some of their automobiles. One of those new featuresis Adaptive Cruise Control (ACC), which extends the conventionalcruise control system to control of relative speed and distance toother vehicles. In order to design an ACC controller it is suitable tohave a model on drivers' behavior. Our approach to find dynamicalmodels of the drivers' behavior was to use system identification.Basic data analysis was made by means of system identificationmethodology, and several models of drivers' longitudinal behavior areproposed, including both linear regression models and subspace basedmodels. Detection when a driver is changing his behavior in varioussituations to a deviant behavior is useful. To that purpose a GARCHmodel was used to model the driver in arousal situations, where thedriver changes behavior, is proposed.
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| 2. |
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| 3. |
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| 4. |
- Andersson, Sarah, et al.
(författare)
-
Malmbanan Diaries
- 2010
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This booklet is a report for a case study visit during four day field trip, a group of nine PhD students and their supervisors – all part of the National Research School for Architecture and Planning in the Urban Landscape, APULA – set out to explore what may be considered the outback of Western Europe’s conurbations, the transnational region of Kiruna -Narvik.Both “remote” and “resourceful”, “threatened” and “thriving” (equally relative notions), this region seemed to offer possibilities to reflect upon many of the current tendencies influencing contemporary planning practice and research.
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| 5. |
- Bengtsson, Johan, et al.
(författare)
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Closed-loop Combustion Control of Homogeneous Charge Compression Ignition (HCCI) Engine Dynamics
- 2004
-
Ingår i: International Journal of Adaptive Control and Signal Processing. - : Wiley. - 0890-6327 .- 1099-1115. ; 18:2, s. 167-179
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Tidskriftsartikel (refereegranskat)abstract
- Homogeneous charge compression ignition (HCCI) is a hybrid of the sparkignition and compression ignition engine concepts. As in a sparkignition engine, a homogeneous fuel-air mixture is created in theinlet system. During the compression stroke the temperature of themixture increases and reaches the point of auto ignition, just as in acompression ignition engine (or Diesel). One challenge with HCCI engines isthe need for good timing control of the combustion. Auto ignition of ahomogeneous mixture is very sensitive to operating condition. Evensmall variations of the load can change the timing from too early totoo late combustion. Thus a fast combustion timing control isnecessary since it sets the performance limitation of the loadcontrol. As measurement for combustion timing feedback, the crank angleof 50% burnt has been used. This paper performs a comparative studyof different cylinder-pressure based methods for estimating the crankangle of 50% burnt. The estimates are compared in terms of accuracy,robustness and feasibility for cycle-to-cycle real-time control.Dynamic models of CA50 are estimated using system identification asa means to find models relevant to engine control.
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| 6. |
- Bengtsson, Johan, et al.
(författare)
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Control of Homogeneous Charge Compression Ignition (HCCI) Engine Dynamics
- 2004
-
Ingår i: Proceedings of the 2004 American Control Conference, ACC : June 30 - July 2, 2004, Boston Sheraton Hotel, Boston, Massachusetts. - 0743-1619. - 0780383354 ; 5, s. 4048-4053
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Konferensbidrag (refereegranskat)abstract
- The Homogeneous Charge Compression Ignition (HCCI) combustionconcept lacks direct ignition timing control, instead the autoignition depends on the operating condition. Since auto ignition of ahomogeneous mixture is very sensitive to operating conditions, a fastcombustion timing control is necessary for reliable operation. Hence,feedback is needed and the crank angle of 50% burnt (CA50) has provedto be a reliable feedback indicator of on-going combustion inpractice. CA50 or other methods for detecting on-going cylinderpressure used in the feedback control of a HCCI engine all rely onpressure sensors. This paper presents a newcandidate for control of HCCI engine by using the electronicconductive properties in the reaction zone. This phenomenon is calledion current. This paper perform combustion timing control based on ioncurrent and compare it with control based on pressure sensor. Thecombustion timing control is performed on cycle-to-cycle basis and the engine is a one-cylinder version of a heavy duty engine equipped with a port injection system using dual fuels.
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| 7. |
- Bengtsson, Johan, et al.
(författare)
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Hybrid Control of Homogeneous Charge Compression Ignition (HCCI) Engine Dynamics
- 2006
-
Ingår i: International Journal of Control. - : Informa UK Limited. - 0020-7179 .- 1366-5820. ; 79:5, s. 422-448
-
Tidskriftsartikel (refereegranskat)abstract
- The homogeneous charge compression ignition ( HCCI) combustion engine principle lacks direct ignition timing control, instead the auto-ignition depends on the operating condition. Since auto-ignition of a homogeneous mixture is very sensitive to operating conditions, fast combustion phasing control is necessary for reliable operation. For this paper, a six-cylinder heavy-duty HCCI engine was controlled on a cycle-to-cycle basis in real time. Sensors, actuators and control structures for control of the HCCI combustion were compared. Among several actuators for HCCI engine control suggested, two actuators were compared-i.e., dual-fuel actuation and variable valve actuation (VVA). As for control principles, model predictive control (MPC) has several desirable features and today MPC can be applied to relatively fast systems, such as VVA and dual-fuel actuation. For sensor feedback control of the HCCI engine, cylinder pressure and ion current - i.e., the electronic conductive properties in the reaction zone - were compared. Combustion phasing control based on ion current was compared to control based on cylinder pressure. For the purpose of control synthesis requiring dynamic models, system identification provided models of the HCCI combustion, the models being validated by stochastic model validation. With such models providing a basis for model-based control, MPC control results were compared to PID and LQG control results. While satisfying the constraints on cylinder pressure, both control of the combustion phasing and control of load torque was achieved with simultaneous minimization of the fuel consumption and emissions.
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| 8. |
- Bengtsson, J., et al.
(författare)
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Hybrid Modelling of Homogeneous Charge Compression Ignition (HCCI) Engine Dynamics—A Survey
- 2007
-
Ingår i: International Journal of Control. - : Informa UK Limited. - 0020-7179 .- 1366-5820. ; 80:11, s. 1814-1848
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Tidskriftsartikel (refereegranskat)abstract
- The Homogeneous charge compression ignition (HCCI) principle holds promise to increase efficiency and to reduce emissions from internal combustion engines. As HCCI combustion lacks direct ignition timing control and auto-ignition depends on the operating condition, control of auto-ignition is necessary. Since auto-ignition of a homogeneous mixture is very sensitive to operating conditions, a fast combustion phasing control is necessary for reliable operation. To this purpose, HCCI modelling and model-based control with experimental validation were studied. A six-cylinder heavy-duty HCCI engine was controlled on a cycle-to-cycle basis in real time using a variety of sensors, actuators and control structures for control of the HCCI combustion in comparison. Combustion phasing control based on ion current was compared to feedback control based on cylinder pressure. With several actuators for controlling HCCI engines suggested, two actuators were compared, dual fuel and variable valve actuation (VVA). Model-based control synthesis requiring dynamic models of low complexity and HCCI combustion models were estimated by system identification and by physical modelling the physical models aiming at describing the major thermodynamic and chemical interactions in the course of an engine stroke and their influence on combustion phasing. The models identified by system identification were used to design model-predictive control (MPC) with several desirable features and today applicable to relatively fast systems, the MPC control results being compared to PID control results. Both control of the combustion phasing and control of load-torque with simultaneous minimization of the fuel consumption and emissions, while satisfying the constraints on cylinder pressure, were included.
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| 9. |
- Bengtsson, Johan, et al.
(författare)
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Model Predictive Control of Homogeneous Charge Compression Ignition (HCCI) Engine Dynamics
- 2006
-
Ingår i: 2006 IEEE Conference on Computer Aided Control System Design, 2006 IEEE International Conference on Control Applications, 2006 IEEE International Symposium on Intelligent Control. ; , s. 1675-1680
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Konferensbidrag (refereegranskat)abstract
- The Homogeneous Charge Compression Ignition ({HCCI}) combustion principle lacks direct ignition timing control, instead the auto-ignition depends on the operating condition and fast combustion phasing control is necessary for reliable operation. A six-cylinder heavy-duty HCCI engine was controlled on a cycle-to-cycle basis in real time using a variety of sensors, actuators and control structures for control of the {HCCI} combustion in comparison. Combustion phasing control based on ion current was compared to feedback control based on cylinder pressure. Two actuators were compared, dual fuel and Variable Valve Actuation (VVA). Model-based control synthesis requiring dynamic models of low complexity and HCCI combustion models were estimated by system identification and by physical modeling. The models identified by system identification were used to design model-predictive control (MPC) with several desirable features and today applicable to relatively fast systems. Both control of the combustion phasing and control of load-torque with simultaneous minimization of the fuel consumption and emissions were included.
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| 10. |
- Bengtsson, Johan, et al.
(författare)
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Multi-Output Control of a Heavy Duty HCCI Engine Using Variable Valve Actuation and Model Predictive Control
- 2006
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Ingår i: 2006 SAE World Congress. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International.
-
Konferensbidrag (refereegranskat)abstract
- Autoignition of a homogeneous mixture is very sensitive to operating conditions, therefore fast control is necessary for reliable operation. There exists several means to control the combustion phasing of an Homogeneous Charge Compression Ignition (HCCI) engine, but most of the presented controlled HCCI result has been performed with single-input single-output controllers. In order to fully operate an HCCI engine several output variables need to be controlled simultaneously, for example, load, combustion phasing, cylinder pressure and emissions. As these output variables have an effect on each other, the controller should be of a structure which includes the cross-couplings between the output variables. A Model Predictive Control (MPC) controller is proposed as a solution to the problem of load-torque control with simultaneous minimization of the fuel consumption and emissions, while satisfying the constraints on cylinder pressure. One of the major motivations for using MPC is that it explicitly takes the constraints into account. When operating an HCCI engine there are several contraints present, for example on the cylinder pressure and on the emissions. A drawback of MPC is the potentially large on-line computational effort, which has historically limited its application to relative slow and/or small applications. Today, MPC can be applied in relative fast systems, and we will demonstrate that it can be used for control of HCCI engine dynamics on a cycle-to-cycle basis. As feedback signal of the combustion phasing, the crank angle for 50% burned, based on cylinder pressure, is used. In the control design of the MPC controllers (one for each cylinder), dynamic models obtained by system identification were used. This paper presents cycle-to-cycle cylinder individual control results from a six-cylinder HCCI engine using a Variable Valve Actuation (VVA) system and MPC controllers.
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| 11. |
- Bengtsson, Johan, et al.
(författare)
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System Identification of Homogenous Charge Compression Ignition (HCCI) Engine Dynamics
- 2004
-
Ingår i: Advances in Automotive Control. - 0080442501 ; 37:22, s. 37-37
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Konferensbidrag (refereegranskat)abstract
- Homogeneous Charge Compression Ignition (HCCI) combustion lacksdirect ignition timing control, instead the auto ignition depends on the operatingcondition. Since auto ignition of a homogeneous mixture is very sensitive tooperating condition a fast combustion timing control is necessary for reliableoperation, the ignition timing control design requiring appropriate modelsand system output variables for its feedback design. This paper demonstratesthe use of system modeling and identification as a means to find modelsrelevant to the engine control. The identification methods used were varioussubspace-based methods. An LQG controller was designed based on the estimatedmodels and tested on a six-cylinder heavy duty engine running in HCCI operation.
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| 12. |
- Benvenuti, Luca, et al.
(författare)
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Automotive Control
- 2009. - 1
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Ingår i: Handbook of Hybrid Systems and Control, Theory – Tools – Applications. - 9780521765053 ; , s. 439-470
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Bokkapitel (refereegranskat)abstract
- utomotive systems offer a rich opportunity for hybrid models, controls, and tools. Beyond the traditional use of hybrid models for representing the behavior of the composition of discrete controller and continuous plants, automotive mechanical systems exhibit hybrid behavior as demonstrated in this chapter. In addition, hybrid systems can be used to capture system specifications at the highest level of abstraction and to model implementation architectures thus enabling a rich design space exploration.
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| 13. |
- Blomberg, Hans, et al.
(författare)
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Poor chest compression quality with mechanical compressions in simulated cardiopulmonary resuscitation : A randomized, cross-over manikin study
- 2011
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Ingår i: Resuscitation. - : Elsevier BV. - 0300-9572 .- 1873-1570. ; 82:10, s. 1332-1337
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Mechanical chest compression devices are being implemented as an aid in cardiopulmonary resuscitation (CPR), despite lack of evidence of improved outcome. This manikin study evaluates the CPR-performance of ambulance crews, who had a mechanical chest compression device implemented in their routine clinical practice 8 months previously. The objectives were to evaluate time to first defibrillation, no-flow time, and estimate the quality of compressions. Methods: The performance of 21 ambulance crews (ambulance nurse and emergency medical technician) with the authorization to perform advanced life support was studied in an experimental, randomized cross-over study in a manikin setup. Each crew performed two identical CPR scenarios, with and without the aid of the mechanical compression device LUCAS. A computerized manikin was used for data sampling. Results: There were no substantial differences in time to first defibrillation or no-flow time until first defibrillation. However, the fraction of adequate compressions in relation to total compressions was remarkably low in LUCAS-CPR (58%) compared to manual CPR (88%) (95% confidence interval for the difference: 13-50%). Only 12 out of the 21 ambulance crews (57%) applied the mandatory stabilization strap on the LUCAS device. Conclusions: The use of a mechanical compression aid was not associated with substantial differences in time to first defibrillation or no-flow time in the early phase of CPR. However, constant but poor chest compressions due to failure in recognizing and correcting a malposition of the device may counteract a potential benefit of mechanical chest compressions.
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| 14. |
- Bucin, Dragan, et al.
(författare)
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Heart transplantation across the antibodies against HLA and ABO
- 2006
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Ingår i: Transplant International. - : Frontiers Media SA. - 1432-2277 .- 0934-0874. ; 19:3, s. 239-244
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Tidskriftsartikel (refereegranskat)abstract
- We have intentionally performed heart transplantation in a 5-year-old child, despite the most unfavourable risk factors for patient survival; the presence of high level of antibodies against donor's human leucocyte antigen (HLA) class I/II and blood group antigens. Pretransplant treatment by mycophenolate mofetil, prednisolone, tacrolimus, intravenous immunoglobulin, rituximab, protein-A immunoadsorption (IA) and plasma exchange reduced antibody titres against the donor's lymphocytes from 128 to 16 and against the donor's blood group antigen from 256 to 0. The patient was urgently transplanted with a heart from an ABO incompatible donor (A(1) to O). A standard triple-drug immunosuppressive protocol was used. No hyperacute rejection was seen. Antibodies against the donor's HLA antigens remained at a low level despite three acute rejections. Rising anti-A(1) blood group antibodies preceded the second rejection and were reduced by two blood group-specific IAs and remained at a low level. The patient is doing well despite the persistence of donor-reactive antibodies.
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| 15. |
- Ekholm, Kent, et al.
(författare)
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Ethanol-Diesel Fumigation in a Multi-Cylinder Engine
- 2008
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Ingår i: SAE technical paper 2008-01-0033.
-
Konferensbidrag (refereegranskat)abstract
- Fumigation was studied in a 12 L six-cylinder heavy-duty engine. Port-injected ethanol was ignited with a small amount of diesel injected into the cylinder. The setup left much freedom for influencing the combustion process, and the aim of this study was to find operation modes that result in a combustion resembling that of a homogeneous charge compression ignition (HCCI) engine with high efficiency and low NOx emissions. Igniting the ethanol-air mixture using direct-injected diesel has attractive properties compared to traditional HCCI operation where the ethanol is ignited by pressure alone. No preheating of the mixture is required, and the amount of diesel injected can be used to control the heat release rate. The two fuel injection systems provide a larger flexibility in extending the HCCI operating range to low and high loads. It was shown that cylinder-to-cylinder variations present a considerable challenge for this type of combustion. By using closed-loop cylinder-individual control based on incylinder pressure sensors, combustion was successfully harmonized between the cylinders. Successful fumigation operation was verified up to 18.4 bar BMEP at a fixed engine speed of 1450 rpm. Two load points (4.6 bar BMEP and 9.2 bar BMEP) were studied in detail. Different diesel injection timings, diesel ratios, and EGR rates were investigated, and comparisons were drawn to pure diesel operation of the same engine. At medium load (9.2 bar BMEP), it was possible to obtain a stable HCCI-like combustion with low NOx emissions (0.1 g/kWh), reasonably high brake efficiency (37 %), and low pressure derivatives (5 bar/CAD). High load operation (18.4 bar BMEP) resulted in low pressure derivatives (5.5 bar/CAD), acceptable brake efficency (36 %), and relatively low NOx emissions (0.34 g/kWh).
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| 16. |
- Ekholm, Kent, et al.
(författare)
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Ethanol-Diesel Fumigation in a Multi-Cylinder Engine
- 2009
-
Ingår i: SAE International Journal of Fuels and Lubricants. - 1946-3952. ; 1:1, s. 26-36
-
Tidskriftsartikel (refereegranskat)abstract
- Fumigation was studied in a 12 L six-cylinder heavy-duty engine. Port-injected ethanol was ignited with a small amount of diesel injected into the cylinder. The setup left much freedom for influencing the combustion process, and the aim of this study was to find operation modes that result in a combustion resembling that of a homogeneous charge compression ignition (HCCI) engine with high efficiency and low NOx emissions. Igniting the ethanol-air mixture using direct-injected diesel has attractive properties compared to traditional HCCI operation where the ethanol is ignited by pressure alone. No preheating of the mixture is required, and the amount of diesel injected can be used to control the heat release rate. The two fuel injection systems provide a larger flexibility in extending the HCCI operating range to low and high loads. It was shown that cylinder-to-cylinder variations present a challenge for this type of combustion. By using closed-loop cylinder-individual control of pressure derivatives and IMEP with the amounts of fuels injected, combustion was successfully harmonized between the cylinders. Successful fumigation operation was verified up to 18.4 bar BMEP at a fixed engine speed of 1450 rpm. Two load points (4.6 bar BMEP and 9.2 bar BMEP) were studied in detail. Different diesel injection timings, diesel ratios, and EGR rates were investigated, and comparisons were drawn to pure diesel operation of the same engine. At medium load (9.2 bar BMEP), it was possible to obtain a stable HCCI-like combustion with low NOx emissions (0.1 g/kWh), reasonably high brake efficiency (38 %), and low pressure derivatives (5 bar/CAD). High load operation (18.4 bar BMEP) resulted in low pressure derivatives (5.5 bar/CAD), acceptable brake efficency (38 %), and relatively low NOx emissions (0.34 g/kWh).
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| 17. |
- Esberg, Anders, et al.
(författare)
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43-Year Temporal Trends in Immune Response to Oral Bacteria in a Swedish Population
- 2020
-
Ingår i: Pathogens. - Basel : MDPI. - 2076-0817. ; 9:7
-
Tidskriftsartikel (refereegranskat)abstract
- Bacteria colonizing the mouth induce an adaptive immune response with the systemic and local presence of species or strain-specific immunoglobulins. Few studies have addressed global antibody patterns for oral bacteria or potential population time trends. We assessed these aspects in relation to a panel of oral bacteria. Using multiplex immunoblotting, IgG levels for 26 oral bacterial species (54 strains) were determined in 888 plasma samples from 30-year-old early pregnant women (n = 516) and 50-year-old men and women (n = 372) collected between 1976 and 2018. Inter-species correlations were found and age-dependent profiles and levels of immune responses to oral bacteria confirmed. We found temporal trends in the global and single-species antibody responses, but this was age-specific with both inclining and declining shifts. Prominent shifts in the younger group increased IgG towards health-associated Streptococcus salivarius and Streptococcus sanguinis, and in the older group towards disease-associated Aggregatibacter actinomycetemcomitans, Filifactor alocis, and Streptococcus mutans, among others. We concluded that temporal shifts occurred from 1976 to 2018, which may reflect improved oral health (more remaining teeth) and altered lifestyle habits, but this needs to be evaluated in observational studies considering more aspects.
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| 18. |
- Henningsson, Maria, et al.
(författare)
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Closed-Loop Control of Combustion Phasing in an HCCI Engine Using VVA and Variable EGR
- 2007. - 10
-
Ingår i: 5th IFAC Symposium on Advances in Automotive Control. ; 40, s. 501-506
-
Konferensbidrag (refereegranskat)abstract
- A homogeneous charge compression ignition (HCCI) engine requires closed-loop control of combustion phasing for reliable operation. Variable valve actuation (VVA) has previously been shown to enable cycle-to-cycle, cylinder-individual control with high precision, but suffers from a narrow operating range. Adding variable exhaust gas recirculation (EGR) to the closed-loop control structure can extend the operating range. A mid-ranging control structure is presented here for combined VVA and EGR actuations in a multi-cylinder engine. The control structure is simple to implement and preserves the fast, cylinder-individual, and precise actuation of the VVA system while extending the operating range. Experimental results verify the performance of the control structure.
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| 19. |
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| 20. |
- Johansson, Bengt, et al.
(författare)
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A Physical Two-Zone NOx Model Intended for Embedded Implementation
- 2009
-
Ingår i: SAE Technical Papers. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0148-7191.
-
Konferensbidrag (refereegranskat)abstract
- This paper offers a two-zone NOx model suitable for vehicle on-board, on-line implementation. Similar NOx modeling attempts have previously been undertaken. The hereby suggested method does however offer clear and important benefits over the previously methods, utilizing a significantly different method to handle temperature calculations within the (two) different zones avoiding iterative computation. The new method significantly improves calculation speed and, most important of all, reduces implementation complexity while still maintaining reasonable accuracy and the physical interpretation of earlier suggested methods. The equations commonly used to compute NOx emissions is also rewritten in order to suit a two-zone NOx model. An algorithm which can be used to compute NOx emissions is presented and the intended contribution of the paper is a NOx model, implementation feasible for an embedded system, e.g. embedded processor or embedded electronic hardware (FPGA). For that purpose parts of the algorithm can be pre-computed and stored in tables allowing significant acceleration of the computation.
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| 21. |
- Johansson, Björn, et al.
(författare)
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Distributed resource allocation strategies for achieving quality of service in server clusters
- 2006
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Ingår i: PROCEEDINGS OF THE 45TH IEEE CONFERENCE ON DECISION AND CONTROL. ; , s. 1990-1995
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Konferensbidrag (refereegranskat)abstract
- We investigate the resource allocation problem for large-scale server clusters with quality-of-service objectives, where key functions are decentralized. Specifically, the optimal service selection is posed as a discrete utility maximization problem that reflects management objectives and resource constraints. We develop an efficient centralized algorithm that solves this problem, and we propose three suboptimal schemes that operate with local information. The performance of the suboptimal schemes is evaluated in simulations, both under idealized conditions and in a full-scale system simulator.
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| 22. |
- Johansson, Christer, et al.
(författare)
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Extern redovisning
- 2009
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- Extern redovisning behandlar allt från redovisningens grunder, sambandet mellan de olika finansiella rapporterna till beräkning av finansiella nycketal för interna och externa intressenter. I denna tredje upplaga har en omfattande revidering skett mot bakgrund av förändringar i lagar och regler. Dessutom har en större pedagogisk omstrukturering gjorts. I alla företag sker mängder av aktiviteter och dagligen fattas ett stort antal viktiga beslut. Bokens avsikt är att beskriva hur redovisningen kan tillhandahålla underlag för dessa beslut. Därigenom blir redovisning en viktig faktor för tillväxt och utveckling i hela samhällsekonomin.
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| 23. |
- Johansson, Christer, et al.
(författare)
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Extern redovisning
- 2021
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Bok (övrigt vetenskapligt/konstnärligt)
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| 24. |
- Johansson, Christer, 1964, et al.
(författare)
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Externredovisning
- 2007
-
Bok (övrigt vetenskapligt/konstnärligt)
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| 25. |
- Johansson, Christer, et al.
(författare)
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Externredovisning
- 2013
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Bok (övrigt vetenskapligt/konstnärligt)
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| 26. |
- Johansson, Jakob, et al.
(författare)
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Prehospital Trauma Life Support (PHTLS) training of ambulance caregivers and impact on survival of trauma victims
- 2012
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Ingår i: Resuscitation. - : Elsevier BV. - 0300-9572 .- 1873-1570. ; 83:10, s. 1259-1264
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND:The Prehospital Trauma Life Support (PHTLS) course has been widely implemented and approximately half a million prehospital caregivers in over 50 countries have taken this course. Still, the effect on injury outcome remains to be established. The objective of this study was to investigate the association between PHTLS training of ambulance crew members and the mortality in trauma patients.METHODS:A population-based observational study of 2830 injured patients, who either died or were hospitalized for more than 24h, was performed during gradual implementation of PHTLS in Uppsala County in Sweden between 1998 and 2004. Prehospital patient records were linked to hospital-discharge records, cause-of-death records, and information on PHTLS training and the educational level of ambulance crews. The main outcome measure was death, on scene or in hospital.RESULTS:Adjusting for multiple potential confounders, PHTLS training appeared to be associated with a reduction in mortality, but the precision of this estimate was poor (odds ratio, 0.71; 95% confidence interval, 0.42-1.19). The mortality risk was 4.7% (36/763) without PHTLS training and 4.5% (94/2067) with PHTLS training. The predicted absolute risk reduction is estimated to correspond to 0.5 lives saved annually per 100,000 population with PHTLS fully implemented.CONCLUSIONS:PHTLS training of ambulance crew members may be associated with reduced mortality in trauma patients, but the precision in this estimate was low due to the overall low mortality. While there may be a relative risk reduction, the predicted absolute risk reduction in this population was low.
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| 27. |
- Johansson, Katarina, 1980-
(författare)
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Thermally cured coil-coatings utilizing novel resins and fatty acid methyl esters as reactive diluents
- 2008
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Solvent-borne thermally cured coil-coating resins contain large amounts of volatile organic solvents in order to obtain suitable flow for film application. This work describes how the expensive and environmental hazardous volatile organic solvent content of a solvent-borne thermally cured polyester/melamine coil-coating system can be reduced by introduction of fatty acid methyl esters (FAMEs) as reactive diluents and modification of the polyester binder resin. The evaluated reactive diluents, two rape seed methyl esters (RMEs), two linseed oil methyl esters (LMEs), and a tall oil methyl ester (TOME) have been evaluated both in a fully formulated clear-coat system and via model studies. Viscosity measurements of wet paint mixtures showed that formulations with hyperbranched polyester binder hold lower viscosity than conventional polyester binder resins and that FAME works as a diluent. Fully formulated clear-coats were cured under simulated industrial coil-coating cure conditions and in a convection oven at lower temperatures respectively. FAME increases the mobility of the system enhancing the film formation process. Free-standing clear-coat films were analyzed with Raman, carbon-14 dating, extraction, dynamic mechanical analysis, and visual observation. Incorporation of FAME could not be confirmed by Raman analysis. However, carbon-14 dating indicated the presence of FAME that could not be extracted from the films. The mechanical properties of the films were also affected by the addition of FAMEs, oven temperature, choice of co-solvent, and flash-off period. Conventional film characterization tests on substrate supported coatings indicated that binder resin structure and cure conditions affect the final film properties. Model studies were performed to clarify how FAME can chemically react through transesterification with the hydroxyl-groups of the polyester. The transesterification reaction between different FAMEs and primary alcohols with and without tertiary hydrogen was monitored with 1H-NMR and real time IR. Evaporation and side reactions, e.g. alkene reactions, are competing factors to the transesterification reaction. The study showed that fatty acid structure, reaction time, and temperature affect the transesterification conversion, degree of side reactions, and choice of catalyst. A pigmented fully formulated polyester/melamine formulation with a reactive diluent was cured at full scale in an industrial coil-coating production facility. Evaluation of the final film properties showed that the coating fulfills the specification of conventional polyester/melamine coil-coating systems.
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| 28. |
- Johansson, Ola, et al.
(författare)
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Model Predictive Control for Scheduling and Routing in a Solid Waste Management System
- 2008
-
Ingår i: IFAC Proceedings Volumes (IFAC-PapersOnline). - 2405-8963. ; 17:1, s. 4481-4486
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Tidskriftsartikel (refereegranskat)abstract
- Solid waste collection and hauling account for the greater part of the total cost in modern solid waste management systems. In a recent initiative, 3,300 Swedish recycling containers have been fitted with level sensors and wireless communication equipment thereby giving waste collection operators access to real-time information on the status of each container. In a previous study (Johansson, 2006), analytical modeling and discrete-event simulation have been used to evaluate different scheduling and routing policies utilizing the real-time data, and it has been shown that dynamic scheduling and routing policies exist that have lower operating costs, shorter collection and hauling distances, and reduced labor hours compared to the static policy with fixed routes and pre-determined pick-up frequencies employed by many waste collection operators today. This study aims at further refining the scheduling and routing policies by employing a model predictive control (MPC) framework on the system. In brief, the MPC controller should minimize an objective cost function consisting of fixed and variable collection and hauling costs for a fixed future horizon by calculating a sequence of tactical scheduling and routing decisions that satisfies system constraints using a receding horizon strategy.
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| 29. |
- Johansson, Rolf, et al.
(författare)
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Bokslutet från början
- 2008
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- Bokslutet från början är en kombinerad fakta- och övningsbok som är en direkt fortsättning på grundboken i bokföring, Bokföring från början. I denna bok fördjupas kunskaperna. Steg för steg behandlas de olika områden man måste behärska för att kunna upprätta ett fullständigt bokslut med årsredovisning i enlighet med årsredovisningslagens krav.
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| 30. |
- Johansson, Rolf, et al.
(författare)
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Bokslutet från början
- 2013
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Bok (populärvet., debatt m.m.)abstract
- Bokslutet från början är en kombinerad fakta- och övningsbok. Steg för steg behandlas de olika områden man måste behärska för att kunna upprätta ett fullständigt bokslut med årsredovisning i enlighet med årsredovisningslagens krav.
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| 31. |
- Johansson, Rolf, et al.
(författare)
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Bokslutet från början
- 2011
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Bok (populärvet., debatt m.m.)abstract
- Bokslutet från början är en kombinerad fakta- och övningsbok som är en direkt fortsättning på grundboken i bokföring, Bokföring från början. I denna bok fördjupas kunskaperna. Steg för steg behandlas de olika områden man måste behärska för att kunna upprätta ett fullständigt bokslut med årsredovisning i enlighet med årsredovisningslagens krav. För varje moment finns ett stort antal övningar.
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| 32. |
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| 33. |
- Johansson, Rolf, et al.
(författare)
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Bokslutet från början: Fakta och övningsbok
- 2020. - 12
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Bok (populärvet., debatt m.m.)abstract
- Bokslutet från början är en kombinerad fakta- och övningsbok som är en direkt fortsättning på grundboken i bokföring, Bokföring från början. I denna bok fördjupas kunskaperna. Steg för steg behandlas de olika områden man måste behärska för att kunna upprätta ett fullständigt bokslut med årsredovisning i enlighet med årsredovisningslagens krav. För varje moment finns ett stort antal övningar.
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| 34. |
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| 35. |
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| 36. |
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| 37. |
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| 38. |
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| 39. |
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| 40. |
- Marton, Jan, 1964, et al.
(författare)
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Externredovisning
- 2004
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Bok (övrigt vetenskapligt/konstnärligt)
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| 41. |
- Olsson, Jan-Ola, et al.
(författare)
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Closed-loop System Identification of an HCCI Engine
- 2004
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Ingår i: Advances in Automotive Control. - 0080442501 ; 37:22, s. 239-244
-
Konferensbidrag (refereegranskat)abstract
- Homogeneous Charge Compression Ignition (HCCI) is a promising but challenging combustion engine concept. The potential for good fuel economy and low emissions is high but the transient performance required for automotive applications presents a few problems still to be solved. The focus of this work is identification of the process dynamics. An ARX type model is fitted to input-output data. A method applicable under closed-loop control is suggested and demonstrated. The resulting models are evaluated in terms of the repeatability of model characteristics, prediction accuracy, residual characteristics and comparison to spectral models is made.
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| 42. |
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| 43. |
- Pfeiffer, Roland, et al.
(författare)
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System Identification and LQG Control of Variable-Compression HCCI Engine Dynamics
- 2004
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Ingår i: Proceedings of the 2004 IEEE International Conference on Control Applications.. - 1085-1992. - 0780386337 ; 2, s. 1442-1447
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Konferensbidrag (refereegranskat)abstract
- The Homogenous Charge Compression Ignition (HCCI) combustion engine has potential to replace the spark ignition and compression ignition engines of today. One of the main problems in making the engine commercially attractive is the lack of direct means of controlling the ignition phasing. In this paper, we investigate the potential of inlet air temperature as a means to ignition actuation. This article describes a method for system identification of the HCCI process, and development of an effective LQG regulator for the combustion process, Matlab and Simulink being used in computations and simulations.
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| 44. |
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| 45. |
- Strandh, Petter, et al.
(författare)
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Cycle-to-Cycle Control of a Dual-Fuel HCCI Engine
- 2004
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Ingår i: SAE Paper 2004-01-0941. - 0148-7191. - 0768013550 ; SP-1819
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Konferensbidrag (refereegranskat)abstract
- A known problem of the HCCI engine is its lack of direct control andits requirements of feedback control. Today there exists severaldifferent means to control an HCCI engine, such as dual fuels,variable valve actuation, inlet temperature and compression ratio.Independent of actuation method a sensor is needed. In this paper weperform closed-loop control based on two different sensors, pressureand ion current sensor. Results showing that they give similar controlperformance within their operating range are presented.Also a comparison of two methods of designing HCCI timing controller,manual tuning and model based design is presented. A PIDcontroller is used as an example of a manually tuned controller. ALinear Quadratic Gaussian controller exemplifies model basedcontroller design. The models used in the design were estimated usingsystem identification methods.The system used in this paper performs control on cycle-to-cyclebasis. This leads to fast and robust control. Dual fuels withdifferent octane numbers were used to control the combustion timing.The engine was a 12 liter 6 cylinder heavy-duty diesel engine modifiedwith a port fuel injection system which has dual fuels connected.
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| 46. |
- Strandh, Petter, et al.
(författare)
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Ion Current Sensing for HCCI Combustion Feedback
- 2003
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Ingår i: SAE Technical Papers. - 0148-7191. ; :2003-01-3216
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Konferensbidrag (refereegranskat)abstract
- Measurement of ion current signal from HCCI combustionwas performed. The aim of the work was to investigateif a measurable ion current signal exists and if it is possible to obtain useful information about the combustion process. Furthermore, influence of mixture quality in termsof air/fuel ratio and EGR on the ion current signal wasstudied. A conventional spark plug was used as ionizationsensor. A DC voltage (85 Volt) was applied acrossthe electrode gap. By measuring the current through thegap the state of the gas can be probed. A comparisonbetween measured pressure and ion current signal wasperformed, and dynamic models were estimated by usingsystem identification methods.The study shows that an ion current signal can be obtainedfrom HCCI combustion and that the signal levelis very sensitive to the fuel/air equivalence ratio. Themost important result from this study is that the ion current signal proved to be an excellent indicator of the actual combustion timing which is crucial piece of information for HCCI control.
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| 47. |
- Strandh, Petter, et al.
(författare)
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Variable Valve Actuation for Timing Control of a Homogeneous Charge Compression Ignition Engine
- 2005
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Ingår i: SAE Technical Papers 2005-01-0147. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0148-7191.
-
Konferensbidrag (refereegranskat)abstract
- Autoignition of a homogeneous mixture is very sensitiveto operating conditions. Therefore fast combustion phasingcontrol is necessary for reliable operation. There areseveral means to control the combustion phasing of a Homogeneous Charge Compression Ignition (HCCI) engine.This paper presents cycle-to-cycle cylinder individual controlresults from a six-cylinder HCCI engine using a VariableValve Actuation (VVA) system. As feedback signal,the crank angle for 50% burned, based on cylinder pressure,is used. Three control structures are evaluated,Model Predictive Control (MPC), Linear Quadratic Gaussiancontrol (LQG) and PID control. In the control designof the MPC and LQG controller, dynamic models obtainedby system identication were used. Successful experimentswere performed on a port-injected six-cylinderheavy-duty Diesel engine operating in HCCI mode.
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| 48. |
- Troeng, Olof, et al.
(författare)
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Control Problems at the European Spallation Source
- 2016
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Ingår i: Abstracts of Reglermöte 2016.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A background on the Europan Spallation Source is given, and our work on three control problems important for the design of its linear accelerator are presented.
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| 49. |
- Tunestål, Per, et al.
(författare)
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Closed-Loop Combustion Control of HCCI Engines
- 2003
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Ingår i: Nonlinear and Hybrid Systems in Automotive Control. ; , s. 321-334
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- The HCCI engine, with its excellent potential for high efficiency and low NOx emissions, is investigated from a control perspective. Combustion timing, i.e., where in the thermodynamic cycle combustion takes place, is identified as the most challenging problem with HCCI engine control. A number of different means for controlling combustion timing are suggested, and results using a dual-fuel solution are presented. This solution uses two fuels with different ignition characteristics to control the time of autoignition. Cylinder pressure measurement is suggested for feedback of combustion timing. A simple net-heat release algorithm is applied to the measurements, and the crank angle of 50% burnt is extracted. Open-loop instability is detected in some high-load regions of the operating range. This phenomenon is explained by positive feedback between the cylinder wall heating and ignition timing processes. Closed-loop performance is hampered by time delays and model uncertainties. This problem is particularly pronounced at operating points that are open-loop unstable.
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| 50. |
- Widd, Anders, et al.
(författare)
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Investigating Mode Switch from SI to HCCI using Early Intake Valve Closing and Negative Valve Overlap
- 2011
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Ingår i: SAE technical paper series. - 0148-7191.
-
Tidskriftsartikel (refereegranskat)abstract
- This study investigates mode switching from spark ignited operation with early intake valve closing to residual gas enhanced HCCI using negative valve overlap on a port-fuel injected light-duty diesel engine. A mode switch is demonstrated at 3.5 bar IMEPnet and 1500 rpm. Valve timings and fuel amount have to be selected carefully prior to the mode switch. During mode transition, IMEPnet deviates by up to 0.5 bar from the set point. The time required to return to the set point as well as the transient behavior of the engine load varies depending on which control structure that is used. Both a model-based controller and a PI control approach were implemented and evaluated in experiments. The controllers were active in HCCI mode. The model-based controller achieved a smoother transition and while using it, the transition could be accomplished within three engine cycles. The initial deviation in load is unacceptable but can most likely be improved with a predictive mode transition model compared to empirically selected mode transition parameters. Changing the fuel injection method to direct injection instead of port injection is another possible improvement.
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