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Real-time performance of DAE and ODE based estimators evaluated on a diesel engine

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Science China(Information Sciences) 2018年第7期61卷 27-39页

作者： Erik H?CKERDAL Erik FRISK lars.eriksson Scania CV AB Vehicular Systems Link?ping University

Computation and sampling time requirements for real-time implementation of observers is studied. A common procedure for state estimation and observer design is to have a system model in continuous time that is converted to sampled time with Euler forward method and then the observer is designed and implemented in sampled time in the real time system. When considering state estimation in real time control systems for production there are often limited computational resources. This becomes especially apparent when designing observers for stiff systems since the discretized implementation requires small step lengths to ensure stability. One way to reduce the computational burden, is to reduce the model stiffness by approximating the fast dynamics with instantaneous relations, transforming an ordinary differential equations(ODE)model into a differential algebraic equation(DAE) model. Performance and sampling frequency limitations for extended Kalman filter(EKF)'s based on both the original ODE model and the reduced DAE model are here analyzed and compared for an industrial system. Furthermore, the effect of using backward Euler instead of forward Euler when discretizing the continuous time model is also analyzed. The ideas are evaluated using measurement data from a diesel engine. The engine is equipped with throttle, exhaust gas recirculation(EGR), and variable geometry turbines(VGT) and the stiff model dynamics arise as a consequence of the throttle between two control volumes in the air intake system. The process of simplifying and modifying the stiff ODE model to a DAE model is also discussed. The analysis of the computational effort shows that even though the ODE, for each time-update, is less computationally demanding than the resulting DAE, an EKF based on the DAE model achieves better estimation performance than one based on the ODE with less computational effort. The main gain with the DAE based EKF is that it allows increased step lengths without degrading the

关键词： estimation learning DAE ODE EKF observability real-time

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Editorial

Control Theory and Technology 2019年第2期17卷 119-120页

作者： Tielong SHEN lars.eriksson Per TUNESTAL Sophia University Japan Linkoping University Sweden Lund University Sweden

Control theory is the field that is deeply connected with *** control a physical process or a dynarnica!system,the control law,so-called control algorithm,is usually deduced in mathematical *** leads a lot of control theorist to work on"pure control theory"and leave from the physical *** gap between control theory and practice is sometimes pointed out by the engineers,since a lot of advaneed control methods provided by the research comm unity of control theory cannot be directly implemented for solving many in dustrial *** problem plays the role of bridge between the theoretical research and industrial ***,a benchmark problem is proposed by academic community or jointly with industrial community to highlight challengi ng issues in a focused problem with comm on interested practical backgro *** control problem,many technical committees of international federation of automatic control(IFAC)proposed a lot of benchmark problems in the *** benchmark problems attracted attention from both of theorist and control practitioners,especially younger researchers and students,and pushed control theorist to challenge practical problem and innovation in industrial control *** special issue focused on the benchmark problems in automotive system control which are mainly organized by I FAC technical committee and the related community such as the society of instrument and control engineers(SICE),Japan.

关键词： Japan SICE IFAC

Surface integral analogy approaches for predicting noise from 3D high-lift low-noise wings

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Acta Mechanica Sinica 2014年第3期30卷 326-338页

作者： Hua-Dong Yao lars Davidson lars-Erik eriksson Shia-Hui Peng Olof Grundestam Peter E.Eliasson Department of Applied Mechanics Chalmers University of Technology Department of Aeronautics and Systems Technology Swedish Defence Research Agency (FOI)

Three surface integral approaches of the acoustic analogies are studied to predict the noise from three concep- tual configurations of three-dimensional high-lift low-noise wings. The approaches refer to the Kirchhoff method, the Ffowcs Williams and Hawkings （FW-H） method of the permeable integral surface and the Curle method that is known as a special case of the FW-H method. The first two approaches are used to compute the noise generated by the core flow region where the energetic structures exist. The last approach is adopted to predict the noise specially from the pressure perturbation on the wall. A new way to con- struct the integral surface that encloses the core region is proposed for the first two methods. Considering the local properties of the flow around the complex object-the actual wing with high-lift devices-the integral surface based on the vorticity is constructed to follow the flow structures. The surface location is discussed for the Kirchhoff method and the FW-H method because a common surface is used for them. The noise from the core flow region is studied on the basis of the dependent integral quantities, which are indicated by the Kirchhoff formulation and by the FW-H formulation. The role of each wall component on noise contribution is analyzed using the Curle formulation. Effects of the volume integral terms of Lighthill＇s stress tensors on the noise pre-diction are then evaluated by comparing the results of the Curle method with the other two methods.

关键词： Aero-acoustics High-lift facilities Surface integral approaches of acoustic analogy

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Real-time energy optimization of HEVs under-connected environment: a benchmark problem and receding horizon-based solution

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Control Theory and Technology 2022年第2期20卷 145-160页

作者： Fuguo Xu Hiroki Tsunogawa Junichi Kako Xiaosong Hu Shengbo Eben Li Tielong Shen lars.eriksson Carlos Guardiola Department of Engineering and Applied Sciences Sophia UniversityTokyo 102-8554Japan Higashi-Fuji Research Center Toyota Motor Corporation.Shizuoka 410-1107Japan The State Key Laboratory of Mechanical Transmissions Chongqing UniversityChongqing 400044China The State Key Laboratory of Automotive Safety and Energy Tsinghua UniversityBeijing 100084China Vehicular Systems Department Electrical EngineeringLinkoping UniversitySE 58183Linkoping.Sweden Departamento de Maquinas y Motores Termicos Universitat Politecnica de Valencia.Camino de Vera s/n46022 ValenciaSpain

In this paper,we propose a benchmark problem for the challengers aiming to energy efficiency control of hybrid electric vehicles(HEVs)on a road with ***,it is assumed that the targeted HEVs are in the connected environment with the obtainment of real-time information of vehicle-to-everything(V2X),including geographic information,vehicle-to-infrastructure(V2I)information and vehicle-to-vehicle(V2V)*** provided simulator consists of an industrial-level HEV model and a traffic scenario database obtained through a commercial traffic simulator,where the running route is generated based on real-world data with slope and intersection *** benchmark problem to be solved is the HEVs powertrain control using traffic information to fulfill fuel economy improvement while satisfying the constraints of driving safety and travel *** show the HEV powertrain characteristics,a case study is given with the speed planning and energy management strategy.

关键词： Powertrain control Connected and automated vehicles Hybrid electric vehicles Vehicle-to-everything

Special focus on learning and real-time optimization of automotive powertrain systems

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Science China(Information Sciences) 2018年第7期61卷 5-5页

作者： Tielong SHEN lars.eriksson Sophia University Linkping University

The control of automotive powertrain systems is challenging for dynamical systems theory and control technology because of the complexity,uncertainty,and stochasticity in the *** mass production of a specified powertrain,normally over millions,a robust calibration of the electrical control unit(ECU)is the first ***,since the operating environment always changes rapidly and the lifetime of a vehicle is longer,the pre-calibrated ECU parameter cannot guarantee the optimality of

关键词： ECU Special focus on learning and real-time optimization of automotive powertrain systems

Comparison of four non-alcoholic fatty liver disease detection scores in a Caucasian population

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World Journal of Hepatology 2020年第4期12卷 149-159页

作者： lars Lind lars Johansson Hakan Ahlstrom Jan W eriksson Anders larsson Ulf Risérus Joel Kullberg Jan Oscarsson Department of Medical Sciences UppsalaUniversityUppsala 75185Sweden Antaros Medical AB BioVenture HubMolndal 43153Sweden Department of Surgical Sciences Uppsala UniversityUppsala 75185Sweden Department of Public Health and Caring Sciences Clinical Nutrition and Metabolism Uppsala UniversityUppsala 75122Sweden Global Medicines Development AstraZenecaMoIndal 43150Sweden

BACKGROUND Non-alcoholic fatty liver disease(NAFLD)is a common disorder,with an estimated prevalence ranging from 20%to 35%in the general *** scores based on easily measurable biochemical and clinical parameters,including the fatty liver index(FLI),hepatic steatosis index(HSI),lipid accumulation product(LAP),and NAFLD liver fat score(LFS),have been developed for the detection of ***,comparative information regarding the efficacy of these scores for predicting NAFLD in population-based samples comprising normal and high-risk individuals is *** To evaluate four NAFLD detection scores in two samples with different NAFLD *** NAFLD screening was performed in a population-based sample of 50-year-old individuals in Uppsala,Sweden[n=310;Prospective investigation of obesity,energy and metabolism(POEM)study]and a high-risk population comprising patients with a body mass index>25 kg/m2 and either high plasma triglycerides(≥1.7 mmol/L)or type 2 diabetes(n=310;EFFECT studies).NAFLD was defined as liver fat>5.5%using magnetic resonance imaging-proton density fat ***,HSI,LAP,and NAFLD LFS were assessed.A logistic regression model was used to evaluate the effectiveness of the different *** The prevalence of NAFLD was 23%in *** showed the highest receiver operating characteristic area under the curve(ROC AUC;0.82)and was significantly better than the LAP score(P=0.005 vs LAP,P=0.08 vs LFS,P=0.12 vs HSI)for detection of *** other three indices performed equally in POEM(0.77-0.78).The prevalence of NAFLD was 74%in EFFECT;LFS performed best(ROC AUC 0.80)in this *** ROC AUC for LFS(0.80)was significantly higher than that for FLI(P=0.0019)and LAP(P=0.0022),but not HSI(P=0.11).We performed a sensitivity analysis with stratification for the two high-risk subgroups(patients with diabetes or hypertriglyceridemia)from the EFFECT *** performed best in patients with *** major differences

关键词： Comparison EFFECT studies Fatty liver Non-alcoholic fatty liver disease Non-invasive indices Screening

Contribution of precursor compounds to the release of per-and polyfluoroalkyl substances(PFASs) from waste water treatment plants(WWTPs)

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Journal of Environmental Sciences 2017年第11期29卷 80-90页

作者： Ulrika eriksson Peter Haglund Anna K?rrman Man-Technology-Environment (MTM) Research Centre School of Science and Technology ?rebro University Department of Chemistry Umea University

Per-and polyfluoroalkyl substances（PFASs） are ubiquitous in sludge and water from waste water treatment plants, as a result of their incorporation in everyday products and industrial processes. In this study, we measured several classes of persistent PFASs,precursors, transformation intermediates, and newly identified PFASs in influent and effluent sewage water and sludge from three municipal waste water treatment plants in Sweden, sampled in 2015. For sludge, samples from 2012 and 2014 were analyzed as *** of precursors in sludge exceeded those of perfluoroalkyl acids and sulfonic acids（PFCAs and PFSAs）, in 2015 the sum of polyfluoroalkyl phosphoric acid esters（PAPs） were 15–20 ng/g dry weight, the sum of fluorotelomer sulfonic acids（FTSAs） was 0.8–1.3 ng/g,and the sum of perfluorooctane sulfonamides and ethanols ranged from non-detected to 3.2 ng/g. Persistent PFSAs and PFCAs were detected at 1.9–3.9 ng/g and 2.4–7.3 ng/g dry weight, respectively. The influence of precursor compounds was further demonstrated by an observed substantial increase for a majority of the persistent PFCAs and PFSAs in water after waste water treatment. Perfluorohexanoic acid（PFHxA）, perfluorooctanoic acid（PFOA）, perfluorohexane sulfonic acid（PFHxS）, and perfluorooctane sulfonic acid（PFOS）had a net mass increase in all WWTPs, with mean values of 83%, 28%, 37% and 58%,respectively. The load of precursors and intermediates in influent water and sludge combined with net mass increase support the hypothesis that degradation of precursor compounds is a significant contributor to PFAS contamination in the environment.

关键词： diPAPs FTSAs Waste water Daily discharge PFCA precursor

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Recruitment in species-rich grasslands: the effects of functional traits and propagule pressure

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Journal of Plant Ecology 2012年第3期5卷 260-269页

作者： MathiasÖster Ove eriksson Department of Botany Stockholm UniversitySE-10691 StockholmSweden

Aims The assembly of plant communities is a complex process which combines impacts from the species pool,dispersal and propagule pressure,niche requirements of colonizing species and the niche structure of the *** theory development has incorporated all these aspects,***‘stochastic niche theory’.We investigated recruitment into a species-rich grassland community,using an experimental approach where we manipulated the trait composition of the community and examined the success of colonizing species entering with various propagule ***,we examined two predictions:(i)colonization success increases with increasing difference between traits of the colonizing species and the trait profile of the community and(ii)colonization success increases with increasing propagule *** The examined communities were species-rich semi-natural grasslands located in southern *** a careful documentation of the composition of the plant communities at the experimental sites,we manipulated the trait profile of species-rich grassland plots based on the plant functional trait specific leaf area(SLA),which is correlated with several key life history *** addition to SLA,seed mass was also used to describe the trait profile of grassland *** of 12 plant species from the regional species pool,varying in SLA and seed mass,were sown into plots using four different levels of propagule *** was examined after 1 *** also planted juvenile‘plug plants’of the same species which allowed us to examine survivorship and growth beyond the seedling *** Findings Overall we found very limited evidence for relationships between the traits of the colonizing species and the trait profile of the community and for recruitment after sowing these relationships were contrary to the *** of plug plants after two seasons of growth was high irrespective of the trait profile of the community,but growth of plug

关键词： assembly rules recruitment limitation seed size semi-natural grassland SLA

HEALTH CONSUMER DIVERSITY AND ITS IMPLICATIONS

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Journal of Systems Science and Systems Engineering 2006年第1期15卷 34-47页

作者： lars EDGREN Group Executive Staff Skne County Council Lund Sweden

Health care consumers no longer want to be passive receivers of treatment and care, they want to be involved. This shift is driven by the new information technology and a ‘social revolution’. Easy access to health information, thanks largely to the Internet, and active health consumer organizations have provided consumers with enabling independent health information. Individual consumers are also more willing to enter into a dialogue, participate and influence decisions concerning their own care. At the same time the consumer role becomes more diverse. Populations in many countries today are culturally, socially, and demographically diverse. Understanding consumer diversity is one of the greatest challenges facing health care providers. There is a risk that the quality of health care provided to consumers can vary depending on the skills of the professionals to tune into the values and preferences of the individual consumer. Health care providers need to listen to and incorporate consumers’ experiences into their health service offerings in new and creative ways. They need to engage in a dialogue with various consumer groups using multiple channels. There is a need for a new business logic, which would structurally help the providers, on an individual basis to deal with more sophisticated health care consumers. This is a review paper and provides a framework and a set of strategies for dealing with health consumer diversity. We draw on three interrelated theories – open systems theory, service management research and the concept of consumer segmentation to understand health care consumers’ attitudes and behaviour, and their expectations.

关键词： Health consumers consumer diversity culturally diverse cultural variation socially diverse systems theory service management consumer segmentation the Internet enabling consumers

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