Peer instruction is a method for activating students during lectures, which has gained a considerable amount of attention in higher education due to claims of dramatic improvement in learning gains. The purpose of this qualitative research study is to investigate what types of discussions engineering students engage in during a peer instruction session and what learning possibilities that are enabled by these different types of discussions. We observed twelve students during six separate and simulated peer instruction sessions and the students were interviewed individually after the sessions.Ananalysis of the data revealed that the students engaged in three qualitatively different types of discussions: affirmative discussions, motivating discussions, and argumentative discussions. We characterize these different types of discussions in terms of the number of alternative answers the students discuss, the extent to which they draw on prior knowledge and experiences, as well as the fundamental difference between an explanation and an argument. A good opportunity for learning is opened up when students are aspiring to find the truth, not simply being satisfied with what they believe to be true. We conclude that students do not always engage in discussions that support their learning in the best way, and we discuss implications for using peer instruction as a teaching method.
Commuting by car from home to work can be very time consuming. We have conducted a study to explore what people are doing, and want to do, while commuting. People use their time in the car on a wide variety of activities with great innovation. There was no unanimous activity that everyone wanted, rather a wide variety of activities were requested. Three different categories of activity were identified which we refer to as mundane, vocational and traffic related. To demonstrate a possible IT service supporting commuters, a prototype based on speech output and a simple input mechanism from a wheel was developed. This service moves sampling of music from the conventional shop into the car. The prototype was informally tested with users, which resulted in a number of improvements. Preliminary user results indicate good functionality, a comprehensive interaction interface.
Elfordon representerar en av de mest lovande vägarna för att nå en fossiloberoende transportsektor och minska koldioxidutsläpp och luftföroreningar. Induktiv laddning av elfordon öppnar för möjligheten att ladda helt automatiskt vilket många tror kan höja elfordonens attraktionskraft och därmed öka försäljningstakten av elfordon. Dock har diskussioner redan satt igång huruvida läckfält vid energiöverföringen kan påverka människor.
Elektromagnetiska fält finns naturligt i vår omgivning, men beroende på typ av fält, frekvens och fältstyrka interagerar de med kroppen på olika sätt. Fält för induktionsladdning ligger i ett intermediärt frekvensområde, det vill säga frekvensmässigt mellan kraftfrekventa och radiofrekventa fält. För kraft- och radiofrekventa fält har en hel del forskning genomförts kring fältens kopplingar till biologiska interaktioner och eventuell negativ hälsopåverkan. Utifrån resultaten har rekommendationer för högsta exponeringsnivåer för fälten tagits fram, även om många av resultaten fortfarande är tvetydiga. För de intermediära fälten saknas i stort sett forskning och därför har rekommendationer för dessa fält i stora delar extrapolerats fram utifrån resultat för kraft- och radiofrekvenser.
Frågorna kring huruvida fält från induktiv laddning kan orsaka hälsoeffekter är därmed fortfarande oklara och därför bör försiktighetsprincipen tillämpas. Vi behöver också koppla samman forskning kring teknikutveckling med forskning som utreder eventuella hälsoeffekter för att höja kunskapsnivån. Därmed kan vi förekomma risken att en debatt blossar upp i samhället där vi står utan svar, vilket skulle kunna påverka elfordonens introduktion i Sverige negativt.
Multilevel Converters are studied for simultaneous_x000D_ use as a DC-motor drive active battery cell balancer._x000D_ The Multilevel Converter (MLC) allows to independently switch_x000D_ ON/OFF each battery cell in a battery pack giving the possibility_x000D_ of non-uniform use of the battery cells. By exploiting this_x000D_ property brake regeneration phases in the drive cycle, the_x000D_ MLC has the possibility to balance both State-of-Charge (SoC)_x000D_ temperature differences between the cells, which are two_x000D_ known causes of battery wear, without even reciprocating the_x000D_ coolant flow inside the pack. The optimal control policy (OP )_x000D_ that takes into consideration both the battery pack temperature_x000D_ SoC dynamics is studied in detail based on the assumption_x000D_ of perfect information of the state the future driving. The_x000D_ results show that OP gives significant reduction in temperature_x000D_ SoC deviations compared to uniform use of all the cells even_x000D_ under unidirectional coolant flow. Thus reciprocating coolant flow_x000D_ is a redundant function for MLC based cell balancer. A specific_x000D_ contribution of the paper is the derivation of a state-space electrothermal_x000D_ model of a battery submodule €”for both unidirectional_x000D_ as well as reciprocating coolant flow€” under the switching action_x000D_ of an MLC, formulated in such a way that the OP is given by_x000D_ the solution of a convex optimization problem._x000D_
In this study, the simultaneous use of a multi-level converter (MLC) as a DC-motor drive and as an active battery cell balancer is investigated. MLCs allow each battery cell in a battery pack to be independently switched on and off, thereby enabling the potential non-uniform use of battery cells. By exploiting this property and the brake regeneration phases in the drive cycle, MLCs can balance both the state of charge (SoC) and temperature differences between cells, which are two known causes of battery wear, even without reciprocating the coolant flow inside the pack. The optimal control policy (OP) that considers both battery pack temperature and SoC dynamics is studied in detail based on the assumption that information on the state of each cell, the schedule of reciprocating air flow and the future driving profile are perfectly known. Results show that OP provides significant reductions in temperature and in SoC deviations compared with the uniform use of all cells even with uni-directional coolant flow. Thus, reciprocating coolant flow is a redundant function for a MLC-based cell balancer. A specific contribution of this paper is the derivation of a state-space electro-thermal model of a battery submodule for both uni-directional and reciprocating coolant flows under the switching action of MLC, resulting in OP being derived by the solution of a convex optimization problem.
The use of a three-phase multilevel converter (MLC) as an integrated cell balancer and motor driver is investigated for three-phase AC applications in EVs/HEVs/PHEVs. The paper analyzed an issue of additional battery losses caused by the flow of reactive and/or harmonic power from each power cell of the three-phase MLC battery system. The paper also investigates the size of shunt capacitor required for compensation of the losses to acceptable level. This study concludes that the size of the required capacitor is too big for the vehicle application unless some other active compensation is used as well. Another practical way to employ the MLC as a cell balancer is to use it in a cascaded connection with the conventional three-phase two-level voltage source inverter however it may not be a cost-effective solution either due to high component count.
A technology platform based on electrochemical transistors and electrochromic displays printed from organic materials on flexible substrates is presented. The devices are manufactured by using standard printing tools and operated below 3 V, and the device manufacturing is further simplified by that only a small set of materials is employed. Examples of printed electronic systems will be presented, such as active and passive matrix addressed displays, touchless sensor interfaces, secure user authentication applications and a novel approach to obtain reconfigurable systems utilizing self-adhesive active materials.
This paper examines the front-end process of inter-organizational IT innovation. In particular, it focuses on the nature and role of architectural knowledge. Such knowledge is important for development of architectures capable of serving the goals of heterogeneous actors and technologies. Yet, surprisingly little research has been done on how architectural knowledge may be developed through collective achievements. This paper presents a theoretical model of architectural knowledge development in inter-organizational IT innovation. Applying this model throughout an action research project within the Swedish transport industry, the paper identifies four dimensions of architectural knowledge that proved important for facilitating an industry-wide ubiquitous computing environment. The four dimensions are technology capability awareness, use context sensitivity, business model understanding, and boundary-spanning competence. We conclude the paper by outlining the theoretical and strategy implications of the model and the four dimensions of architectural knowledge. © 2008 Elsevier B.V. All rights reserved.
The sharing economy has been growing continuously in the last decade thanks to the proliferation of internet-based platforms that allow people to disintermediate the traditional commercial channels and to share excess resources and trade with one another effectively at a reasonably low transaction cost. Whereas early peer-to-peer platforms were designed to enable file sharing and goods trading, we recently witness the emergence of a new breed of peer-to-peer platforms that are designed for ordinary service sharing. Ordinary services entail intangible provisions and are defined as an economic activity that generates immaterial benefits and does not result in ownership of material goods. Based on a structured analysis of 41 internet-based rideshare platforms, we explore and layout the unique characteristics of peer-to-peer service sharing platforms based on three distinct temporal patterns that entail specific consequences for platform use as well as provide insights about their overall design imperative.
This paper examines the adoption of software product line engineering to implement digital differentiation of physical products. The introduction of such software-based variety can typically be challenging for firms innovating within the realm of a manufacturing paradigm. In particular, the mutual dependency between the organization design and product design of new product developing firms may counteract attempts to induce change through software product line engineering. On the basis of innovation theory and the notion of isomorphism, the paper presents a case study of digital differentiation at one of the world’s largest automakers, GlobalCarCorp. Relating to the literatures of software product lines and product families, the contribution of the paper is a lens through which to understand the role of isomorphism in implementing digital differentiation in new product development. In addition, practical implications are derived from this in-depth study.
An economy based on the exchange of capital, assets and services between individuals has grown significantly, spurred by proliferation of internet-based platforms that allow people to share underutilized resources and trade with reasonably low transaction costs. The movement toward this economy of "sharing" translates into market efficiencies that bear new products, reframe established services, have positive environmental effects, and may generate overall economic growth. This emerging paradigm, entitled the collaborative economy, is disruptive to the conventional company-driven economic paradigm as evidenced by the large number of peer-to-peer based services that have captured impressive market shares sectors ranging from transportation and hospitality to banking and risk capital. The panel explores economic, social, and technological implications of the collaborative economy, how digital technologies enable it, and how the massive sociotechnical systems embodied in these new peer platforms may evolve in response to the market and social forces that drive this emerging ecosystem.
An interaction protocol for cooperative platoon merge on highways is proposed. The interaction protocol facilitates a challenge scenario for the Grand Cooperative Driving Challenge (GCDC) 2016, where two platoons running on separate lanes merge into one platoon due to a roadwork in one of the lanes. Detailed interaction procedures, described with state machines of each vehicle are presented. A communication message set is designed to support platoon controllers to perform safe and efficient manoeuvres.
This paper presents an overview of current projects that deal with vehicle platooning. The platooning concept can be defined as a collection of vehicles that travel together, actively coordinated in formation. Some expected advantages of platooning include increased fuel and traffic efficiency, safety and driver comfort. There are many variations of the details of the concept such as: the goals of platooning, how it is implemented, mix of vehicles, the requirements on infrastructure, what is automated (longitudinal and lateral control) and to what level. The following projects are presented: SARTRE â a European platooning project; PATH â a California traffic automation program that includes platooning; GCDC â a cooperative driving initiative, SCANIA platooning and; Energy ITS â a Japanese truck platooning project.
In writings on the open source software development model, it is often argued that it is successful as a result of the gift economy that embraces activities in online communities. However, the theoretical foundations for this argument are seldom discussed and empirically tested. Starting with the 'classic' theories of gift giving, we discuss how they need to be developed in order to explain giftgiving practices in digital domains. In this paper, we argue that the gift economy is important, not only because it creates openness, but also because it organizes relationships between people in a certain way. Open source software development relies on gift giving as a way of getting new ideas and prototypes out into circulation. This also implies that the giver gets power from giving away. This power is used as a way of guaranteeing the quality of the code. We relate this practice to how gifts, in the form of new scientific knowledge, are given to the research community, and how this is done through peer review processes.
A key issue in many organizations is how to disseminate information in an effective way and, more importantly, how to make use of this information in order to create new knowledge. One way of addressing this problem is to focus on how information is socially transformed into knowledge. This includes how knowledge is handled in practice and how the knowledge produced is qualified as being something worth knowing and acting upon. Two well-established practices for doing this are the refereeing system and the peer review process. These are used in scientific communities as a means of validating and legitimating knowledge, for example by reviewing journal papers before publishing or project proposals before granting funds, etc. This paper argues that peer review is a useful concept when looking at knowledge creation and legitimization in organizations. The social meaning of peer review is to legitimize new knowledge by organizationally sanctioning it and thereby creating a platform for collective sense making. This paper uses an example from a field study in a pharmaceutical company in order to illustrate this argument. The study took place in a quality support department where the quality of health care products and processes was assessed. The organization had a need for fast and reliable updating of information that could influence how the production process of pharmaceuticals should be carried out. In order to cope with these problems the department established an ‘evaluation loop’, which shared several characteristics with the peer review process.
In this paper some aspects of the stereotyping of China and Japan are explored by using a sample of articles from a Swedish business magazine. The main objective is to show how stereotypes are adapted to capture new developments in economy and technology. During the years of high hopes for the largest Asian economies, stereotypes proved to be far from timeless and unchanging. Also a large number of metaphors were used to express perceived similarities between East and West, further undermining tradi-tional Western understanding of Asia as inert and eternally different. The recent decline of Japan put an end to this, creating a return to a vocabulary of cultural characterisations and explanations.
This paper presents findings from a design-oriented study focusing on emergency response work. Traditionally, Information Technology (IT) for emergency response work has included en route navigation advice, resource management, hazard material databases, property information repositories and situation reporting using sketching functionality. Now, a new class of IT has become available, namely mobile live video capabilities. This paper presents initial findings from a study on how mobile live video capabilities can improve information sharing and situation awareness in emergency response work.
Prior research on environmental innovation has highlighted the importance for the firm of a shared environmental vision but has not empirically explored why or what are its effects. The purpose of this paper is to analyze the effect of an environmental sustainability vision for the development and commercialization of environmental innovations. We conduct an in-depth, multilevel investigation of the development of green product lines in a multinational manufacturing firm, based primarily on interview data collected over five years. By analyzing the interaction between environmental vision and the product development process as an interaction between problem formulation and the search for problem solutions, we explain how and why a shared environmental vision can accelerate environmental innovation. Specifically, we show that a shared environmental vision can lead to an increase in the number of application areas, and increased sales of previously customized solutions but that the efficacy of the shared vision is dependent on a good match between the environmental problems being focused on, and the core competencies of the firm.
While ethnography is an established part of CSCW research, teaching and learning ethnography presents unique and distinct challenges. This paper discusses a study of fieldwork and analysis amongst a group of students learning ethnography as part of a CSCW & design course. Studying the students’ practices we explore fieldwork as a learning experience, both learning about fieldsites as well as learning the practices of ethnography. During their fieldwork and analysis the students used a wiki to collaborate, sharing their field and analytic notes. From this we draw lessons for how ethnography can be taught as a collaborative analytic process and discuss extensions to the wiki to better support its use for collaborating around fieldnotes. In closing we reflect upon the role of learning ethnography as a practical hands on – rather than theoretical – pursuit.
Ambitions about deep interdisciplinary education may face barriers. However, interaction between student groups does not have to be difficult. We report on a collaboration including more than 200 students from different subject areas, at different curricular stages in a multidisciplinary concept workshop. By engaging with an external event we avoided some of the challenges involved in aligning agendas, while remaining true to the ambitions of giving students Concrete Experience and opportunity to Reflect in and on actions, balancing the ambitions of raising awareness of the relation between subjects and engaging students in collaborating in problem solving based on skills and knowledge from their respective discipline. Our results show how collaborating with industry can help bridge some of the challenges with internal collaboration between students from different disciplines.
Intersection management is one of the most challenging problems within the transport system. Traffic light-based methods have been efficient but are not able to deal with the growing mobility and social challenges. On the other hand, the advancements of automation and communications have enabled cooperative intersection management, where road users, infrastructure, and traffic control centers are able to communicate and coordinate the traffic safely and efficiently. Major techniques and solutions for cooperative intersections are surveyed in this paper for both signalized and nonsignalized intersections, whereas focuses are put on the latter. Cooperative methods, including time slots and space reservation, trajectory planning, and virtual traffic lights, are discussed in detail. Vehicle collision warning and avoidance methods are discussed to deal with uncertainties. Concerning vulnerable road users, pedestrian collision avoidance methods are discussed. In addition, an introduction to major projects related to cooperative intersection management is presented. A further discussion of the presented works is given with highlights of future research topics. This paper serves as a comprehensive survey of the field, aiming at stimulating new methods and accelerating the advancement of automated and cooperative intersections.
With intensive research and field operational tests over the intelligent transportation area and the advancements of information and communication technologies, intelligent transportation systems reach the stage of deployment. EU focuses on cooperative intelligent transportation systems and confirms the finalization of the first release of the standards, paving the way for deployment in the coming years. This paper presents the concept of EU's cooperative intelligent transportation systems and describes in detail the functional architecture, together with highlights of related standardsthat have been finalized in Release 1. Latest updates of the cooperative intelligent transportation systems are provided for both industry and academia, aiming at helping to accelerate cooperative mobility.
Despite the existing regulation efforts and measures, vehicles with dangerous goods still pose significant risks on public safety, especially in road tunnels. Solutions based on cooperative intelligent transportation system (C-ITS) are promising measures, however, they have received limited attention. We propose C-ITS applications that coordinate dangerous goods vehicles to minimize the risk by maintaining safe distances between them in road tunnels. Different mechanisms, including global centralized coordination, global distributed coordination, and local coordination, are proposed and investigated. A preliminary simulation is performed and demonstrates their effectiveness.
Conventional bike-sharing schemes have been introduced in cities as an urban mobility option, reducing car usage and alleviating public transport; however, cycling shares in Göteborg is one of the lowest in Europe. Göteborg has been dedicated to increase the share of sustainable transport in the city. The Electric bicycle (E-bike), which offers a greater form of service than the conventional bicycle, then appears to be rather interesting to policy makers. This study is carried out with the goal to open the door for E-bikes in Göteborg by identifying potential for change from car users to E-bike users. First, the current situation of Swedish perception on cycling and policy were analysed with a literature review. Second, we explore whether E-bikes can remove barriers or provide the same benefit of the alternative modes for people in Göteborg. At the third phase, the geographical potential of E-bikes in Göteborg was identified on three bases: the ratio of cyclist using cars for commuting purposes, travel distance, and the barriers removed. The result suggested that E-bikes theoretically remove the barriers expressed by 53% of people in Göteborg when comparing to regular bicycles. A public E-bike pool is a good solution for overcoming the first two phases of behavioural change, by demonstrating the technology and creating a public supply of E-bikes. Hisingen is the area with the greatest potential to adopt E-biking habits, setting up an E-bike pool in Hisingen can hypothetically substitute around 5% of commuting trips done by the car users who have the capacity to cycle. For the entire Göteborg area, up to 4% of the trips less than 10 km could be replaced by E-bikes. Together with the proper policy strategy, a change towards sustainable transport mode could be realized supported by wide acceptance among the general public.
Information systems as an artefact-oriented discipline require a strong interaction between researchers, developers and users regarding design of, development of, and the study of the use of digital artefacts in social settings. During recent years, performing research in a design science research spirit has gained increasing interest. In larger scale design research endeavours, access to systems development capabilities becomes necessary. Such a unit, InnovationLab, was established in 2006 in a university setting in Sweden. In this paper we are investigating the 5 years' experience of running this InnovationLab. Our findings point to an innovation lab being valuable for research in general and especially for design science research. However, in order to balance the business of an innovation lab, it will be necessary to provide services for other stakeholders (such as administrative units, teachers, and students) as a means for developing systems development capability aimed at supporting researchers.
The electrification of road transport is accelerating globally, propelled by a mix of environmental concerns, legislative mandates, business opportunities. Relying to a larger extent on electricity in the transportation sector provides new opportunities to reduce carbon dioxide (CO2) emissions, fossil fuel consumption, local air pollution by improving energy efficiency employing renewable energy. As part of this development, leading vehicle manufacturers are currently making a substantial effort to provide hybrid electric vehicles (HEVs), plug-in hybrid EVs (PHEVs), pure EVs to the market._x000D_
The Grand Cooperative Driving Challenge (GCDC), with the aim to boost the introduction of cooperative automated vehicles by means of wireless communication, is presented. Experiences from the previous edition of GCDC, which was held in Helmond in the Netherlands in 2011, are summarized, and an overview and expectations of the challenges in the 2016 edition are discussed. Two challenge scenarios, cooperative platoon merge and cooperative intersection passing, are specified and presented. One demonstration scenario for emergency vehicles is designed to showcase the benefits of cooperative driving. Communications closely follow the newly published cooperative intelligent transport system standards, while interaction protocols are designed for each of the scenarios. For the purpose of interoperability testing, an interactive testing tool is designed and presented. A general summary of the requirements on teams for participating in the challenge is also presented.
Current transportation systems face great challenges due to the increasing mobility. Traffic accidents, congestion, air pollution, etc., are all calling for new methods to improve the transportation system. With the US legislation in progress over vehicle communications and EU’s finalization of the basic set of standards over cooperative intelligent transportation systems (C-ITS), vehicular ad hoc network (VANET) based applications are expected to address those challenges and provide solutions for a safer, more efficient and sustainable future intelligent transportation systems (ITS). In this chapter, transportation challenges are firstly summarized in respect of safety, efficiency, environmental threat, etc. A brief introduction of the VANET is discussed along with state of the art of VANET-based applications. Based on the current progress and the development trend of VANET, a number of new features of future VANET are identified, together with a set of potential future ITS applications. The on-going research and field operational test projects, which are the major enabling efforts for the future VANET-based C-ITS, are presented. The chapter is of great interest to readers working within ITS for current development status and future trend within the C-ITS area. It is also of interest to general public for an overview of the VANET enabled future transportation system.
Cooperative speed harmonization based on floating car data aiming at improving manoeuvrability in a highly utilized intersection is presented. Cooperative Intelligent Transportation Systems (C-ITS) aims at gather information about the current traffic situation based on wireless communication and provide aggregated information back to the road users in order to improve e.g. efficiency, safety and/or comfort. Simulations show that the proposed speed harmonization application is capable of lowering the CO2 emissions with up to 11%, increasing the average speed with up to 14% and reducing the travel time with up to 16% for all vehicles in the simulation. It is also found that not only the cooperative vehicles benefit from the application but also the non-equipped vehicles. Furthermore, the cooperative traffic simulator has been shown to be a valuable tool for investigating how C-ITS applications may be utilized to develop future traffic system.
Data mining techniques based on Random forests are explored to gain knowledge about data in a Field Operational Test (FOT) database. We compare the performance of a Random forest, a Support Vector Machine and a Neural network used to separate drowsy from alert drivers. 25 variables from the FOT data was utilized to train the models. It is experimentally shown that the Random forest outperforms the other methods while separating drowsy from alert drivers. It is also shown how the Random forest can be used for variable selection to find a subset of the variables that improves the classification accuracy. Furthermore it is shown that the data proximity matrix estimated from the Random forest trained using these variables can be used to improve both classification accuracy, outlier detection and data visualization.
This paper presents a novel approach to modelling visual distraction of bicyclists. A unique bicycle simulator equipped with sensors capable of capturing the behaviour of the bicyclist is presented. While cycling two similar scenario routes, once while simultaneously interacting with an electronic device and once without any electronic device, statistics of the measured speed, head movements, steering angle and bicycle road position along with questionnaire data are captured. These variables are used to model the self-assessed distraction level of the bicyclist. Data mining techniques based on random forests, support vector machines and neural networks are evaluated for the modelling task. Out of the total 71 measured variables a variable selection procedure based on random forests is able to select a fraction of those and consequently improving the modelling performance. By combining the random forest-based variable selection and support vector machine-based modelling technique the best overall performance is achieved. The method shows that with a few observable variables it is possible to use machine learning to model, and thus predict, the distraction level of a bicyclist.
A data proximity matrix is an important information source in random forests (RF) based data mining, including data clustering, visualization, outlier detection, substitution of missing values, and finding mislabeled data samples. A novel approach to estimate proximity is proposed in this work. The approach is based on measuring distance between two terminal nodes in a decision tree. To assess the consistency (quality) of data proximity estimate, we suggest using the proximity matrix as a kernel matrix in a support vector machine (SVM), under the assumption that a matrix of higher quality leads to higher classification accuracy. It is experimentally shown that the proposed approach improves the proximity estimate, especially when RF is made of a small number of trees. It is also demonstrated that, for some tasks, an SVM exploiting the suggested proximity matrix based kernel, outperforms an SVM based on a standard radial basis function kernel and the standard proximity matrix based kernel.
Allt fler offentliga myndigheter står inför eller har delvis genomfört tillängliggörande av interna data till allmänheten - s.k. öppna data. Detta förväntas leda till nya innovativa tjänster utvecklade av intermediärer - tredjepartsutvecklare. För att stimulera sådana utvecklingsaktiviteter behöver de öppna datakällorna skapa värde för tredjepartsutvecklare. Det projekt, i vilken denna rapport är en slutredovisning, har tagit fram verktyg för att mäta tredjepartsutvecklares upplevda värde av Trafikverkets öppna data.
Arbetet med att identifiera hur en organisation kan skapa värde med öppna datatjänster vägledde projektet till att undersöka existerande forskning och erfarenhet om hur värde skapas inom tjänstesektorn. Rapporten presenterar sex områden vilka skapar värde för tredjepartsutvecklare av Trafikverkets öppna datatjänster.
Projektet genomförde djupintervjuer med tredjepartsutvecklare som visar på behov och synpunkter på hur Trafikverket kan skapa ett ökat värde med öppna datatjänster.
Due to the complexity of today's embedded systems and time-to-market competition between companies developing embedded systems, system architects have to perform a complex task. To design a system which meets all its quality requirements becomes increasingly difficult because of customer demand for new innovative user functions. Methods and tools are needed to assist the architect during system design. The goal of this paper is to show how metaheuristic optimization approaches can improve the process of designing efficient architectures for a set of given quality attributes. A case study is conducted in which an architecture optimization framework is applied to an existing sub-system in the automotive industry. The case study shows that metaheuristic optimization approaches can find efficient solutions for all quality attributes while fulfilling given constraints. By optimizing multiple quality attributes the framework proposes revolutionary architecture solutions in contrast to human architects, who tend to propose solutions based on previous architectures. Although the case study shows savings in manual effort, it also shows that the proposed architecture solutions should be assessed by the human architect. So, the paper demonstrates how an architecture optimization framework complements the domain knowledge and experience of the architect.
This article presents a platform for flexible hardware- and model-in-the-loop integration of driver assistance systems in a driving simulator environment. The new platform combines the capabilities of a full-scale vehicle electrical systems test environment with the driver interaction evaluation capabilities of an advanced driving simulator. This enables faster development cycles for driver assistance systems by allowing easy transition between simulation configurations used in the development process (e.g. Software-in-the-Loop and Hardware-in-the-Loop) and, crucially, includes the driving simulator as a key part in all stages of the process. The presented integrated test environment enables easy and fast adaptation to include different driver assistance systems of varying degrees of development maturity and functional integration in an advanced driving simulator. Generic interfaces guarantee flexibility and the architecture enables scalability of the development environment for new functions, ranging from desktop simulation to advanced driving simulators. In this integrated test facility even complex interactive full system tests of potential dangerous scenarios can be easily repeated. As an example a test scenario for a system with autonomous steer intervention will be presented and discussed.
The next generation of intranets should facilitate the structuring of information as well as the organizing of communication in networking organizations. For many organizations, one step in that direction is to structure information by adding metadata. We have encountered problems when applying Dublin Core, a metadata element set developed for discovery of existing information resources on the public Internet, on an extensive intranet. Our conclusion, argued in this paper, is that these problems are a consequence of trying to describe information resources without taking into account the context in which end users create and consume information. The next generation of intranets calls for a more contextual approach. The contribution of this paper is such an approach. We propose a framework including: (1) A model for describing three different areas of resources: business, information and communication, and integrating the resources description areas by means of generic classes, constrains and relations. (2) An extension to the model describing and integrating nodes and relations in networking organizations. (3) An extension to the model describing and organizing the communication of information in the business. The framework suggests an extensible use of RDF (Resource Description Framework) in a business context.
This paper compares the robustness of three different battery State of Charge (SoC) estimation algorithms: the Extended Kalman Filter (EKF), the Unscented Kalman Filter (UKF) and the H∞ filter. Their performance when subject to disturbances such as parameter uncertainties, different sensor noise characteristics and sensitivity to tuning of the filter are examined. Simulations show that the appropriate choice of observer algorithm will depend on battery chemistry as well as on the intended application. For batteries with a strong correlation between SoC and OCV, the UKF is robust to disturbances such as sensor bias. The H∞ observer shows performance on par with the UKF but the variability of the estimation errors are larger. The EKF is a good all-round choice.
In online automotive applications, look-up tables are often used to model nonlinearities in component models that are to be valid over large operating ranges. If the component characteristics change with ageing or wear, these look-up tables must be updated online. Here, a method is presented where a Kalman filter is used to update the entire look-up table based on local estimation at the current operating conditions. The method is based on the idea that the parameter changes observed as a component ages are caused by physical phenomena having effect over a larger part of the operating range that may have been excited. This means that ageing patterns at different operating points are correlated, and these correlations are used to drive a random walk process that models the parameter changes. To demonstrate properties of the method, it is applied to estimate the ohmic resistance of a lithium-ion battery. In simulations the complete look-up table is successfully updated without problems of drift, even in parts of the operating range that are almost never excited. The method is also robust to uncertainties, both in the ageing model and in initial parameter estimates.
Recursive algorithms, such as recursive least squares (RLS) or Kalman filters, are commonly used in battery management systems to estimate the electrical impedance of the battery cell. However, these algorithms can in some cases run into problems with bias and even divergence of the estimates. This article illuminates problems that can arise in the online estimation using recursive methods, and lists modifications to handle these issues. An algorithm is also proposed that estimates the impedance by separating the problem in two parts; one estimating the ohmic resistance with an RLS approach, and another one where the dynamic effects are estimated using an adaptive Kalman filter (AKF) that is novel in the battery field. The algorithm produces robust estimates of ohmic resistance and time constant of the battery cell in closed loop with SoC estimation, as demonstrated by both in simulations and with experimental data from a lithium-ion battery cell.
InSb-based quantum dots grown by metal-organic vapor-phase epitaxy (MOVPE) on InAs substrates are studied for use as the active material in interband photon detectors. Long-wavelength infrared (LWIR) photoluminescence is demonstrated with peak emission at 8.5 μm and photoresponse, interpreted to originate from type-II interband transitions in a p-i-n photodiode, was measured up to 6 μm, both at 80 K. The possibilities and benefits of operation in the LWIR range (8-12 μm) are discussed and the results suggest that InSb-based quantum dot structures can be suitable candidates for photon detection in the LWIR regime.