RISE Research Institutes of Sweden
Recent publications
A quantitative understanding of dynamic lane‐changing interaction patterns is indispensable for improving the decision‐making of autonomous vehicles (AVs), especially in mixed traffic with human‐driven vehicles. This paper develops a novel framework combining the hidden Markov model (HMM) and graph structure to identify the difference in dynamic interaction patterns between mandatory lane changes (MLC) and discretionary lane changes (DLC). An HMM is developed to separate the interaction patterns considering heterogeneity in lane‐changing processes and reveal the temporal properties of these patterns. Conditional mutual information is used to quantify the interaction intensity, and the graph structure is used to characterize the relationship between vehicles. Finally, a case study is conducted to demonstrate the practical value of the proposed framework and validate its effectiveness in predicting lane‐changing trajectories. Based on the lane‐changing events extracted from a real‐world trajectory dataset, the proposed analytical framework is applied to model MLC and DLC under congested traffic with levels of service E and F. The results show that there could be multiple heterogeneous dynamic interaction patterns in a lane‐changing process. A comparison of MLC and DLC demonstrates that MLC involves more intense interactions and more frequent transitions of the interaction network structure, while the evolution rules of interaction patterns in DLC do not exhibit a clear trend. The findings in this study are useful for understanding the connectivity structure between vehicles in lane‐changing interactions and for designing safe and smooth driving decision‐making models for AVs and advanced driver‐assistance systems.
Background Stress reflects physical and psychological reactions to imposing demands and is often measured using self-reports. A widely-used instrument is the Perceived Stress Scale (PSS), intended to capture more general aspects of stress. A Swedish translation of the PSS is available but has not previously been examined using modern test theory approaches. The aim of the current study is to apply Rasch analysis to further the understanding of the PSS’ measurement properties, and, in turn, improve its utility in different settings. Methods Data from 793 university students was used to investigate the dimensionality of different version of the PSS (14, 10, and 4 items) as well as potential response patterns among the participants. Results The current study demonstrates that the PSS-14 has two separate factors, divided between negatively worded items (perceived stress) and positively worded items (perceived [lack of] control), although with only the negative subscale exhibiting good reliability. Response patterns were analyzed using Differential Item Functioning, which did not find an influence of gender on any of the items, but for age regarding the positive subscale (items 6 and 9). The PSS-10 also demonstrated adequate reliability for the negative subscale, but the PSS-4 was not deemed suitable as a unidimensional scale. Conclusions Based on the results, none of the versions of the PSS should be used by sum-scoring all of the items. Only the negative items from the PSS-14 or PSS-10 can be used as unidimensional scales to measure general aspects of stress. As for different response patterns, gender may nevertheless be important to consider, as prior research has found differences on several items. Meanwhile, content validity is discussed, questioning the relevance of anger and being upset when measuring more general aspects of stress. Finally, a table to convert the PSS-7 (i.e., negative items) ordinal sum scores to interval level scores is provided.
For telemedicine, Wireless Body Area Network (WBAN) offers enormous benefits where a patient can be remotely monitored without compromising the mobility of remote treatments. With the advent of high capacity and reliable wireless networks, WBANs are used in several remote monitoring systems, limiting the COVID-19 spread. The sensitivity of telemedicine applications mandates confidentiality and privacy requirements. In this paper, we propose a secure WBAN-19 telemedicine system to overcome the pervasiveness of contagious deceases utilizing a novel aggregate identity-based signcryption scheme with an equality test feature. We demonstrate a security analysis regarding indistinguishable adaptive chosen-ciphertext attack (IND-CCA2), one-way security against adaptive chosen-ciphertext attack (OW-CCA2), and unforgeability against adaptive chosen-message attack (EUF-CMA) under the random oracle model. The security analysis of the scheme is followed by complexity evaluations where the computation cost and communication overhead are measured. The evaluation demonstrates that the proposed model is efficient and applicable in telemedicine systems with high-performance capacities.
This paper explores the concept of green design in the context of production, focusing on investment projects for production equipment design and acquisition by a manufacturing firm. Research towards making manufacturing and production related activities more sustainable is increasing. In the manufacturing sector, environmental sustainability tends to be more commonly approached from the operations perspective. However, the decisions taken in the design phase of the production equipment significantly impact the operations phase. Therefore, proactive design approaches for sustainability applied in product design settings could be transferred to the design of the production equipment to build in green aspects from the outset. This study explores the research questions of what green production equipment design entails and how the concept of green design has evolved in the context of production. Overall, this conceptual paper highlights the importance of incorporating green design principles from the outset of the production design. Transferable methodological issues are also explored for further detailed investigation in the production equipment design context. Strong collaboration between equipment suppliers and the buying manufacturer that aims to integrate sustainability as part of requirements is proposed as an enabler for the way forward. The paper also provides insights into the evolution of the concept in this context for possible future research.
The research in this paper focused on (i) to increase the knowledge about the strategic role of automation technology and (ii) how automation technology investment decisions can be aligned with the strategy in manufacturing SMEs. This paper describes the design, application, and evaluation of the Strategic Development Map (SDM) in three settings, whereof two manufacturing SMEs. The SDM was also applied in more than 500 SMEs in a Swedish initiative called the Robot Lift. The SDM was derived from existing literature about Toyota management principles and thereafter adapted to the topic. The process of designing, testing, and evaluating the tool was inspired by design science research. It also contains explanations of the outcomes and mechanisms that lead to the successful adaptation and use of the SDM. The SDM provides a structured guidance process to understand the strategic role of automation technology investments in SMEs. This process can support companies towards a deeper understanding of the current state, target state and obstacles and challenges to reach the target with a focus on automation technology investments. The SDM was emphasized by companies and external coaches as very simple to understand and use. Using the SDM increased involvement and knowledge about strategic role of automation technology.
The effect on softwood fiber wall nanostructure of kraft cooking, oxygen delignification and refining was evaluated by X-ray scattering. A recently developed simulation method for modelling small angle X-ray scattering (SAXS) data was used to estimate the apparent average sizes of solids (AAPS) and interstitial spaces in the fiber wall (AACS). Fiber saturation point and wide angle X-ray scattering were also used to calculate the pore volume in the fiber wall and the crystallite size of the fibril, respectively. The experimental modelled SAXS data was able to give consistent values for each kraft-cooked and oxygen-delignified pulp. Kraft delignification seems to have the major influence on the fiber nanostructure modification, while oxygen delignification has little or no significant impact even for different kappa numbers. The particle sizes values were more stable than the cavities sizes and no significant differences were seen between different delignification processes, refining or delignification degree. Pulps evaluated after PFI-refining, showed an increase in the fiber wall porosity evaluated by FSP and an increase in the interstitial spaces in the fiber wall, while the crystallite size and the particle sizes were very little or not affected at all.
Assembly is crucial in the automotive industry, and regulations aimed to increase circularity impact the production systems. From this perspective different strategies are emerging related to sustainability and to the End-of-life Vehicles directive, perspectives often captured by “R-words” like Reuse, Recycle, Rethink etc. This paper is based on a literature search inspired by different R-words related to circularity and assembly in the automotive industry in combination with industrial workshops on the same theme. The results explore what challenges to manage during the ongoing green transition in the context of assembly in automotive. Recover, Repair, Reuse and Recycle are the most common terms found in the literature. Furthermore, Remanufacturing stands out as of particular interest to the automotive industry. However, based on the industrial workshops, Rethink as a collective word is an important perspective as well. The conclusions indicate that digitalization can be an enabler but also that there is a need for developing a common understanding about definitions and utilization of engineering tools supporting circularity.
Serverless applications spanning the cloud and edge require flexible programming frameworks for expressing compositions across the different levels of deployment. Another critical aspect for applications with state is failure resilience beyond the scope of a single dataflow graph that is the current standard in data streaming systems. This paper presents Portals, an interactive, stateful dataflow composition framework with strong end-to-end guarantees. Portals enables event-driven, resilient applications that span across dataflow graphs and serverless deployments. The demonstration exhibits three scenarios in our multi-dataflow streaming-based system: dynamically composing a stateful serverless application; an interactive cloud and edge serverless application; and a Portals browser playground.
Model‐based test design is increasingly being applied in practice and studied in research. Model‐based testing (MBT) exploits abstract models of the software behaviour to generate abstract tests, which are then transformed into concrete tests ready to run on the code. Given that abstract tests are designed to cover models but are run on code (after transformation), the effectiveness of MBT is dependent on whether model coverage also ensures coverage of key functional code. In this article, we investigate how MBT approaches generate tests from model specifications and how the coverage of tests designed strictly based on the model translates to code coverage. We used snowballing to conduct a systematic literature review. We started with three primary studies, which we refer to as the initial seeds. At the end of our search iterations, we analysed 30 studies that helped answer our research questions. More specifically, this article characterizes how test sets generated at the model level are mapped and applied to the source code level, discusses how tests are generated from the model specifications, analyses how the test coverage of models relates to the test coverage of the code when the same test set is executed and identifies the technologies and software development tasks that are on focus in the selected studies. Finally, we identify common characteristics and limitations that impact the research and practice of MBT: (i) some studies did not fully describe how tools transform abstract tests into concrete tests, (ii) some studies overlooked the computational cost of model‐based approaches and (iii) some studies found evidence that bears out a robust correlation between decision coverage at the model level and branch coverage at the code level. We also noted that most primary studies omitted essential details about the experiments.
Organic semiconductors are a family of pi-conjugated compounds used in many applications, such as displays, bioelectronics, and thermoelectrics. However, their susceptibility to processing-induced contamination is not well understood. Here, it is shown that many organic electronic devices reported so far may have been unintentionally contaminated, thus affecting their performance, water uptake, and thin film properties. Nuclear magnetic resonance spectroscopy is used to detect and quantify contaminants originating from the glovebox atmosphere and common laboratory consumables used during device fabrication. Importantly, this in-depth understanding of the sources of contamination allows the establishment of clean fabrication protocols, and the fabrication of organic field effect transistors (OFETs) with improved performance and stability. This study highlights the role of unintentional contaminants in organic electronic devices, and demonstrates that certain stringent processing conditions need to be met to avoid scientific misinterpretation, ensure device reproducibility, and facilitate performance stability. The experimental procedures and conditions used herein are typical of those used by many groups in the field of solution-processed organic semiconductors. Therefore, the insights gained into the effects of contamination are likely to be broadly applicable to studies, not just of OFETs, but also of other devices based on these materials.
As indicated by the Japanese government's 2050 Carbon Neutral Declaration, efforts to achieve a decarbonized society are becoming an increasingly important issue. Using forest resources is one of the effective means to realize a sustainable carbon-neutral society. As a method for producing pulp from lignocellulose materials of plants such as wood, digestion using alkali or sulfite is generally used. After the lignin component is mainly decomposed by this cooking treatment, the lignin is removed by filtration and washing to produce pulp. Although natural resources such as timber are recyclable, excessive deforestation is regulated from the point of view of environment and ecosystem preservation, and the price of timber is increasing. Therefore, in the production of pulp, for example, it is becoming important to increase the amount of pulp produced per unit of raw wood and to produce high-quality pulp products. As a method to solve these problems, there is a method of using cooking aids(accelerators)for the purpose of increasing the efficiency of cooking and improving the yield of pulp per unit of raw wood. Furthermore, in recent years, there has been a demand for safer digestion accelerators. This time, we explored various compounds, repeated laboratory evaluations, and developed a new digestion accelerator. However, in order to grasp the cooking capacity more accurately, we thought that an evaluation that reproduced the industrial process was necessary. Under these circumstances, we contacted the RISE Research Institutes of Sweden AB.(RISE)and conducted an evaluation of a new digestion accelerator. As a result, it was observed that the pulp yield tended to improve compared to the case where the was not used. Evaluation is ongoing. At the same time, we visited RISE in June 2022, witnessed the laboratory evaluation, and observed the equipment and methods, etc., and found that the RISE cooking evaluation method was more reasonable. In this presentation, we will explain the theoretical concept of the digestion accelerator developed by our company, and the method and results of the digestion test conducted at RISE.
Additive manufacturing (AM) allows for optimized part design, reducing weight compared to conventional manufacturing. However, the microstructure, surface state, distribution, and size of internal defects (e.g., porosities) are very closely related to the AM fabrication process and post-treatment operations. All these parameters can have a strong impact on the corrosion and fatigue performance of the final component. Thus, the fatigue-corrosion behavior of the 3D-printed (L-PBF) AlSi10Mg aluminum alloy has been investigated. The influence of load sequence (sequential vs. combined) was explored using Wöhler diagrams. Surface roughness and defects in AM materials were examined, and surface treatment was applied to improve surface quality. The machined specimens showed the highest fatigue properties regardless of load sequence by improving both the roughness and removing the contour layer containing the highest density of defect. The impact of corrosion was more pronounced for as-printed specimens as slightly deeper pits were formed, which lowered the fatigue-corrosion life. As discussed, the corrosion, fatigue and fatigue-corrosion mechanisms were strongly related to the local microstructure and existing defects in the AM sample.
Although it is clear that i-frame approaches cannot stand alone, the impact of s-frame changes can plateau. Combinations of these approaches may best reflect what we know about behavior and how to support behavioral change. Interactions between i-frame and s-frame thinking are explored here using two examples: alcohol consumption and meat consumption.
A well‐known drawback with LCD‐displays in cold is a slow pixel response leading to poor picture quality. Low temperatures can constitute a hazard in viewing important displays in cars. Perceptual experiments with 20 test‐persons were conducted to find clear and acceptable ranges on screens simulating distortions in low temperatures. The results showed perception over clear and acceptable image quality was impaired beyond ‐20°C for the LCD‐screen in the experiments.
Driver behaviour monitoring is a broad area of research, with a variety of methods and approaches. Distraction from the use of electronic devices, such as smartphones for texting or talking on the phone, is one of the leading causes of vehicle accidents. With the increasing number of sensors available in vehicles, there is an abundance of data available to monitor driver behaviour, but it has only been available to vehicle manufacturers and, to a limited extent, through proprietary solutions. Recently, research and practice have shifted the paradigm to the use of smartphones for driver monitoring and have fuelled efforts to support driving safety. This systematic review paper extends a preliminary, previously carried out author-centric literature review on smartphone-based driver monitoring approaches using snowballing search methods to illustrate the opportunities in using smartphones for driver distraction detection. Specifically, the paper reviews smartphone-based approaches to distracted driving behaviour detection, the smartphone sensors and detection methods applied, and the results obtained.
The pseudocereal buckwheat is one of the ancient domesticated crops. The aim of the present review was to outline the potential of buckwheat as an agricultural crop and brings studies on buckwheat into a new larger perspective combining current knowledge in agricultural history and practice, nutritional and sensory properties, as well as possible benefits to human health. Historically, buckwheat was an appreciated crop because of its short growth period, moderate requirements for growth conditions, and high adaptability to adverse environments. Nowadays, interest in buckwheat-based food has increased because of its nutritional composition and many beneficial properties for human health. Buckwheat is a rich course of proteins, dietary fibers, vitamins, minerals, and bioactive compounds, including flavonoids. Moreover, it contains no gluten and can be used in the production of gluten-free foods for individuals diagnosed with celiac disease, non-celiac gluten sensitivity, or wheat protein allergies. Buckwheat is traditionally used in the production of various foods and can be successfully incorporated into various new food formulations with positive effects on their nutritional value and attractive sensory properties. Further research is needed to optimize buckwheat-based food development and understand the mechanism of the health effects of buckwheat consumption on human well-being.
The quest for eco‐friendly materials with anticipated positive impact for sustainability is crucial to achieve the UN sustainable development goals. Classical strategies of composite materials can be applied on novel nanomaterials and green materials. Besides the actual technology and applications also processing and manufacturing methods should be further advanced to make entire technology concepts sustainable. Here, they show an efficient way to combine two low‐cost materials, cellulose and zinc oxide (ZnO), to achieve novel functional and “green” materials via paper‐making processes. While cellulose is the most abundant and cost‐effective organic material extractable from nature. ZnO is cheap and known of its photocatalytic, antibacterial, and UV absorption properties. ZnO nanowires are grown directly onto cellulose fibers in water solutions and then dewatered in a process mimicking existing steps of large‐scale papermaking technology. The ZnO NW paper exhibits excellent photo‐conducting properties under simulated sunlight with good ON/OFF switching and long‐term stability (90 minutes). It also acts as an efficient photocatalyst for hydrogen peroxide (H 2 O 2 ) generation (5.7 × 10 ⁻⁹ m s ⁻¹ ) with an envision the possibility of using it in buildings to enable large surfaces to spontaneously produce H 2 O 2 at its outer surface. Such technology promise for fast degradation of microorganisms to suppress the spreading of diseases.
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974 members
Bo N. Schenkman
  • Digital Systems
Dhrubajyoti Bhattacharjya
  • SP Measurement Technology
Per Olof Hedekvist
  • SP Measurement Technology
Kenny Hey Tow
  • Fibre and Photonics
Göteborg, Sweden
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