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Lightcurves, Rotation Periods, and Colors for Vera C. Rubin Observatory’s First Asteroid Discoveries
No full textWe present lightcurves, rotation periods, and colors for the first asteroid discoveries made with the NSF-DOE Vera C. Rubin Observatory. These are the first science results derived from the 2103 asteroid discoveries released as part of the Rubin First Look (RFL) media event on 2025 June 23, in which the first LSST Camera commissioning images were released. The ∼340,000 observations in which the discoveries were made span nine nights between 2025 April 21 and May 5. With a limiting single-epoch 5σ depth of ∼23–25 mag and dense temporal sampling under an irregular, commissioning-driven cadence, the RFL observations provide an ideal test bed for determination of rotation periods, including sensitivity to rapid rotation. We model lightcurves and derive rotation periods and colors for the ∼2000 objects. We find 75 main-belt asteroids (MBAs) and one near-Earth object (NEO) with reliable rotation periods spanning 0.031–21.3 hr and a photometric precision in the range of 0.05–0.15 mag. We find 19 superfast rotators with periods shorter than the 2.2 hr spin barrier. Rubin-discovered MBA 2025 MN45 is the fastest-rotating d > 0.5 km known asteroid with a rotation period of 1.9 minutes; along with NEO 2025 MJ71 (1.9 minutes) and Rubin-discovered MBAs 2025 MK41 (3.8 minutes), 2025 MV71 (13 minutes), and 2025 MG56 (16 minutes), these five super- to ultrafast rotators join a couple of NEOs as the fastest-spinning subkilometer asteroids known. As this study demonstrates, even in early commissioning, Rubin is successfully probing a previously sparsely sampled region of the subkilometer size−spin rate regime for MBAs.Full text license: CC BY 4.0;For funding information, see: https://iopscience.iop.org/article/10.3847/2041-8213/ae2a30</p
Agentic TinyML for Intent-Aware Handover in 6G Wireless Networks
No full textAs sixth-generation (6G) wireless networks evolve into increasingly Artificial Intelligence (AI)-driven, user-centric ecosystems, traditional reactive handover mechanisms demonstrate limitations, especially in mobile edge computing and autonomous agent-based service scenarios. This manuscript introduces the Wireless AI Agent Network (WAAN), a cross-layer framework designed to enable intent-aware and proactive handovers in 6G networks. WAAN embeds lightweight Tiny Machine Learning (TinyML) agents as autonomous, negotiation-capable entities across heterogeneous edge nodes that contribute to intent propagation and network adaptation. To ensure continuity across mobility-induced disruptions, WAAN incorporates semi-stable Rendezvous Points (RPs) that serve as coordination anchors for context transfer and state preservation. The framework’s operational capabilities are demonstrated through a multimodal environmental control case study, highlighting its effectiveness in maintaining user experience under mobility. Finally, the article discusses key challenges and future opportunities associated with the deployment and evolution of WAAN.Funder: Research Council of Finland (369116); Business Finland through the Neural Pub/Sub Project (8754/31/2022); Digital Twinning of Personal Area Networks for Optimized Sensing and Communication Project (8782/31/2022);Full text license: CC BY</p
Klimatanpassad stadsutveckling i Norrbotten : En studie om hur blågröna strukturer kan implementeras för att stärka sociala värden i ett förändrat klimat.
No full textThis study examines how architectural solutions can contribute to climate adaptation in urban development in Norrbotten, with particular emphasis on human comfort in Luleå, Jokkmokk, and Kiruna. The conditions for spending time outdoors in subarctic cities vary substantially over the course of the year. Periods of both prolonged and limited daylight, as well as major variations in temperature and weather, are aspects that must be considered in the development of cities and the life between buildings. The focus of this study therefore concerns how climate adaptation measures can be integrated into urban development in order to create attractive and sustainable communities. The study is based on a literature review, with the aim of mapping existing material and recurring themes related to the subject and its development areas. On the basis of these insights, a digital conceptual model was developed to visualise selected climate adaptation methods identified in the literature review. The model was also complemented by a solar study, which was used to demonstrate variations in access to light and shade throughout the year. A digital workshop was conducted with representatives from the municipalities involved, in which the model, the solar study, and the themes of the literature review formed the basis for a discussion session with a semi structured format. The purpose of the workshop was to establish a clearer anchoring with the selected municipalities, while also supplementing the research based themes and models of the study with practical experience. The results show the significance of microclimate factors, such as wind and access to natural sunlight, for perceived outdoor comfort and thereby for the conditions that enable a pleasant urban life in Norrbotten. The study also demonstrates how blue and green elements can contribute to the pursuit of climate adapted cities, while simultaneously supporting and promoting social values by creating safe and inviting urban environments. In conclusion, the study as a whole indicates how the combination of academic research, visualisation methods, and municipal dialogue can make climate related issues more concrete and easier to discuss already within planning processes
Instantaneous thermally-driven erosion can explain dearth of dark near-Sun asteroids
No full textRecent models of the near-Earth asteroid population show that asteroids must be super-catastrophically destroyed when they evolve to orbits with perihelion passages well inside of Mercury’s orbit. The heliocentric distances at which the disruptions typically occur are tens of solar radii, which is too far from the Sun for asteroids to be destroyed by sublimation and tidal disruption. The typical disruption distance also appears to be larger for darker asteroids. Here, by carrying out irradiance experiments in vacuum that replicate the conditions in the near-Sun environment, we show that CI meteorite simulants are destroyed within minutes when exposed to the level of solar irradiance encountered at heliocentric distances of up to about 0.2 au. Our results provide an explanation for the scarcity of dark, carbonaceous asteroids with perihelion distances less than 0.2 au, and for the observed mass-loss rate of the asteroid-like object 322P/SOHO 1 assuming its composition is similar to CI carbonaceous chondrites.Full text license: CC BY</p
Simultaneous Probe of the Charm and Bottom Quark Yukawa Couplings Using ¯ Events
No full textA search for the standard model Higgs boson decaying to a charm quark-antiquark pair, →¯, produced in association with a top quark-antiquark pair (¯) is presented. The search is performed with data from proton-proton collisions at √ =13 TeV, corresponding to an integrated luminosity of 138 fb−1. Advanced machine learning techniques are employed for jet flavor identification and event classification. The Higgs boson decay to a bottom quark-antiquark pair is measured simultaneously and the observed ¯(→¯) event rate relative to the standard model expectation is 0.91+0.26−0.22. The observed (expected) upper limit on the product of production cross section and branching fraction (¯)ℬ(→¯) is 0.11 (0.13) pb at 95% confidence level, corresponding to 7.8 (8.7) times the standard model prediction. When combined with the previous search for →¯ via associated production with a or boson, the observed (expected) 95% confidence interval on the Higgs-charm Yukawa coupling modifier, , is || <3.5 (2.7), the most stringent constraint to date.Full text license: CC BY</p
Modelling Dynamic Flow Conditions for Fish Habitats in Regulated Rivers
No full textHydropower is an important renewable energy source providing flexible operating conditions that balances the increasing intermittent energy from wind- and solar power. Hydropower however, comes with other environmental challenges by altering the ecological conditions in the rivers by presenting flow conditions such as hydropeaking. To fulfill the Swedish Environmental Code and the demand from the European Water Framework directive to achieve good ecological status (GES) for all watercourses, measures to improve the ecology in the river for each hydropower plant must be presented. Investigating potential restoration measures might be both costly and time-consuming as they are often specific to the site and species involved. Hydraulic modelling of flow conditions connected with individual-based models (IBMs) to evaluate fish population growth, and behaviour, is one way to make these estimations more cost- and time-efficient. The aim of this thesis is to investigate how the results of hydraulic models can be used with IBM’s and how different assumptions in the modelling process could create deviations that could further propagate into the IBM’s. A 2D hydraulic model over a regulated river in northern Sweden is presented where the restoration focus is improving European grayling habitat. As a first step, paper A investigates how modelling parameters could influence the hydrodynamics in the river, and in turn impact the habitat estimations. The results shows that the Neumann boundary conditions are more sensitive to Manning roughness than fixed water level boundaries, especially near upstream and downstream enclosure areas. A fixed water level boundary with velocity measurements at the inlet and outlet can minimize boundary effects on roughness calibration. Careful selection of roughness distribution areas, particularly in high-velocity zones, is crucial as it impacts bed shear stress, and velocities, which can be used for estimating feasible habitat. A gradual roughness transition between calibration areas may improve model accuracy. In a second step, paper B compares a steady-state interpolation method with transient simulations since the IBM implements steady-state simulations of different constant flows to interpolate the depth and velocities across the river for different discharge hydrographs. The goal was to assess how the limitations of a steady-state approach impact different parameters in the IBM’s and how this could affect the long-term habitat. Steady-state and transient simulations were compared, focusing on WSE, spawning habitat and bed shear stress. Steady-state models failed to capture temporal dynamics caused by neglect of time displacement and damping by assuming uniform response times across the river. The bed shear stress was under-predicted by the steady-state interpolation which could lead to inaccurate estimations of suitable spawning grounds and also, the risk of redd scouring. Uncertainties in the depths and velocities over time from the hydraulic model could propagate further in the IBM’s causing the long-term evaluation of fish population to be inaccurate especially when the flow conditions are highly varying during the years where a transient model is preferred. Finally, paper C investigates how the dynamic flow conditions effect the bed shear stress. When no substrate data over the riverbed is available, the bed shear stress can serve as a substitute for identifying suitable spawning areas as input for the IBM. The paper presents the hydraulic conditions in the river during a period of 2 months between May and July to capture the spring flood together with some hydropeaking events during summer. The spawning grounds considering depths and velocities were presented with the maximum bed shear stress during the time period to identify and evaluate possible restoration areas. To evaluate the stability of different spawning gravels used for restoration, the Wilcock-Crowe bedload transport model was implemented in the model. The erosion and sedimentation of the added spawning gravel followed the maximum bed shear stress curves. The results can be used further to evaluate different restoration measures together with the fish population growth with IBM
Finite Element-Based Investigation of Rotor-Bearing-Stator Dynamics
No full textRotating machinery forms the backbone of modern energy conversion, facilitating the transfer of energy between a fluid and a rotating component, the rotor. Mathematical modeling of rotating machinery has become increasingly sophisticated due to growing demands in modern machine design, primarily driven by the increase of angular momentum sustained by the rotor. Thus, the study of rotating machine dynamics has evolved to improve prediction accuracy and ensure operational stability. A rotor typically consists of shafts, disks, and blades, supported by bearings that enable rotation relative to a stationary structure. Bearings are tasked to provide both support and energy dissipation. While rotor-bearing models often suffice for dynamic analysis of rotating machinery, stators—such as casings, housings, and foundations—can influence dynamics through rotor-stator interactions. For example, compliant bearing supports may impair bearing function, while generator stators exert significant electromagnetic forces that impact operational stability. The integrated model of these components is known as a rotor-bearing-stator (RBS) system. While traditional rotor dynamic analysis typically utilizes shaft elements to model the rotor assembly and reduces the stator and bearing to discrete spring elements, a full three-dimensional representation overcomes the kinematic and geometric restrictions of beam theory, enabling the analysis of vastly more complex systems. Furthermore, the increased degrees of freedom lead to greater computational complexity, particularly noticeable for vertical machinery. Unlike horizontal rotors, vertical systems inherently experience large dynamic displacements and lack a stationary point of operation, necessitating the use of nonlinear bearing formulations. Hydropower machinery is generally supported by hydrodynamic journal bearings. This requires tracking the rotor position at each time step and solving equations for fluid-film interaction, further increasing computational demands. This compilation thesis investigates the dynamics of integrated hydropower systems, with emphasis on how to accurately and efficiently model complex, vertical systems by finite element methods. The thesis constitutes three applied studies of vertical RBS-systems, mostly related to hydropower applications. The first paper focuses on a three-dimensional model of a floating-rim synchronous generator, with emphasis on deformation under electromagnetic and centrifugal loads. The second paper explores the interaction between tilting pad journal bearings and an elastic support frame, exploring the potential implementation of nonlinear journal bearing formulations within a three-dimensional finite element framework. Finally, the third paper investigates the impact of a compliant generator-bearing support on the stability of a hydropower rotor-bearing system
Promoting construction innovation : A public infrastructure client’s adaptation of procurement and project management strategies
No full textThe construction and infrastructure sector is a significant contributor to global carbon emissions, necessitating substantial changes to support, what can be called, the sustainability transition. Public infrastructure clients are expected to lead this transition by promoting construction innovation, while engineering consultants, involved in the planning and design of projects, play a key role in supporting these efforts. Public procurement is widely recognized – politically – as a key strategic tool for promoting innovation and advancing sustainability, despite the project-based sector the role of project management remains largely overlooked. However, previous research highlights the importance of both procurement and project management strategies in promoting construction innovation. To effectively promote innovation, these strategies must be adapted to the specific characteristics of each project and should emphasize flexibility and involvement of actors. Despite the procurement and project management strategies’ acknowledged significance, they are often treated as separate governance mechanisms within previous research, failing to account for their interconnected nature. The purpose of this thesis is to increase the understanding of how a public infrastructure client promotes innovation towards the sustainability transition through adaptation of procurement and project management strategies in planning and design of new infrastructure. A longitudinal single-case study of the largest public infrastructure client in Sweden, the Swedish Transport Administration (Trafikverket), provides empirical insights. The findings show that despite high expectations for public clients to promote innovation – especially in designated pilot projects – these projects are evaluated and managed through conventional linear processes, short-term goals, and paradigms. While innovation is acknowledged as a multidimensional concept requiring flexibility and collaboration, procurement and project management strategies remain predominantly control-oriented, emphasizing efficiency, problem-solving, and monitoring. This approach is found to limit the perceived promotion and impact of construction innovation in practice. By problematizing the concept of comprehensive governance – integrating procurement and project management – this thesis highlights how public clients’ reliance on detailed process control and the aligning with a hard paradigm, which is not well-suited to promote construction innovation. The research underscores the interdependence of procurement and project management strategies, advocating for a holistic governance perspective in construction management research and practice. Addressing this interconnection, both within research and practice, is crucial for developing strategies that effectively promotes construction innovation supporting the sustainability transition in public infrastructure projects
Promoting a Sustainable Digital Work Life for People with Cognitive Difficulties
No full textThe digitalization has changed the work life and created new cognitive demands that can be challenging to manage in digital work and everyday life for people with cognitive difficulties related to neurological disorders. Nevertheless, the consequences of these changes are largely unexplored. Thus, the overall aim of this thesis is to enhance knowledge of how people with cognitive difficulties experience digital work and other occupations in everyday life, and how to promote a sustainable digital work life. The thesis comprises four qualitative studies. Study I explored and described how people with cognitive difficulties engaged in digital work, experienced their vocational situation and how it influenced their everyday life. This study was designed as a qualitative, descriptive, multiple case study. Data were collected through semi-structured interviews, self-reports and assessments from seven participants with neurological disorders and analysed using pattern matching. The findings suggest that performing digital work was cognitively demanding and influenced engagement in other valuable occupations. Work-related obligations were prioritized over other occupations in everyday life. Additionally, digital work was facilitated by support from employers and family, as well as by using self-initiated management strategies in challenging situations. Study II described how people with cognitive difficulties due to neurological disorders experienced their use of self-initiated strategies to manage digitalized work and other occupations in everyday life. Eleven participants participated in qualitative interviews, supported by a dialogue support tool. The findings of the qualitative content analysis imply that self-initiated management strategies were often crucial for managing challenging situations in digital work and to uphold engagement in occupations outside work. Having an ability to self-evaluate and reflect upon the use of strategies was necessary for a conscious, flexible and effective use. Study III described employer representatives’ experiences of work environment management focusing on employees with cognitive difficulties working in a digital environment. Focus group discussions with six employer representatives were utilised for data collection. The focus group analysis indicated that aligning the work abilities of employees with cognitive difficulties to the evolving cognitive demands of digital work, was a continuous process. Given the dynamic nature of both employee’s abilities and work demands, fostering a trustful relationship and collaboration with the employee was crucial. This ongoing process required knowledge of digital technologies, the impact of cognitive difficulties on work ability and support from and collaboration with other professionals with related expertise. Study IV, explored and described how an internet-based occupational therapy intervention can support self-management in people with cognitive difficulties performing digital work and other occupations in everyday life. The study was designed as a qualitative, descriptive, case study. Data were collected at three occasions from four people with neurological disorders participating in the intervention ”Strategies for Empowering activities in Everyday life” [SEE 2.0.]. Data gathered through semi-structured interviews, self-reports and assessments were analysed using pattern matching. The findings suggest that SEE 2.0 has the potential to support the development of self-management and initiate a process of change in people with cognitive difficulties, thus having the possibility to facilitate a sustainable digital work and everyday life. The enhanced understanding derived from this thesis can be used to develop vocational rehabilitation for people with cognitive difficulties in digital work. Taking a wider approach when evaluating and identifying cognitive difficulties and considering work and other occupations as an entirety rather than separate parts, is vital. This to facilitate sustained engagement in digital work and a balanced everyday life. It is also essential to have continuous supportive collaboration between employees and employers, as abilities and demands are in constant interaction and change in digital work. Finally, the thesis emphasizes the importance of utilising each person's own resources and strategies to empower self-management, to promote a sustainable digital work life
Micro Transactions and Automation of Industrial Assembly Planning
No full textThis thesis discusses two subjects: distributed ledgers scalable enough to support micro-transactions, and automating assembly planning in manufacturing industries. Established blockchain solutions achieve high robustness and reliability. By being distributed and decentralized, they avoid a single point of failure, and fault-tolerant consensus mechanisms ensure that the system works as intended in the presence of malicious participants. However, their main weakness is scalability. The two most popular and well-known blockchain solutions require all nodes to store all transactions, and the transaction throughput is far too low to compete with traditional, centralized transaction processing systems. To improve scalability, systems have been developed that split the network nodes into groups that can process transactions in parallel, also known as sharding. We propose a novel approach to sharding, called ScaleGraph, which uses concepts from distributed hash tables to define shards dynamically. Nodes store and validate only transactions involving those accounts that are close to the node according to a logical distance metric. This greatly reduces the storage burden on each node and allows any number of transactions involving distinct accounts to be validated in parallel. By employing a synchronous consensus protocol, shards can be kept smaller without sacrificing fault tolerance, especially in a permissioned environment where participation can be controlled and a small fraction of malicious nodes can be assumed. Manufacturing is a highly complex process in many industries, involving many different planning problems, and increasing automation has the potential to make manufacturing more efficient. This thesis presents a proof-of-concept solution to the kitting layout planning problem, where a list of parts has to be placed on a kitting wagon for delivery to an assembly line station. However, some problems have proven difficult to automate in practice, despite decades of research. One such problem, assembly line balancing, is analyzed in depth. We identify fundamental challenges that make the goal of complete automation implausible in some industries, such as automotive manufacturing. Human intervention is thus unavoidable, suggesting that assisted planning is a more promising approach for achieving increased automation in practice. Therefore, we make the case that bridging the gap between theory and practice requires decision-support systems that enable an iterative and interactive workflow