154092 research outputs found
Sort by
A zone-based Wi-Fi fingerprinting indoor positioning system for factory noise mapping
No full textIndoor positioning systems (IPS) enable the tracking of assets, people, and processes, forming a foundation for smart factory operations. Ultra-wideband positioning offers high accuracy but comes at a significant cost. In contrast, low-cost Wi-Fi fingerprinting offers meter-level accuracy, but its use in industrial environments with poor network infrastructure is limited. Factory layouts are typically structured in zones, making zone-based Wi-Fi fingerprinting feasible to apply. However, fingerprinting is highly sensitive to environmental factors, making it challenging to apply in complicated factory settings. To address these, this study proposes a comprehensive analysis pipeline based on a zone-based IPS architecture, utilizing machine learning models to evaluate the system configuration and zone-related factors for system implementation. In the case study, the zone-based IPS was integrated with a noise map that visualized the real-time noise distribution and tracked object movement in a factory. Two dynamic noise maps demonstrate a hitting rate exceeding 70% for the practical inspection trajectory. This method, which only relies on low-cost Wi-Fi routers and antennas, provides a feasible solution for indoor localization in manufacturing settings, offering a practical and cost-effective alternative IPS.</p
Aerial Robots Carrying Flexible Cables:Dynamic Shape Optimal Control via Spectral Method Model
No full textIn this work, we present a model-based optimal boundary control design for an aerial robotic system composed of a quadrotor carrying a flexible cable. The whole system is modeled by partial differential equations combined with boundary conditions described by ordinary differential equations. The proper orthogonal decomposition (POD) method is adopted to project the original infinite-dimensional system on a finite low-dimensional space spanned by orthogonal basis functions. Based on such a reduced-order model, nonlinear model predictive control is implemented online to realize both position and shape trajectory tracking of the flexible cable in an optimal predictive fashion. The proposed POD-based reduced modeling and optimal control paradigms are verified in simulation using an accurate high-dimensional finite difference method-based model and experimentally using a real quadrotor and a cable. The results show the viability of the POD-based predictive control approach (allowing to close the control loop on the full system state) and its superior performance compared to an optimally tuned proportional–integral–derivative (PID) controller (allowing to close the control loop on the quadrotor state only).</p
On the Thermal Degradation of Lubricant Grease: Experiments
No full textThis study assesses the thermal aging of lubricant grease via five rheological, mechanical, and thermal grease properties—yield stress, storage modulus, bleed capacity, specific heat capacity, and thermal strain coefficient. Three different grease types are studied: a polyurea-thickened grease with fully synthetic ester base oil, and two lithium-thickened greases, one with a mineral base oil and the other with a semi-synthetic base oil. The properties are measured at intervals as the grease samples aged for 30 days in a vacuum oven at 130∘C. The evaporation of base oil and volatiles, which affects the grease properties, is also measured. Results show inconsistent changes in the properties throughout the aging process, with the most significant transformations occurring in the first 10 days—during which most of the evaporation occurred. In addition to evaporation, other mechanisms appear active. Various levels of discolorations are observed. About 0.5thickened grease is lost to evaporation, and about 5thickened greases evaporates. Results from a separate thermogravimetric test show that the fully synthetic ester base oil bled from the polyurea grease has the highest latent heat of evaporation of 337.9 kJ/kg, while the mineral and semi-synthetic base oils bled from the lithium greases have comparable latent heats of evaporation of 154 kJ/kg and 137.7 kJ/kg, respectively
Handmatige Layout Analyse NL-ZlHCO0003.1 (Collectie Overijssel - Resoluties van de Staten van Overijssel)
No full textNL-ZlHCO0003.1 bestaat uit 118 banden, en daarbinnen is een grote variatie aan layout aanwezig. Middels een inventarisatie (visueel) is een overzicht gemaakt van de layout
Biodiverse and spatially self-organized tidal marshes are most effective for nature-based shoreline protection
No full textIntroduction: Coastal flood protection faces growing challenges due to sea level rise and intensifying storms driven by climate change. Conservation or creation of tidalmarshes offers a promising nature-based adaptation for protection of muddy estuarine shorelines against erosion and flood risks, as they attenuate wave impacts while providing ecological benefits [1], [2], [3]. However, limited knowledge exists on how much the efficiency of nature-based wave attenuation depends on (a) biodiversity, i.e. the presence of multiple plant species with species-specific plant-wave interactions, and (b) resulting self-organization of spatial zonation of plant species. This study investigates this question, focusing on tidal marsh species commonly found in NW European estuaries.<br/
Unveiling pervasive assumptions:moving beyond the poverty-biodiversity loss association in conservation
No full textThis paper reflects on the continued persistence of the idea in conservation research and practice that poverty drives biodiversity loss (the poverty-biodiversity loss association [PBLA]). We draw on evidence to show how the PBLA has proven resistant to counter-evidence and is particularly visible at local-level implementation, and is often implicit in conservation strategies. We untangle three underlying reasons that help to explain why the PBLA has persisted under a verisimilitude (seeming truth) that can leave it hiding in plain sight. In doing so, we offer conservation science and practice the means to recognise and thereby remedy this thinking where it exists, and in so doing, advance conservation towards its aims of equitable and effective delivery. We outline how the Connected Conservation model may be better equipped to challenge the disproportionate role of wealth in biodiversity decline whilst empowering biodiversity stewards and their plural knowledge, values and governance systems.</p
Older people’s participation in responsible research and innovation. A qualitative study on motivation
No full textUser inclusion in innovation is vital, yet poorly executed, especially for vulnerable groups like older adults. The demographic shift increases the need for innovation, particularly in the healthcare sector. To ensure innovation meets, the needs of older people, they should be included earlier and with more influence. However, barriers to this participation exist, with motivation often overlooked in research. Our study examined user panels from two European innovation intermediaries to understand how older people's motivation evolves during innovation. Between 2020 and 2022, we conducted 28 interviews, nine open-ended questionnaires, and two focus groups. Our findings reveal that motivation varies before, during, and after inclusion. Key themes include that shared ownership of the innovation process can be motivating but also creates insecurity. Additionally, the lack of follow-up after sessions diminishes motivation. We conclude that prioritizing motivation is essential for effectively including older adults in innovation.</p
Internet skills, digital engagement, and outcomes among urban youth in Jakarta, Indonesia:incorporating a Global South context in measuring digital inequality
No full textThis article examines internet skills, digital engagement, and digital outcomes among urban youth in Jakarta, Indonesia, thereby addressing the underexplored issue of digital inequality in the Global South. We tested and modified digital inequality scales initially developed in the Global North through cognitive interviews and confirmatory factor analyses. The internet skills scale exhibited a reasonable model fit. The modified digital engagement and outcomes scales demonstrate significantly better model fit than their initial counterparts. Among 1,250 surveyed individuals aged 16–30 in Jakarta, we discovered that, despite being labeled as digital natives, many young people possess only moderate internet skills, limited digital engagement, and average digital outcomes. Furthermore, we investigate the intricate relationships between socioeconomic backgrounds and digital inequalities. We identified stratification in skills, engagement, and outcomes, which were affected by education level and, to a lesser degree, perceived social class and quality of internet access. With the modified versions of the digital engagement and outcomes scales, we aim to develop more inclusive measurement tools that can be utilized across various countries. The modified digital engagement and outcomes scales might still exhibit Western bias and overlook the significance of social priorities common among youth in the Global South. Tackling digital inequality may require providing underprivileged youth with training in internet skills and optimizing internet usage through formal and informal education.</p
Exploring the potential solutions to the criticisms of positive psychology:But can the bold, idealistic visions of positive psychologists survive real-world scrutiny?
No full textPositive psychology has faced growing criticism regarding its scientific foundations and applied impact. To encourage constructive dialog, this study employs a Participatory Action Research (PAR) approach to co-create potential ways to address the critiques of positive psychology. By engaging positive psychological practitioners and scholars, we investigate their perspectives on addressing the discipline’s theoretical, methodological, and practical challenges and critically evaluate the viability of these solutions. Purposive sampling gathered data from 213 positive psychology researchers and practitioners. Participants were familiarized with the main criticisms through a participatory online workshop and then engaged in small group discussions to generate potential solutions to such. Content analysis identified 16 themes and 37 categories of proposed solutions. While the proposed solutions showed promise, some appear idealistic given academic realities. This participatory study empowers positive psychologists to actively shape the evolution of their field through ongoing dialog, reflective co-creation and knowledge generation.</p