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"Thomas, Jan"
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Youth, multiculturalism and community cohesion
\"This book discusses the meaning and practice of British community cohesion policies, youth identities in racially-tense areas and the British government's attempts to \"prevent violent extremism\" amongst young Muslims\"-- Provided by publisher.
Book
r.avaflow v1, an advanced open-source computational framework for the propagation and interaction of two-phase mass flows
r.avaflow represents an innovative open-source computational tool for routing rapid mass flows, avalanches, or process chains from a defined release area down an arbitrary topography to a deposition area. In contrast to most existing computational tools, r.avaflow (i) employs a two-phase, interacting solid and fluid mixture model (Pudasaini, 2012); (ii) is suitable for modelling more or less complex process chains and interactions; (iii) explicitly considers both entrainment and stopping with deposition, i.e. the change of the basal topography; (iv) allows for the definition of multiple release masses, and/or hydrographs; and (v) serves with built-in functionalities for validation, parameter optimization, and sensitivity analysis. r.avaflow is freely available as a raster module of the GRASS GIS software, employing the programming languages Python and C along with the statistical software R. We exemplify the functionalities of r.avaflow by means of two sets of computational experiments: (1) generic process chains consisting in bulk mass and hydrograph release into a reservoir with entrainment of the dam and impact downstream; (2) the prehistoric Acheron rock avalanche, New Zealand. The simulation results are generally plausible for (1) and, after the optimization of two key parameters, reasonably in line with the corresponding observations for (2). However, we identify some potential to enhance the analytic and numerical concepts. Further, thorough parameter studies will be necessary in order to make r.avaflow fit for reliable forward simulations of possible future mass flow events.
Journal Article
Reconstruction of the 1941 GLOF process chain at Lake Palcacocha (Cordillera Blanca, Peru)
The Cordillera Blanca in Peru has been the scene of rapid deglaciation for many decades. One of numerous lakes formed in the front of the retreating glaciers is the moraine-dammed Lake Palcacocha, which drained suddenly due to an unknown cause in 1941. The resulting Glacial Lake Outburst Flood (GLOF) led to dam failure and complete drainage of Lake Jircacocha downstream, and to major destruction and thousands of fatalities in the city of Huaráz at a distance of 23 km. We chose an integrated approach to revisit the 1941 event in terms of topographic reconstruction and numerical back-calculation with the GIS-based open-source mass flow/process chain simulation framework r.avaflow, which builds on an enhanced version of the Pudasaini (2012) two-phase flow model. Thereby we consider four scenarios: (A) and (AX) breach of the moraine dam of Lake Palcacocha due to retrogressive erosion, assuming two different fluid characteristics; (B) failure of the moraine dam caused by the impact of a landslide on the lake; and (C) geomechanical failure and collapse of the moraine dam. The simulations largely yield empirically adequate results with physically plausible parameters, taking the documentation of the 1941 event and previous calculations of future scenarios as reference. Most simulation scenarios indicate travel times between 36 and 70 min to reach Huaráz, accompanied with peak discharges above 10 000 m3 s−1. The results of the scenarios indicate that the most likely initiation mechanism would be retrogressive erosion, possibly triggered by a minor impact wave and/or facilitated by a weak stability condition of the moraine dam. However, the involvement of Lake Jircacocha disguises part of the signal of process initiation farther downstream. Predictive simulations of possible future events have to be based on a larger set of back-calculated GLOF process chains, taking into account the expected parameter uncertainties and appropriate strategies to deal with critical threshold effects.
Journal Article
Improving Sewer Damage Inspection: Development of a Deep Learning Integration Concept for a Multi-Sensor System
The maintenance and inspection of sewer pipes are essential to urban infrastructure but remain predominantly manual, resource-intensive, and prone to human error. Advancements in artificial intelligence (AI) and computer vision offer significant potential to automate sewer inspections, improving reliability and reducing costs. However, the existing vision-based inspection robots fail to provide data quality sufficient for training reliable deep learning (DL) models. To address these limitations, we propose a novel multi-sensor robotic system coupled with a DL integration concept. Following a comprehensive review of the current 2D (image) and 3D (point cloud) sewage pipe inspection methods, we identify key limitations and propose a system incorporating a camera array, front camera, and LiDAR sensor to optimise surface capture and enhance data quality. Damage types are assigned to the sensor best suited for their detection and quantification, while tailored DL models are proposed for each sensor type to maximise performance. This approach enables the optimal detection and processing of relevant damage types, achieving higher accuracy for each compared to single-sensor systems.
Journal Article
Fieldwork in modern Chinese history : a research guide
\"This book explores how fieldwork has been used to research Chinese history in the past and new ways that others might use in it the future. It introduces the previous generations of scholars who ventured out of the archive to conduct local investigations in Chinese cities, villages, farms and temples. It goes on to present the techniques of historical fieldwork, providing guidance on how to integrate oral history into research plans and archival research, conduct interviews, and locate sources in the field. Chapters by established researchers relate these techniques to specific types of fieldwork, including religion, the imperial past, natural environments and agriculture. Combining the past and the future of the craft, the book provides a rich resource for scholars coming new to fieldwork in the history of China\"-- Provided by publisher.
Book
Particle trajectories, velocities, accelerations and rotation rates in snow avalanches
Understanding the dynamics of snow avalanches is crucial for predicting their destructive potential and mobility. To gain insight into avalanche dynamics at a particle level, the AvaNode in-flow sensor system was developed. These synthetic particles, equipped with advanced and affordable sensors such as an inertial measurement unit (IMU) and global navigation satellite system (GNSS), travel with the avalanche flow. This study focuses on assessing the feasibility of the in-flow measurement systems. The experiments were conducted during the winter seasons of 2021–2023, both in static snow cover and dynamic avalanche conditions of medium-sized events. Radar measurements were used in conjunction with the particle trajectories and velocities to understand the behaviour of the entire avalanche flow. The dynamic avalanche experiments allowed to identify three distinct particle flow states: (I) initial rapid acceleration, (II) a steady state flow with the highest velocities (9–17 ms−1), and (III) a longer deceleration state accompanied by the largest measured rotation rates. The particles tend to travel towards the tail of the avalanche and reach lower velocities compared to the frontal approach velocities deduced from radar measurements (ranging between 23–28 ms−1). The presented data give a first insight in avalanche particle measurements.
Journal Article
An analysis of usability evaluation practices and contexts of use in wearable robotics
Background
User-centered design approaches have gained attention over the past decade, aiming to tackle the technology acceptance issues of wearable robotic devices to assist, support or augment human capabilities. While there is a consensus that usability is key to user-centered design, dedicated usability evaluation studies are scarce and clear evaluation guidelines are missing. However, the careful consideration and integration of user needs appears to be essential to successfully develop an effective, efficient, and satisfactory human-robot interaction. It is primarily the responsibility of the developer, to ensure that this users involvement takes place throughout the design process.
Methods
Through an online survey for developers of wearable robotics, we wanted to understand how the design and evaluation in actual daily practice compares to what is reported in literature. With a total of 31 questions, we analyzed the most common wearable robotic device applications and their technology maturity, and how these influence usability evaluation practices.
Results
A total of 158 responses from a heterogeneous population were collected and analyzed. The dataset representing contexts of use for augmentation (16.5%), assistance (38.0%), therapy (39.8%), as well as few other specific applications (5.7%), allowed for an insightful analysis of the influence of technology maturity on user involvement and usability evaluation. We identified functionality, ease of use, and performance as the most evaluated usability attributes and could specify which measures are used to assess them. Also, we could underline the frequent use of qualitative measures alongside the expected high prevalence of performance-metrics. In conclusion of the analysis, we derived evaluation recommendations to foster user-centered design and usability evaluation.
Conclusion
This analysis might serve as state-of-the-art comparison and recommendation for usability studies in wearable robotics. We believe that by motivating for more balanced, comparable and user-oriented evaluation practices, we may support the wearable robotics field in tackling the technology acceptance limitations.
Journal Article