We present a novel hierarchical model for human activity recognition. In contrast with approaches that successively recognize actions and activities, our approach jointly models actions and activities in a unified framework, and their labels are simultaneously predicted. The model is embedded with a latent layer that is able to capture a richer class of contextual information in both state-state and observation-state pairs. Although loops are present in the model, the model has an overall linear-chain structure, where the exact inference is tractable. Therefore, the model is very efficient in both inference and learning. The parameters of the graphical model are learned with a structured support vector machine. A data-driven approach is used to initialize the latent variables; therefore, no manual labeling for the latent states is required. The experimental results from using two benchmark datasets show that our model outperforms the state-of-the-art approach, and our model is computationally more efficient.
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Vertical urbanisation is perceived as necessary to accommodate a growing population but is associated with severe risks for human well-being. It requires a profound understanding of how archi-tectural designs can ensure visually readable and liveable environments before it has been built. How-ever, current digital representation techniques fail to address the diverse interests of non-experts. Emerging biometric technologies may deliver the missing user information to involve (future) inhabit-ants at different stages of the planning process. The study aims to gain insight into how non-experts (visually) experience 3D city visualizations of designed urban areas. In two laboratory studies, univer-sity students were randomly assigned to view a set of the same level of detail images from one of two planned urban area developments in the Netherlands. Using eye-tracking technology, the visual behav-iour metrics of fixation count and duration and general eye-movement patterns were recorded for each image, followed by a short survey. The results show how visual behaviour and perception are remark-ably similar across different detail levels, implying that 3D visualizations of planned urban develop-ments can be examined by non-experts much earlier in the design process than previously thought.
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The use of machine learning in embedded systems is an interesting topic, especially with the growth in popularity of the Internet of Things (IoT). The capacity of a system, such as a robot, to self-localize, is a fundamental skill for its navigation and decision-making processes. This work focuses on the feasibility of using machine learning in a Raspberry Pi 4 Model B, solving the localization problem using images and fiducial markers (ArUco markers) in the context of the RobotAtFactory 4.0 competition. The approaches were validated using a realistically simulated scenario. Three algorithms were tested, and all were shown to be a good solution for a limited amount of data. Results also show that when the amount of data grows, only Multi-Layer Perception (MLP) is feasible for the embedded application due to the required training time and the resulting size of the model.
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