611 research outputs found

    Micromachined Artificial Haircell

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    A micromachined artificial sensor comprises a support coupled to and movable with respect to a substrate. A polymer, high-aspect ratio cilia-like structure is disposed on and extends out-of-plane from the support. A strain detector is disposed with respect to the support to detect movement of the support

    Crack Risk Evaluation of Early Age Concrete Based on the Distributed Optical Fiber Temperature Sensing

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    Cracks often appear in concrete arch dams, due to the thermal stress and low tensile strength of early age concrete. There are three commonly used temperature controlling measures: controlling the casting temperature, burying cooling pipe, and protecting the surface. However, because of the difficulty to obtain accurate temperature and thermal stress field of the concrete, the rationality and economy of these measures are not assessed validly before and after construction. In this paper, a crack risk evaluation system for early age concrete is established, including distributed optical fiber temperature sensing (DTS), prediction of temperature and stress fields, and crack risk evaluation. Based on the DTS temperature data, the back-analysis method is applied to retrieve the thermal parameters of concrete. Then, the temperature and thermal stress of early age concrete are predicted using the reversed thermal parameters, as well as the laboratory test parameters. Finally, under the proposed cracking risk evaluation principle, the cracking risk level of each concrete block is given; the preliminary and later temperature controlling measures were recommended, respectively. The application of the proposed system in Xiluodu super high arch dam shows that this system works effectively for preventing cracks of early age concrete

    Locating Mobile Telecommunication Facilities in Extreme Events Evacuation

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    Large regional evacuations caused by severe weather such as hurricane’s and tsunami’s are fraught with complexity, uncertainty and risk. During such events, evacuees have to make decisions on route planning and point-of-destination while emergency managers need to ensure that appropriate personnel and infrastructure are available and capable of facilitating the evacuation. In parallel, the widespread usage of social media and micro-blogs enabled by mobile technology is leading to more dynamic decision-making and real-time communication by evacuees. This research uses deterministic and simulation techniques to model regional hurricane evacuation. A mixed integer formulation for telecommunication equipment location is used to identify gaps or strains in mobile service and to locate mobile telecommunications equipment to temporarily alleviate system stress. This problem unifies location allocation and routing characteristics with signal interference processing to maximize the number of served users through the evacuation. A Greedy Randomized Adaptive Search Procedure (GRASP) metaheuristic and a Lagrangian Relaxation-based heuristic are used to solve larger problem instances. Agent-based simulation modeling is used to investigate the reliability, robustness and effectiveness of telecommunications equipment location given the inherent diversity and uncertainty of individual decision-making during evacuation. The agent-based simulation adopts Fuzzy Cognitive Maps to model individual evacuation decision-making that dynamically integrates external information (e.g., physical environment, interpersonal communication) and internal data (e.g., historical empirical, demographic trends). This research shows how social communication among evacuees positively impacts travel patterns as well as overall evacuation time and the usage of mobile telecommunications equipment

    HFORD: High-Fidelity and Occlusion-Robust De-identification for Face Privacy Protection

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    With the popularity of smart devices and the development of computer vision technology, concerns about face privacy protection are growing. The face de-identification technique is a practical way to solve the identity protection problem. The existing facial de-identification methods have revealed several problems, including the impact on the realism of anonymized results when faced with occlusions and the inability to maintain identity-irrelevant details in anonymized results. We present a High-Fidelity and Occlusion-Robust De-identification (HFORD) method to deal with these issues. This approach can disentangle identities and attributes while preserving image-specific details such as background, facial features (e.g., wrinkles), and lighting, even in occluded scenes. To disentangle the latent codes in the GAN inversion space, we introduce an Identity Disentanglement Module (IDM). This module selects the latent codes that are closely related to the identity. It further separates the latent codes into identity-related codes and attribute-related codes, enabling the network to preserve attributes while only modifying the identity. To ensure the preservation of image details and enhance the network's robustness to occlusions, we propose an Attribute Retention Module (ARM). This module adaptively preserves identity-irrelevant details and facial occlusions and blends them into the generated results in a modulated manner. Extensive experiments show that our method has higher quality, better detail fidelity, and stronger occlusion robustness than other face de-identification methods

    Diff-Privacy: Diffusion-based Face Privacy Protection

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    Privacy protection has become a top priority as the proliferation of AI techniques has led to widespread collection and misuse of personal data. Anonymization and visual identity information hiding are two important facial privacy protection tasks that aim to remove identification characteristics from facial images at the human perception level. However, they have a significant difference in that the former aims to prevent the machine from recognizing correctly, while the latter needs to ensure the accuracy of machine recognition. Therefore, it is difficult to train a model to complete these two tasks simultaneously. In this paper, we unify the task of anonymization and visual identity information hiding and propose a novel face privacy protection method based on diffusion models, dubbed Diff-Privacy. Specifically, we train our proposed multi-scale image inversion module (MSI) to obtain a set of SDM format conditional embeddings of the original image. Based on the conditional embeddings, we design corresponding embedding scheduling strategies and construct different energy functions during the denoising process to achieve anonymization and visual identity information hiding. Extensive experiments have been conducted to validate the effectiveness of our proposed framework in protecting facial privacy.Comment: 17page
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