2,177 research outputs found
D3P : Data-driven demand prediction for fast expanding electric vehicle sharing systems
The future of urban mobility is expected to be shared and electric. It is not only a more sustainable paradigm that can reduce emissions, but can also bring societal benefits by offering a more affordable on-demand mobility option to the general public. Many car sharing service providers as well as automobile manufacturers are entering the competition by expanding both their EV fleets and renting/returning station networks, aiming to seize a share of the market and to bring car sharing to the zero emissions level. During their fast expansion, one determinant for success is the ability of predicting the demand of stations as the entire system is growing continuously. There are several challenges in this demand prediction problem: First, unlike most of the existing work which predicts demand only for static systems or at few stages of expansion, in the real world we often need to predict the demand as or even before stations are being deployed or closed, to provide information and decision support. Second, for the new stations to be deployed, there is no historical data available to help the prediction of their demand. Finally, the impact of deploying/closing stations on the other stations in the system can be complex. To address these challenges, we formulate the demand prediction problem in the context of fast expanding electric vehicle sharing systems, and propose a data-driven demand prediction approach which aims to model the expansion dynamics directly from the data. We use a local temporal encoding process to handle the historical data for each existing station, and a dynamic spatial encoding process to take correlations between stations into account with Graph Convolutional Neural Networks (GCN). The encoded features are fed to a multi-scale predictor, which forecasts both the long-term expected demand of the stations and their instant demand in the near future. We evaluate the proposed approach with real-world data collected from a major EV sharing platform for one year. Experimental results demonstrate that our approach significantly outperforms the state of the art, showing up to three-fold performance gain in predicting demand for the expanding EV sharing systems
Securing Cyber-Physical Social Interactions on Wrist-worn Devices
Since ancient Greece, handshaking has been commonly practiced between two people as a friendly gesture to express trust and respect, or form a mutual agreement. In this article, we show that such physical contact can be used to bootstrap secure cyber contact between the smart devices worn by users. The key observation is that during handshaking, although belonged to two different users, the two hands involved in the shaking events are often rigidly connected, and therefore exhibit very similar motion patterns. We propose a novel key generation system, which harvests motion data during user handshaking from the wrist-worn smart devices such as smartwatches or fitness bands, and exploits the matching motion patterns to generate symmetric keys on both parties. The generated keys can be then used to establish a secure communication channel for exchanging data between devices. This provides a much more natural and user-friendly alternative for many applications, e.g., exchanging/sharing contact details, friending on social networks, or even making payments, since it doesn’t involve extra bespoke hardware, nor require the users to perform pre-defined gestures. We implement the proposed key generation system on off-the-shelf smartwatches, and extensive evaluation shows that it can reliably generate 128-bit symmetric keys just after around 1s of handshaking (with success rate >99%), and is resilient to different types of attacks including impersonate mimicking attacks, impersonate passive attacks, or eavesdropping attacks. Specifically, for real-time impersonate mimicking attacks, in our experiments, the Equal Error Rate (EER) is only 1.6% on average. We also show that the proposed key generation system can be extremely lightweight and is able to run in-situ on the resource-constrained smartwatches without incurring excessive resource consumption
Optimal Teleportation Based on Bell Measurement
We study optimal teleportation based on the Bell measurements. An explicit
expression for the quantum channel associated with the optimal teleportation
with an arbitrary mixed state resource is presented. The optimal transmission
fidelity of the corresponding quantum channel is calculated and shown to be
related to the fully entangled fraction of the quantum resource, rather than
the singlet fraction as in the standard teleportation protocol.Comment: 7 pages, latex, no figure
Community Making: An Expansive View of Curriculum
Making as a term has gained attention in the educational field. It signals many different meanings to many different groups, yet is not clearly defined. This project’s researchers refer to making as a term that bears social and cultural impact but with a broader more sociocultural association than definitions that center making in STEM learning. Using the theoretical lenses of critical relationality and embodiment, our research team position curriculum as a set of locally situated activities that are culturally, linguistically, socially, and politically influenced. We argue that curriculum emerges from embodied making experiences in specific interactions with learners and their communities. This study examines multiple ways of learning within and across seven community-based organizations who are engaged directly or indirectly in making activities that embedded literacy, STEM, peace, and the arts. Using online ethnography, the research team adopted a multiple realities perspective that positions curriculum as dynamic, flexible, and evolving based on the needs of a community, its ecosystems, and the wider environment. The research team explored making and curricula through a qualitative analysis of interviews with community organizers and learners. The findings provide thick descriptions of making activities which reconceptualize making and curriculum as living and responsive to community needs. Implications of this study expand and problematize the field’s understanding of making, curriculum, and learning environments
Autonomous learning for face recognition in the wild via ambient wireless cues
Facial recognition is a key enabling component for emerging Internet of Things (IoT) services such as smart homes or responsive offices. Through the use of deep neural networks, facial recognition has achieved excellent performance. However, this is only possibly when trained with hundreds of images of each user in different viewing and lighting conditions. Clearly, this level of effort in enrolment and labelling is impossible for wide-spread deployment and adoption. Inspired by the fact that most people carry smart wireless devices with them, e.g. smartphones, we propose to use this wireless identifier as a supervisory label. This allows us to curate a dataset of facial images that are unique to a certain domain e.g. a set of people in a particular office. This custom corpus can then be used to finetune existing pre-trained models e.g. FaceNet. However, due to the vagaries of wireless propagation in buildings, the supervisory labels are noisy and weak. We propose a novel technique, AutoTune, which learns and refines the association between a face and wireless identifier over time, by increasing the inter-cluster separation and minimizing the intra-cluster distance. Through extensive experiments with multiple users on two sites, we demonstrate the ability of AutoTune to design an environment-specific, continually evolving facial recognition system with entirely no user effort
Map-enhanced visual taxiway extraction for autonomous taxiing of UAVs
In this paper, a map-enhanced method is proposed for vision-based taxiway
centreline extraction, which is a prerequisite of autonomous visual navigation systems for
unmanned aerial vehicles. Comparing with other sensors, cameras are able to provide richer
information. Consequently, vision based navigations have been intensively studied in the
recent two decades and computer vision techniques are shown to be capable of dealing with
various problems in applications. However, there are signi cant drawbacks associated with
these computer vision techniques that the accuracy and robustness may not meet the required
standard in some application scenarios. In this paper, a taxiway map is incorporated into the
analysis as prior knowledge to improve on the vehicle localisation and vision based centreline
extraction. We develop a map updating algorithm so that the traditional map is able to adapt
to the dynamic environment via Bayesian learning. The developed method is illustrated using
a simulation study
NADiffuSE: Noise-aware Diffusion-based Model for Speech Enhancement
The goal of speech enhancement (SE) is to eliminate the background
interference from the noisy speech signal. Generative models such as diffusion
models (DM) have been applied to the task of SE because of better
generalization in unseen noisy scenes. Technical routes for the DM-based SE
methods can be summarized into three types: task-adapted diffusion process
formulation, generator-plus-conditioner (GPC) structures and the multi-stage
frameworks. We focus on the first two approaches, which are constructed under
the GPC architecture and use the task-adapted diffusion process to better deal
with the real noise. However, the performance of these SE models is limited by
the following issues: (a) Non-Gaussian noise estimation in the task-adapted
diffusion process. (b) Conditional domain bias caused by the weak conditioner
design in the GPC structure. (c) Large amount of residual noise caused by
unreasonable interpolation operations during inference. To solve the above
problems, we propose a noise-aware diffusion-based SE model (NADiffuSE) to
boost the SE performance, where the noise representation is extracted from the
noisy speech signal and introduced as a global conditional information for
estimating the non-Gaussian components. Furthermore, the anchor-based inference
algorithm is employed to achieve a compromise between the speech distortion and
noise residual. In order to mitigate the performance degradation caused by the
conditional domain bias in the GPC framework, we investigate three model
variants, all of which can be viewed as multi-stage SE based on the
preprocessing networks for Mel spectrograms. Experimental results show that
NADiffuSE outperforms other DM-based SE models under the GPC infrastructure.
Audio samples are available at: https://square-of-w.github.io/NADiffuSE-demo/
The First Probable Case of Hereditary Angioedema in Vietnam
Hereditary angioedema (HAE) is rare disorder due to C1-inhibitor deficiency (C1-INH) that are debilitating and may be life-threatening. HAE is a lack of consensus concerning diagnosis, therapy, and management, particularly in Vietnam. In this case report, we report a 40-year-old male patient with typical clinical symptoms and family history but he showed normal C4 level, and we could not measure C1q and C1-INH level. However, the diagnosis of HAE can be made based on typical clinical symptoms and the favorable prophylactic response to danazol treatment. Based on these findings, we suggest that he has type I HAE, although he showed normal C4 level
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