In mixed traffic environments that involve conventional vehicles (CVs) and autonomous vehicles (AVs), it is essential for CV drivers to maintain an appropriate level of situation awareness (SA) to ensure safe and efficient interactions with AVs. While previous research has established the benefits of external human–machine interfaces (HMIs) for communicating AV intent, this study extended this knowledge by focusing on the vital but underexplored interaction with CV drivers. Specifically, we investigated how AV communication through HMIs affected CV drivers by systematically comparing internal (iHMI) and external (eHMI) interfaces, and examined their impact on CV driver awareness, cognitive load, and behavior. Initially, we designed eight HMI concepts through a human-centered design process. The two highest-rated concepts were selected for implementation as eHMIs and iHMIs. Subsequently, we designed a within-subjects experiment with three conditions: a control condition without any communication HMI, and two treatment conditions using eHMIs and iHMIs as communication means. We investigated the effects of these conditions on 50 participants in a virtual environment (VR) driving simulator. Self-reported assessments and eye-tracking measures were employed to evaluate participants’ SA, trust, acceptance, and mental workload. Results indicated that the iHMI condition resulted in superior SA among participants and improved trust in the AV compared to the control and eHMI conditions. Additionally, iHMI led to a comparatively lower increase in mental workload compared to the other two conditions. Our study contributes to the development of effective AV-CV communications and has the potential to inform the design of future AV systems.

The problem of robust Sparse Linear Discriminant Analysis (LDA) in high-dimensions is studied, in which a fraction of the training data may be corrupted by an adversary. A computationally efficient algorithm is proposed by adapting robust mean estimation along with a calibration framework for LDA. Theoretical properties of the proposed algorithm are established for both the estimation error of the optimal projection vector and the mis-classification rate. Results from extensive numerical studies on both synthetic and real datasets are reported to show the usefulness of our algorithm.

The problem considered is one of maximizing the information flow through a sensor network tasked with estimating, at a fusion center, an underlying parameter in a linear observation model. The sensor nodes take observations, quantize them, and send them to the fusion center through a network of relay nodes. The links in the network are assumed to satisfy certain capacity constraints in terms of the maximum number of bits that can be transmitted on the links. Furthermore, the relay nodes are assumed to satisfy flow conservation constraints, i.e., the number of bits flowing into a relay node is equal to the number of bits flowing out of it. It is shown that this flow optimization problem for estimation can be cast as a Network Utility Maximization (NUM) problem by suitably defining the utility functions at the sensors. The inference problem considered is one of parameter estimation with a linear observation model, which is studied in both Bayesian and non-Bayesian settings. Upper bounds on the mean-squared error (MSE) of optimal linear estimators are obtained in both settings, and these bounds are used to construct utility functions for the corresponding NUM problems. It is verified via simulations that the bit assignments at the sensors obtained through the solutions to the NUM problems, in both the Bayesian and non-Bayesian settings, yield considerably better estimation performance than the Max-Flow solution that simply assigns bits to the sensors in such a way as to maximize the total bits transmitted to the fusion center.

The problem of robust mean estimation in high dimensions is studied, in which a certain fraction (less than half) of the datapoints can be arbitrarily corrupted. Motivated by compressive sensing, the robust mean estimation problem is formulated as the minimization of the ℓ0-‘norm’ of anoutlier indicator vector, under a second moment constraint on the datapoints. The ℓ0-‘norm’ is then relaxed to the ℓp-norm (0p≤ 1) in the objective, and it is shown that the global minima for each of these objectives are order-optimal and have optimal breakdown point for the robust mean estimation problem. Furthermore, a computationally tractable iterative ℓp-minimization and hard thresholding algorithm is proposed that outputs an order-optimal robust estimate of the population mean. The proposed algorithm (with breakdown point ≈ 0.3) does not require prior knowledge of the fraction of outliers, in contrast with most existing algorithms, and forp= 1 it has near-linear time complexity. Both synthetic and real data experiments demonstrate that the proposed algorithm outperforms state-of-the-art robust mean estimation methods.

Classifying complex human motion sequences is a major research challenge in the domain of human activity recognition. Currently, most popular datasets lack a specialized set of classes pertaining to similar action sequences (in terms of spatial trajectories). To recognize such complex action sequences with high inter-class similarity, such as those in karate, multiple streams are required. To fulfill this need, we propose MS-KARD, a Multi-Stream Karate Action Recognition Dataset that uses multiple vision perspectives, as well as sensor data - accelerometer and gyroscope. It includes 1518 video clips along with their corresponding sensor data. Each video was shot at 30fps and lasts around one minute, equating to a total of 2,814,930 frames and 5,623,734 sensor data samples. The dataset has been collected for 23 classes like Jodan Zuki, Oi Zuki, etc. The data acquisition setting involves the combination of 2 orthogonal web cameras and 3 wearable inertial sensors recording both vision and inertial data respectively. The aim of this dataset is to aid research that deals with recognizing human actions that have similar spatial trajectories. The paper describes statistics of the dataset, acquisition setting, and provides baseline performance figures using popular action recognizers. We propose an ensemble-based method, KarateNet, that performs decision-level fusion on the two input modalities (vision and sensor data) to classify actions. For the first stream, the RGB frames are extracted from the videos and passed into action recognition networks like Temporal Segment Network (TSN) and Temporal Shift Module (TSM). For the second stream, the sensor data is converted into a 2-D image and fed into a Convolutional Neural Network (CNN). The results reported were obtained on performing a fusion of the 2 streams. We also report results on ablations that use fusion with various input settings. The dataset and code will be made publicly available.

The problem of robust mean estimation in high dimensions is studied, in which a certain fraction (less than half) of the datapoints can be arbitrarily corrupted. Motivated by compressive sensing, the robust mean estimation problem is formulated as the minimization of the ℓ0-‘norm’ of an outlier indicator vector, under a second moment constraint on the datapoints. The ℓ0-‘norm’ is then relaxed to the ℓp-norm (0p-minimization and hard thresholding algorithm is proposed that outputs an order-optimal robust estimate of the population mean. The proposed algorithm (with breakdown point ≈0.3) does not require prior knowledge of the fraction of outliers, in contrast with most existing algorithms, and for p = 1 it has near-linear time complexity. Both synthetic and real data experiments demonstrate that the proposed algorithm outperforms state-of-the-art robust mean estimation methods.

The problem of maximizing the information flow through a sensor network tasked with an inference objective at the fusion center is considered. The sensor nodes take observations, compress and send them to the fusion center through a network of relays. The network imposes capacity constraints on the rate of transmission in each connection and flow conservation constraints. It is shown that this rate-constrained inference problem can be cast as a Network Utility Maximization problem by suitably defining the utility functions for each sensor, and can be solved using existing techniques. Two practical settings are analyzed: multi-terminal parameter estimation and binary hypothesis testing. It is verified via simulations that using the proposed formulation gives better inference performance than the Max-Flow solution that simply maximizes the total bit-rate to the fusion center.

The problem of online packet scheduling to minimize the required energy for transmitting a fixed number of packets given a common deadline is considered. The total number of packets arriving within the deadline is known, but the packet arrival times are unknown, and can be arbitrary. The proposed algorithm tries to finish the transmission of each packet assuming all future packets are going to arrive at equal time intervals within the left-over time. The proposed online algorithm is shown to have competitive ratio that is logarithmic in the number of packet arrivals.

The problem of online packet scheduling to minimize the required conventional grid energy for transmitting a fixed number of packets given a common deadline is considered. The total number of packets arriving within the deadline is known, but the packet arrival times are unknown, and can be arbitrary. The proposed algorithm tries to finish the transmission of each packet assuming that all future packets are going to arrive at equal time intervals within the left-over time. The proposed online algorithm is shown to have competitive ratio that is logarithmic in the number of packet arrivals. The hybrid energy paradigm is also considered, where in addition to grid energy, energy is also available via extraction from renewable sources. The objective here is to minimize the grid energy use. A suitably modified version of the previous algorithm is also shown to have competitive ratio that is logarithmic in the number of packet arrivals.