VLDB 2026 Research / reviewers in the wild / expert
Susu Xu
dblp:188/9306
· DBLP profile ↗
21ranked-venue papers
3as first author
16since 2021 · last 2026
0000-0001-7170-648XORCID · corroborated
Domains — the database's venue-derived domains; a paper can count in several
Computer networks · 13 · 3 first-author · 9 since 2021Artificial intelligence and machine learning · 5 · 4 since 2021Databases, data management, data science and information retrieval · 2 · 2 since 2021Human-computer interaction and ubiquitous computing · 1 · 1 since 2021Applied, interdisciplinary, general and emerging computing · 1 · 1 since 2021
| Year | Publication | Venue | Position |
|---|---|---|---|
| 2026 | QUIDS: Quality-Informed Incentive-Driven Multiagent Dispatching System for Mobile CrowdsensingabstractThis paper addresses the challenges of achieving optimal quality of information (QoI) in non-dedicated vehicular mobile crowdsensing (NVMCS) system, where vehicles not originally designed for sensing are leveraged to collect real-time data as they traverse urban environments. These challenges are exacerbated by the interrelated issues of sensing coverage, sensing reliability, and the inherently dynamic nature of participating vehicles. To tackle these challenges, we propose QUIDS, a QUality-informed Incentive-driven multi-agent Dispatching System, which ensures high sensing coverage and sensing reliability under budget constraints in NVMCS systems. QUIDS improves QoI by introducing a novel metric, Aggregated Sensing Quality (ASQ), designed to quantitatively capture the concept of QoI by integrating both sensing coverage and sensing reliability. Moreover, we develop a Mutually Assisted Belief-aware Vehicle Dispatching algorithm that estimates sensing reliability and allocates monetary incentives under uncertain vehicle conditions, thereby further improving ASQ. Evaluation using real-world data collected from a deployed NVMCS system in a metropolitan area demonstrates the effectiveness of QUIDS. The ASQ metric shows a 38% improvement over non-dispatching scenarios and a 10% enhancement over state-of-the-art methods. Additionally, QUIDS reduces reconstruction map errors by 39–74% across various reconstruction algorithms, validating its efficacy in improving QoI within NVMCS systems. Addressing the often-overlooked issue of sensing reliability in existing studies, the QUIDS system leverages non-dedicated vehicles and incorporates a quality-informed incentive-driven dispatching system to jointly optimize sensing coverage and sensing reliability. This enables low-cost, high-quality, and scalable urban environmental monitoring without the need for dedicated sensing infrastructure, and makes the system applicable to diverse smart-city scenarios such as traffic monitoring and environmental sensing. Zuxin Li, Fanhang Man, Xuecheng Chen, Susu Xu, Fan Dang 0001, Chaopeng Hong, Yunhao Liu 0001, Xiao-Ping Zhang 0002, Xinlei Chen |
IEEE Internet Things J. | 5 |
| 2026 | SniffySquad: Patchiness-Aware Gas Source Localization with Multi-Robot CollaborationabstractGas source localization is pivotal for the rapid mitigation of gas leakage disasters, where mobile robots emerge as a promising solution. However, existing methods predominantly schedule robots’ movements based on reactive stimuli or simplified gas plume models. These approaches typically excel in idealized, simulated environments but fall short in real-world gas environments characterized by their patchy distribution. In this work, we introduce SniffySquad , a multi-robot olfaction-based system designed to address the inherent patchiness in gas source localization. SniffySquad incorporates a patchiness-aware active sensing approach that enhances the quality of data collection and estimation. Moreover, it features an innovative collaborative role adaptation strategy to boost the efficiency of source-seeking endeavors. Extensive evaluations demonstrate that our system achieves an increase in the success rate by \(20\%+\) and an improvement in path efficiency by \(30\%+\) , outperforming state-of-the-art gas source localization solutions. Yuhan Cheng, Xuecheng Chen, Haoyang Wang 0012, Jingao Xu, Chaopeng Hong, Susu Xu, Xiao-Ping Zhang 0002, Yunhao Liu 0001, Xinlei Chen |
ACM Trans. Sens. Networks | 7 |
| 2025 | From Perceptions to Decisions: Wildfire Evacuation Decision Prediction with Behavioral Theory-informed LLMsabstractEvacuation decision prediction is critical for efficient and effective wildfire response by helping emergency management anticipate traffic congestion and bottlenecks, allocate resources, and minimize negative impacts.Traditional statistical methods for evacuation decision prediction fail to capture the complex and diverse behavioral logic of different individuals.In this work, for the first time, we introduce FLARE, short for facilitating LLM for advanced reasoning on wildfire evacuation decision prediction, a Large Language Model (LLM)-based framework that integrates behavioral theories and models to streamline the Chain-of-Thought (CoT) reasoning and subsequently integrate with memory-based Reinforcement Learning (RL) module to provide accurate evacuation decision prediction and understanding.Our proposed method addresses the limitations of using existing LLMs for evacuation behavioral predictions, such as limited survey data, mismatching with behavioral theory, conflicting individual preferences, implicit and complex mental states, and intractable mental statebehavior mapping.Experiments on three postwildfire survey datasets show an average of 20.47% performance improvement over traditional theory-informed behavioral models, with strong cross-event generalizability. Ruxiao Chen, Chenguang Wang 0012, Yuran Sun, Xilei Zhao, Susu Xu |
ACL (1) | 5 |
| 2024 | Optimizing Rapid Seismic Building Damage Assessment: Integrating Enhanced Radar Change Detection Maps with Variational Bayesian NetworksabstractAccurate damage estimation after earthquakes is crucial for effective post-disaster response and recovery. However, earthquakes often trigger various additional hazards, such as landslides and liquefaction, making accurate building damage estimation even more challenging. To date, despite significant research efforts, automated, accurate building-specific damage estimation has not been achieved. Our study tackles this challenge. We integrate multi-sourced global building footprints and InSAR coherence-based Change Detection Maps (CDMs) generated by the U.S. Geological Survey (USGS) within a variational causal Bayesian network, providing intricate maps of landslides, liquefaction, and building damage. Our key innovations include: 1) a novel masking strategy for the CDMs, derived from low pre-event mean coherence value and high pre-event coherence standard deviation to eliminate noisy signals in InSAR products induced by irrelevant noise sources (steep slopes, soil moisture and vegetation change, open water, etc.), and 2) variational inference to differentiate potential causes of the changes in InSAR coherence signals, specifically landslides, liquefaction, building damage, and non-hazard changes. Our strategy is critical for enhancing the accuracy of building damage and ground failure assessments, as noise from environmental or human-induced changes can obscure true damage signals. We provide reliable damage identification with attribution to specific causes by focusing on accurate building footprints and improving regional ground failure predictions using the 2023 M6.8 Morocco earthquake to validate our methodology. Our approach enables thorough damage analysis across numerous buildings, with the potential for significantly aiding disaster management and marking a substantial advancement of post-earthquake building damage assessment methods. Xuechun Li, Runyu Gao, Paula M. Bürgi, David Jay Wald, Susu Xu |
IGARSS | 5 |
| 2024 | QUEST: Quality-informed Multi-agent Dispatching System for Optimal Mobile CrowdsensingabstractWe address the challenges in achieving optimal Quality of Information (QoI) for non-dedicated vehicular Mobile Crowdsensing (MCS) systems, by utilizing vehicles not originally designed for sensing purposes to provide real-time data while moving around the city. These challenges include the coupled sensing coverage and sensing reliability, as well as the uncertainty and time-varying vehicle status. To tackle these issues, we propose QUEST, a QUality-informed multi-agEnt diSpaTching system, that ensures high sensing coverage and sensing reliability in non-dedicated vehicular MCS. QUEST optimizes QoI by introducing a novel metric called ASQ (aggregated sensing quality), which considers both sensing coverage and sensing reliability jointly. Additionally, we design a mutual-aided truth discovery dispatching method to estimate sensing reliability and improve ASQ under uncertain vehicle statuses. Real-world data from our deployed MCS system in a metropolis is used for evaluation, demonstrating that QUEST achieves up to 26% higher ASQ improvement, leading to a reduction of reconstruction map errors by 32-65% for different reconstruction algorithms. Zuxin Li, Fanhang Man, Xuecheng Chen, Susu Xu, Fan Dang 0002, Xiao-Ping Zhang 0002, Xinlei Chen |
INFOCOM | 4 |
| 2024 | Multi-Agent Target Pursuit Using Perception Uncertainty-Aware Reinforcement LearningabstractExisting target pursuit systems are able to coordinate a team of mobile agents to capture or intercept unauthorized targets. Multi-agent reinforcement learning (MARL) further empowers pursuit strategies with the potential to emerge complex behaviors. However, existing solutions lack the ability to handle the perception uncertainty caused by relative position measurement noises, which blurs the understanding of the target's state and complicates the pursuit strategy learning process. This study proposes PUARL, which enhances the learning under the perception uncertainty process by guiding exploration with probabilistic estimation and adapting the policy based on awareness of perception uncertainty. We validate its performance in terms of both accuracy and efficiency. PUARL achieves a success rate increase of 12.3%+ and a reduction in total steps by 58.3%+, outperforming both state-of-the-art heuristic and learning-based solutions. Yuhan Cheng, Jirong Zha, Renjue Yang, Susu Xu, Xinlei Chen |
MobiCom | 5 |
| 2024 | Preventing Model Collapse in Deep Canonical Correlation Analysis by Noise RegularizationabstractMulti-View Representation Learning (MVRL) aims to learn a unified representation of an object from multi-view data.
Deep Canonical Correlation Analysis (DCCA) and its variants share simple formulations and demonstrate state-of-the-art performance. However, with extensive experiments, we observe the issue of model collapse, i.e., the performance of DCCA-based methods will drop drastically when training proceeds. The model collapse issue could significantly hinder the wide adoption of DCCA-based methods because it is challenging to decide when to early stop. To this end, we develop NR-DCCA, which is equipped with a novel noise regularization approach to prevent model collapse. Theoretical analysis shows that the Correlation Invariant Property is the key to preventing model collapse, and our noise regularization forces the neural network to possess such a property. A framework to construct synthetic data with different common and complementary information is also developed to compare MVRL methods comprehensively. The developed NR-DCCA outperforms baselines stably and consistently in both synthetic and real-world datasets, and the proposed noise regularization approach can also be generalized to other DCCA-based methods such as DGCCA. Junlin He, Jinxiao Du, Susu Xu |
NeurIPS | 3 |
| 2024 | A time-series based deep survival analysis model for failure prediction in urban infrastructure systems
Binyu Yang, Xuanwen Liang, Susu Xu, Man Sing Wong, Wei Ma 0016 |
Eng. Appl. Artif. Intell. | 3 |
| 2024 | SOScheduler: Toward Proactive and Adaptive Wildfire Suppression via Multi-UAV Collaborative SchedulingabstractMulti-UAV systems have shown immense potential in handling complex tasks in large-scale, dynamic, and cold-start (i.e., limited prior knowledge) scenarios, such as wildfire suppression. Due to the dynamic and stochastic environmental conditions, the scheduling for sensing tasks (i.e., fire monitoring) and operation tasks (i.e., fire suppression) should be executed concurrently to enable real-time information collection and timely intervention of the environment. However, the planning inclinations of sensing and operation tasks are typically inconsistent and evolve over time, complicating the task of identifying the optimal strategy for each UAV. To solve this problem, this paper proposes SOScheduler, a collaborative multi-UAV scheduling framework for integrated sensing and operation in large-scale and dynamic wildfire environments. We introduce a spatio-temporal confidence-aware assessment model to dynamically and directly pinpoint locations that can optimally enhance the understanding of environmental dynamics and operational effectiveness, as well as a priority graph-instructed scalable scheduler to coordinate multi-UAV in an efficient manner. Experiments on real multi-UAV testbeds and large-scale physical feature-based simulations show that our SOScheduler reduces the fire expansion ratio by 59% and enhances the fire coverage ratio by 190% compared to state-of-the-art (SOTA) solutions. Xuecheng Chen, Zijian Xiao, Yuhan Cheng, Chen-Chun Hsia, Haoyang Wang 0012, Jingao Xu, Susu Xu, Fan Dang 0001, Xiao-Ping Zhang 0002, Yunhao Liu 0001, Xinlei Chen |
IEEE Internet Things J. | 7 |
| 2023 | DisasterNet: Causal Bayesian Networks with Normalizing Flows for Cascading Hazards Estimation from Satellite ImageryabstractSudden-onset hazards like earthquakes often induce cascading secondary hazards (e.g., landslides, liquefaction, debris flows, etc.) and subsequent impacts (e.g., building and infrastructure damage) that cause catastrophic human and economic losses. Rapid and accurate estimates of these hazards and impacts are critical for timely and effective post-disaster responses. Emerging remote sensing techniques provide pre- and post-event satellite images for rapid hazard estimation. However, hazards and damage often co-occur or colocate with underlying complex cascading geophysical processes, making it challenging to directly differentiate multiple hazards and impacts from satellite imagery using existing single-hazard models. We introduce DisasterNet, a novel family of causal Bayesian networks to model processes that a major hazard triggers cascading hazards and impacts and further jointly induces signal changes in remotely sensed observations. We integrate normalizing flows to effectively model the highly complex causal dependencies in this cascading process. A triplet loss is further designed to leverage prior geophysical knowledge to enhance the identifiability of our highly expressive Bayesian networks. Moreover, a novel stochastic variational inference with normalizing flows is derived to jointly approximate posteriors of multiple unobserved hazards and impacts from noisy remote sensing observations. Integrating with the USGS Prompt Assessment of Global Earthquakes for Response (PAGER) system, our framework is evaluated in recent global earthquake events. Evaluation results show that DisasterNet significantly improves multiple hazard and impact estimation compared to existing USGS products. Xuechun Li, Paula M. Bürgi, Wei Ma 0016, Hae Young Noh, David Jay Wald, Susu Xu |
KDD | 6 |
| 2022 | Discovering and Understanding Algorithmic Biases in Autonomous Pedestrian Trajectory PredictionsabstractPedestrian trajectory prediction is an important module in autonomous vehicles (AVs) to ensure safe and effective motion planning. Recently, many deep learning algorithms that achieve near real-time trajectory predictions have been developed. However, people in the artificial intelligence (AI) ethics community have raised critical concerns about the bias and fairness of many general deep learning algorithms. For example, most pedestrian trajectory data is collected from majority populations, and models learned from this data may not generalize well to the heterogeneous needs and behavior patterns of different pedestrian groups, especially for vulnerable pedestrians like the disabled, the elderly, and children. Biases present in trajectory prediction algorithms could mean that pedestrians from certain vulnerable demographics are more likely to be involved in vehicle crashes. In this work, we test two state-of-the-art pedestrian trajectory prediction models for age and gender biases across three different datasets. We design and utilize novel evaluation metrics for comparing model performance. We find that both models perform worse on children and the elderly compared to adults. However, their performance is similar between men and women. We identify potential sources of these biases, as well as discuss several limitations of our study. Our future work will consist of testing more models, refining our evaluation metrics, further differentiating the dataset bias from the algorithmic bias, and mitigating the algorithmic biases. Andrew Bae, Susu Xu |
SenSys | 2 |
| 2022 | Near-Real-Time Seismic Human Fatality Information Retrieval from Social Media with Few-Shot Large-Language ModelsabstractReal-time disaster-induced human fatality information is critical for rapid and accurate disaster impact and loss estimation and effective emergency response. Systems like PAGER incorporate online reported death tolls and loss projection models trained on significant historical earthquake events and ground shaking data to provide projected final seismic loss estimations. However, the input reported death toll data are mainly retrieved from news platforms manually, which is time-consuming and may have a large time bias. In recent years, platforms such as Facebook and Twitter have become hot spots for witness reporting and communication during disaster events, producing large volumes of immediate fatality information without the hindrances of official channels. Though lucrative, social media data is very noisy both in syntax and accuracy, necessitating robust solutions. In this work, we design and deploy a new online system that automatically extracts near-realtime multi-lingual human fatality information including death tolls and injury tolls, from a variety of information sources immediately after an earthquake occurs. Past studies have proposed to use popular machine learning methods such as SVMs, CNNs and Logistic Regression in conjunction with word embeddings to classify the relevancy of each social media message. However, these techniques suffer from impeding requirements of annotated data, which are unavailable at the onset of natural disasters, and cannot directly extract disaster information, instead relying on statistical analysis on their classification results. To address such challenges, we propose a Large Language Model-based approach that leverages its robust language understanding and few-shot learning abilities. In combination with our novel multilingual Hierarchical Event Classifier, another contribution, we achieve effective automatic earthquake casualty information retrieval from social media, which we test by deploying our framework to two recent earthquakes. James Hou, Susu Xu |
SenSys | 2 |
| 2022 | Riemannian Geometric Instance Filtering for Transfer Learning in Brain-Computer InterfacesabstractDue to the inter-subject variability of Electroencephalogram(EEG) signals, a long calibration time is required to collect a large number of labeled trials to calibrate classifier parameters before using the Brain-computer Interface(BCI). This challenge greatly limits the practical roll-out of BCIs. To address this problem, we propose a novel instance-based transfer learning framework named Riemannian Geometric Instance Filtering (RGIF) to reduce calibration time without sacrificing accuracy. A new inter-subject similarity metric based on Riemannian geometry is proposed to measure the similarity between a few trials from the target subject and adequate trials from source subjects. The classification model for the target subject is then trained with the help of abundant trials from similar source subjects with high similarity to the target subject. We evaluate our method on two open-source EEG datasets. The results show that our approach improves significantly compared with other baselines. Furthermore, compared with using all source subjects data, our method reduces the training time by at least half and achieves slightly better accuracy. Qianxin Hui, Yang Li 0104, Susu Xu, Shuailei Zhang, Ying Sun 0012, Shuai Wang 0049, Xinlei Chen, Dezhi Zheng |
SenSys | 4 |
| 2022 | TCACNet: Temporal and channel attention convolutional network for motor imagery classification of EEG-based BCIabstractBrain–computer interface (BCI) is a promising intelligent healthcare technology to improve human living quality across the lifespan, which enables assistance of movement and communication, rehabilitation of exercise and nerves, monitoring sleep quality, fatigue and emotion. Most BCI systems are based on motor imagery electroencephalogram (MI-EEG) due to its advantages of sensory organs affection, operation at free will and etc. However, MI-EEG classification, a core problem in BCI systems, suffers from two critical challenges: the EEG signal’s temporal non-stationarity and the nonuniform information distribution over different electrode channels. To address these two challenges, this paper proposes TCACNet, a temporal and channel attention convolutional network for MI-EEG classification. TCACNet leverages a novel attention mechanism module and a well-designed network architecture to process the EEG signals. The former enables the TCACNet to pay more attention to signals of task-related time slices and electrode channels, supporting the latter to make accurate classification decisions. We compare the proposed TCACNet with other state-of-the-art deep learning baselines on two open source EEG datasets. Experimental results show that TCACNet achieves 11.4% and 7.9% classification accuracy improvement on two datasets respectively. Additionally, TCACNet achieves the same accuracy as other baselines with about 50% less training data. In terms of classification accuracy and data efficiency, the superiority of the TCACNet over advanced baselines demonstrates its practical value for BCI systems. Rongye Shi, Qianxin Hui, Susu Xu, Shuai Wang 0049, Rui Na, Ying Sun 0012, Wenbo Ding 0001, Dezhi Zheng, Xinlei Chen |
Inf. Process. Manag. | 4 |
| 2022 | Adaptive Hybrid Model-Enabled Sensing System (HMSS) for Mobile Fine-Grained Air Pollution EstimationabstractFine-grained city-scale outdoor air pollution maps provide important environmental information for both city managers and residents. Installing portable sensors on vehicles (e.g., taxis, Ubers) provides a low-cost, easy-maintenance, and high-coverage approach to collecting data for air pollution estimation. However, as non-dedicated platforms, vehicles like taxis usually prefer gathering at busy areas of a city where it is more likely to pick up riders. This leaves many parts of the city unsensed or less-sensed. In addition, due to the natural changes in a city and the movements of the vehicles, the sensed and unsensed areas change over time. Consequently, challenges of air pollution estimation with data collected by non-dedicated mobile platforms are twofold:i.data coverage is sparse;ii.data coverage changes over time. Therefore, the major research question is: how can we derive accurate and robust fine-grained field (e.g., air pollution) estimation given dynamic and sparse data collected from uncontrollable mobile sensing platforms? This paper presents adaptiveHMSS, an adaptivehybridmodel-enabledsensingsystem for fine-grained air pollution estimation with dynamic and sparse data collected from uncontrollable mobile sensing platforms, which is achieved by combining the advantages of aphysics guided modeland adata driven model. To address the challenge of sparse coverage, the physical understanding of the spatiotemporal correlation for air pollution distribution in thephysics guided modelis utilized to infer values at unsensed sparse areas. Meanwhile, thedata driven modelis adopted to estimate the air pollution influential factors (e.g., buildings) not included in thephysics guided model. To address the challenge of time-varying coverage, an adaptive model combination algorithm is designed to enable the system bias to either of the two models according to the amount of data collection and uncertainty of the model. To evaluate the system performance, we deployed 47 air pollution sensing devices on taxis and fixed locations in 2 cities for both controlled and uncontrolled experiments for over two weeks. The results show that with a resolution of$500 \;\mathrm m$by$500\;\mathrm m$by$1\;\mathrm {hour}$, our system achieves up to$3.2\times$error reduction when compared to the baseline approaches. Xinlei Chen, Susu Xu, Xinyu Liu 0003, Xiangxiang Xu 0001, Hae Young Noh, Lin Zhang 0001, Pei Zhang 0001 |
IEEE Trans. Mob. Comput. | 2 |
| 2021 | AutoQual: task-oriented structural vibration sensing quality assessment leveraging co-located mobile sensing contextabstractAbstract In this paper, we introduce AutoQual, a mobile-based assessment scheme for infrastructure sensing task performance prediction under new deployment environments. With the growth of the Internet-of-Things (IoT), many non-intrusive sensing systems have been explored for various indoor applications, such as structural vibration sensing. This indirect sensing approach’s learning performance is prone to deployment variance when signals propagate through the environment. As a result, current systems heavily rely on expert knowledge and manual assessment to achieve effective deployments and high sensing task performance. In order to mitigate this expert effort, we propose to systematically study factors that reflect deployment environment characteristics and methods to measure them autonomously. We present AutoQual that measures a series of assessment factors (AFs) reflecting how the deployment environment impacts the system performance. AutoQual outputs a task-oriented sensing quality (TSQ) score by integrating measured AFs trained from known deployments as a prediction of untested system’s performance. In addition, AutoQual achieves this assessment without manual effort by leveraging co-located mobile sensing context to extract structural vibration signal for processing automatically. We evaluate AutoQual by using it to predict untested systems’ performance over multiple sensing tasks. We conduct real-world experiments and investigate 48 deployments in 11 environments. AutoQual achieves less than 0.10 average absolute error when auto-assessing multiple tasks at untested deployments, which shows a $$\le 0.018$$ ≤ 0.018 absolute error difference compared to the manual assessment approach. Yue Zhang 0044, Zhizhang Hu, Susu Xu, Shijia Pan |
CCF Trans. Pervasive Comput. Interact. | 3 |
| 2020 | PAS: Prediction-Based Actuation System for City-Scale Ridesharing Vehicular Mobile CrowdsensingabstractVehicular mobile crowdsensing (MCS) enables many smart city applications. Ridesharing vehicle fleets provide promising solutions to MCS due to the advantages of low cost, easy maintenance, high mobility, and long operational time. However, as nondedicated mobile sensing platforms, the first priorities of these vehicles are delivering passengers, which may lead to poor sensing coverage quality. Therefore, to help MCS derive good (large and balanced) sensing coverage quality, an actuation system is required to dispatch vehicles with a limited amount of monetary budget. This article presents PAS, a prediction-based actuation system for city-wide ridesharing vehicular MCS to achieve optimal sensing coverage quality with a limited budget. In PAS, two prediction models forecast probabilities of potential near-future vehicle routes and ride requests across the city. Based on prediction results, a prediction-based actuation planning algorithm is proposed to decide which vehicles to actuate and the corresponding routes. Experiments on city-scale deployments and physical feature-based simulations show that our PAS achieves up to 40% more improvement in sensing coverage quality and up to 20% higher ride request matching rate than baselines. In addition, to achieve a similar level of sensing coverage quality as the baseline, our PAS only needs 10% budget. Xinlei Chen, Susu Xu, Jun Han 0001, Haohao Fu, Xidong Pi, Carlee Joe-Wong, Yong Li 0008, Lin Zhang 0001, Hae Young Noh, Pei Zhang 0001 |
IEEE Internet Things J. | 2 |
| 2020 | iLOCuS: Incentivizing Vehicle Mobility to Optimize Sensing Distribution in Crowd SensingabstractVehicular crowd sensing systems are designed to achieve large spatio-temporal sensing coverage with low-cost in deployment and maintenance. For example, taxi platforms can be utilized for sensing city-wide air quality. However, the goals of vehicle agents are often inconsistent with the goal of the crowdsourcer. Vehicle agents like taxis prioritize searching for passenger ride requests (defined as task requests), which leads them to gather in busy regions. In contrast, sensing systems often need to sample data over the entire city with a desired distribution (e.g., Uniform distribution, Gaussian Mixture distribution, etc.) to ensure sufficient spatio-temporal information for further analysis. This inconsistency decreases the sensing coverage quality and thus impairs the quality of the collected information. A simple approach to reduce the inconsistency is to greedily incentivize the vehicle agents to different regions. However, incentivization brings challenges, including the heterogeneity of desired target distributions, limited budget to incentivize more vehicle agents, and the high computational complexity of optimizing incentivizing strategies. To this end, we present a vehicular crowd sensing system to efficiently incentivize the vehicle agents to match the sensing distribution of the sampled data to the desired target distribution with a limited budget. To make the system flexible to various desired target distributions, we formulate the incentivizing problem as a new type of non-linear multiple-choice knapsack problem, with the dissimilarity between the collected data distribution and the desired distribution as the objective function. To utilize the budget efficiently, we design a customized incentive by combining monetary incentives and potential task (ride) requests at the destination. Meanwhile, an efficient optimization algorithm, iLOCuS, is presented to plan the incentivizing policy for vehicle agents to decompose the sensing distribution into two distinct levels: time-location level and vehicle level, to approximate the optimal solution iteratively and reduce the dissimilarity objective. Our experimental results based on real-world data show that our system can reduce up to 26.99 percent of the dissimilarity between the sensed and target distributions compared to benchmark methods. Susu Xu, Xinlei Chen, Xidong Pi, Carlee Joe-Wong, Pei Zhang 0001, Hae Young Noh |
IEEE Trans. Mob. Comput. | 1 |
| 2019 | Vehicle dispatching for sensing coverage optimization in mobile crowdsensing systems: poster abstractabstractMobile crowd sensing (MCS) collects city-scale sensing data with low cost and high efficiency. One important goal of MCS is to ensure high quality of sensing coverage to provide sufficient information to data analysis end. However, the goal of the MCS may be inconsistent with the goal of vehicles. This inconsistency between goals results in a bad sensing coverage and decreases the quality of the collected information. Key challenges to resolve this inconsistency include the heterogeneous target desired spatio-temporal distributions, limited budget constraining the ability to incentivize more taxis, and high computational complexity. Susu Xu, Xinlei Chen, Xidong Pi, Carlee Joe-Wong, Pei Zhang 0001, Hae Young Noh |
IPSN | 1 |
| 2018 | MedAL: Accurate and Robust Deep Active Learning for Medical Image AnalysisabstractDeep learning models have been successfully used in medical image analysis problems but they require a large amount of labeled images to obtain good performance. However, such large labeled datasets are costly to acquire. Active learning techniques can be used to minimize the number of required training labels while maximizing the model's performance. In this work, we propose a novel sampling method that queries the unlabeled examples that maximize the average distance to all training set examples in a learned feature space. We then extend our sampling method to define a better initial training set, without the need for a trained model, by using Oriented FAST and Rotated BRIEF (ORB) feature descriptors. We validate MedAL on 3 medical image datasets and show that our method is robust to different dataset properties. MedAL is also efficient, achieving 80% accuracy on the task of Diabetic Retinopathy detection using only 425 labeled images, corresponding to a 32% reduction in the number of required labeled examples compared to the standard uncertainty sampling technique, and a 40% reduction compared to random sampling. Asim Smailagic, Pedro Costa 0005, Hae Young Noh, Devesh Walawalkar, Kartik Khandelwal, Adrian Galdran, Mostafa Mirshekari, Jonathon Fagert, Susu Xu, Pei Zhang 0001, Aurélio J. C. Campilho |
ICMLA | 9 |
| 2016 | An Indirect Traffic Monitoring Approach Using Building Vibration Sensing System: Poster AbstractabstractNo abstract available. Susu Xu, Lin Zhang 0001, Pei Zhang 0001, Hae Young Noh |
SenSys | 1 |