Visible to the public Biblio

Filters: Keyword is crowdsourcing  [Clear All Filters]
2021-03-04
Ghaffaripour, S., Miri, A..  2020.  A Decentralized, Privacy-preserving and Crowdsourcing-based Approach to Medical Research. 2020 IEEE International Conference on Systems, Man, and Cybernetics (SMC). :4510—4515.
Access to data at large scales expedites the progress of research in medical fields. Nevertheless, accessibility to patients' data faces significant challenges on regulatory, organizational and technical levels. In light of this, we present a novel approach based on the crowdsourcing paradigm to solve this data scarcity problem. Utilizing the infrastructure that blockchain provides, our decentralized platform enables researchers to solicit contributions to their well-defined research study from a large crowd of volunteers. Furthermore, to overcome the challenge of breach of privacy and mutual trust, we employed the cryptographic primitive of Zero-knowledge Argument of Knowledge (zk-SNARK). This not only allows participants to make contributions without exposing their privacy-sensitive health data, but also provides a means for a distributed network of users to verify the validity of the contributions in an efficient manner. Finally, since without an incentive mechanism in place, the crowdsourcing platform would be rendered ineffective, we incorporated smart contracts to ensure a fair reciprocal exchange of data for reward between patients and researchers.
2021-01-11
Khadka, A., Argyriou, V., Remagnino, P..  2020.  Accurate Deep Net Crowd Counting for Smart IoT Video acquisition devices. 2020 16th International Conference on Distributed Computing in Sensor Systems (DCOSS). :260—264.

A novel deep neural network is proposed, for accurate and robust crowd counting. Crowd counting is a complex task, as it strongly depends on the deployed camera characteristics and, above all, the scene perspective. Crowd counting is essential in security applications where Internet of Things (IoT) cameras are deployed to help with crowd management tasks. The complexity of a scene varies greatly, and a medium to large scale security system based on IoT cameras must cater for changes in perspective and how people appear from different vantage points. To address this, our deep architecture extracts multi-scale features with a pyramid contextual module to provide long-range contextual information and enlarge the receptive field. Experiments were run on three major crowd counting datasets, to test our proposed method. Results demonstrate our method supersedes the performance of state-of-the-art methods.

2020-12-11
Correia, A., Fonseca, B., Paredes, H., Schneider, D., Jameel, S..  2019.  Development of a Crowd-Powered System Architecture for Knowledge Discovery in Scientific Domains. 2019 IEEE International Conference on Systems, Man and Cybernetics (SMC). :1372—1377.
A substantial amount of work is often overlooked due to the exponential rate of growth in global scientific output across all disciplines. Current approaches for addressing this issue are usually limited in scope and often restrict the possibility of obtaining multidisciplinary views in practice. To tackle this problem, researchers can now leverage an ecosystem of citizens, volunteers and crowd workers to perform complex tasks that are either difficult for humans and machines to solve alone. Motivated by the idea that human crowds and computer algorithms have complementary strengths, we present an approach where the machine will learn from crowd behavior in an iterative way. This approach is embodied in the architecture of SciCrowd, a crowd-powered human-machine hybrid system designed to improve the analysis and processing of large amounts of publication records. To validate the proposal's feasibility, a prototype was developed and an initial evaluation was conducted to measure its robustness and reliability. We conclude this paper with a set of implications for design.
2020-04-20
To, Hien, Shahabi, Cyrus, Xiong, Li.  2018.  Privacy-Preserving Online Task Assignment in Spatial Crowdsourcing with Untrusted Server. 2018 IEEE 34th International Conference on Data Engineering (ICDE). :833–844.
With spatial crowdsourcing (SC), requesters outsource their spatiotemporal tasks (tasks associated with location and time) to a set of workers, who will perform the tasks by physically traveling to the tasks' locations. However, current solutions require the locations of the workers and/or the tasks to be disclosed to untrusted parties (SC server) for effective assignments of tasks to workers. In this paper we propose a framework for assigning tasks to workers in an online manner without compromising the location privacy of workers and tasks. We perturb the locations of both tasks and workers based on geo-indistinguishability and then devise techniques to quantify the probability of reachability between a task and a worker, given their perturbed locations. We investigate both analytical and empirical models for quantifying the worker-task pair reachability and propose task assignment strategies that strike a balance among various metrics such as the number of completed tasks, worker travel distance and system overhead. Extensive experiments on real-world datasets show that our proposed techniques result in minimal disclosure of task locations and no disclosure of worker locations without significantly sacrificing the total number of assigned tasks.
To, Hien, Shahabi, Cyrus, Xiong, Li.  2018.  Privacy-Preserving Online Task Assignment in Spatial Crowdsourcing with Untrusted Server. 2018 IEEE 34th International Conference on Data Engineering (ICDE). :833–844.
With spatial crowdsourcing (SC), requesters outsource their spatiotemporal tasks (tasks associated with location and time) to a set of workers, who will perform the tasks by physically traveling to the tasks' locations. However, current solutions require the locations of the workers and/or the tasks to be disclosed to untrusted parties (SC server) for effective assignments of tasks to workers. In this paper we propose a framework for assigning tasks to workers in an online manner without compromising the location privacy of workers and tasks. We perturb the locations of both tasks and workers based on geo-indistinguishability and then devise techniques to quantify the probability of reachability between a task and a worker, given their perturbed locations. We investigate both analytical and empirical models for quantifying the worker-task pair reachability and propose task assignment strategies that strike a balance among various metrics such as the number of completed tasks, worker travel distance and system overhead. Extensive experiments on real-world datasets show that our proposed techniques result in minimal disclosure of task locations and no disclosure of worker locations without significantly sacrificing the total number of assigned tasks.
2020-03-23
Rustgi, Pulkit, Fung, Carol.  2019.  Demo: DroidNet - An Android Permission Control Recommendation System Based on Crowdsourcing. 2019 IFIP/IEEE Symposium on Integrated Network and Service Management (IM). :737–738.
Mobile and web application security, particularly the areas of data privacy, has raised much concerns from the public in recent years. Most applications, or apps for short, are installed without disclosing full information to users and clearly stating what the application has access to, which often raises concern when users become aware of unnecessary information being collected. Unfortunately, most users have little to no technical expertise in regards to what permissions should be turned on and can only rely on their intuition and past experiences to make relatively uninformed decisions. To solve this problem, we developed DroidNet, which is a crowd-sourced Android recommendation tool and framework. DroidNet alleviates privacy concerns and presents users with high confidence permission control recommendations based on the decision from expert users who are using the same apps. This paper explains the general framework, principles, and model behind DroidNet while also providing an experimental setup design which shows the effectiveness and necessity for such a tool.
2019-02-18
Wang, G., Wang, B., Wang, T., Nika, A., Zheng, H., Zhao, B. Y..  2018.  Ghost Riders: Sybil Attacks on Crowdsourced Mobile Mapping Services. IEEE/ACM Transactions on Networking. 26:1123–1136.
Real-time crowdsourced maps, such as Waze provide timely updates on traffic, congestion, accidents, and points of interest. In this paper, we demonstrate how lack of strong location authentication allows creation of software-based Sybil devices that expose crowdsourced map systems to a variety of security and privacy attacks. Our experiments show that a single Sybil device with limited resources can cause havoc on Waze, reporting false congestion and accidents and automatically rerouting user traffic. More importantly, we describe techniques to generate Sybil devices at scale, creating armies of virtual vehicles capable of remotely tracking precise movements for large user populations while avoiding detection. To defend against Sybil devices, we propose a new approach based on co-location edges, authenticated records that attest to the one-time physical co-location of a pair of devices. Over time, co-location edges combine to form large proximity graphs that attest to physical interactions between devices, allowing scalable detection of virtual vehicles. We demonstrate the efficacy of this approach using large-scale simulations, and how they can be used to dramatically reduce the impact of the attacks. We have informed Waze/Google team of our research findings. Currently, we are in active collaboration with Waze team to improve the security and privacy of their system.
2019-02-08
Chen, Alexander B., Behl, Madhur, Goodall, Jonathan L..  2018.  Trust Me, My Neighbors Say It's Raining Outside: Ensuring Data Trustworthiness for Crowdsourced Weather Stations. Proceedings of the 5th Conference on Systems for Built Environments. :25-28.

Decision making in utilities, municipal, and energy companies depends on accurate and trustworthy weather information and predictions. Recently, crowdsourced personal weather stations (PWS) are being increasingly used to provide a higher spatial and temporal resolution of weather measurements. However, tools and methods to ensure the trustworthiness of the crowdsourced data in real-time are lacking. In this paper, we present a Reputation System for Crowdsourced Rainfall Networks (RSCRN) to assign trust scores to personal weather stations in a region. Using real PWS data from the Weather Underground service in the high flood risk region of Norfolk, Virginia, we evaluate the performance of the proposed RSCRN. The proposed method is able to converge to a confident trust score for a PWS within 10–20 observations after installation. Collectively, the results indicate that the trust score derived from the RSCRN can reflect the collective measure of trustworthiness to the PWS, ensuring both useful and trustworthy data for modeling and decision-making in the future.

2018-05-30
Vlachos, Vasileios, Stamatiou, Yannis C., Madhja, Adelina, Nikoletseas, Sotiris.  2017.  Privacy Flag: A Crowdsourcing Platform for Reporting and Managing Privacy and Security Risks. Proceedings of the 21st Pan-Hellenic Conference on Informatics. :27:1–27:4.

Nowadays we are witnessing an unprecedented evolution in how we gather and process information. Technological advances in mobile devices as well as ubiquitous wireless connectivity have brought about new information processing paradigms and opportunities for virtually all kinds of scientific and business activity. These new paradigms rest on three pillars: i) numerous powerful portable devices operated by human intelligence, ubiquitous in space and available, most of the time, ii) unlimited environment sensing capabilities of the devices, and iii) fast networks connecting the devices to Internet information processing platforms and services. These pillars implement the concepts of crowdsourcing and collective intelligence. These concepts describe online services that are based on the massive participation of users and the capabilities of their devices.in order to produce results and information which are "more than the sum of the part". The EU project Privacy Flag relies exactly on these two concepts in order to mobilize roaming citizens to contribute, through crowdsourcing, information about risky applications and dangerous web sites whose processing may produce emergent threat patterns, not evident in the contributed information alone, reelecting a collective intelligence action. Crowdsourcing and collective intelligence, in this context, has numerous advantages, such as raising privacy-awareness among people. In this paper we summarize our work in this project and describe the capabilities and functionalities of the Privacy Flag Platform.

2017-11-20
Saito, Susumu, Nakano, Teppei, Akabane, Makoto, Kobayashi, Tetsunori.  2016.  Evaluation of Collaborative Video Surveillance Platform: Prototype Development of Abandoned Object Detection. Proceedings of the 10th International Conference on Distributed Smart Camera. :172–177.

This paper evaluates a new video surveillance platform presented in a previous study, through an abandoned object detection task. The proposed platform has a function of automated detection and alerting, which is still a big challenge for a machine algorithm due to its recall-precision tradeoff problem. To achieve both high recall and high precision simultaneously, a hybrid approach using crowdsourcing after image analysis is proposed. This approach, however, is still not clear about what extent it can improve detection accuracy and raise quicker alerts. In this paper, the experiment is conducted for abandoned object detection, as one of the most common surveillance tasks. The results show that detection accuracy was improved from 50% (without crowdsourcing) to stable 95-100% (with crowdsourcing) by majority vote of 7 crowdworkers for each task. In contrast, alert time issue still remains open to further discussion since at least 7+ minutes are required to get the best performance.

2017-10-19
Zhang, Chenwei, Xie, Sihong, Li, Yaliang, Gao, Jing, Fan, Wei, Yu, Philip S..  2016.  Multi-source Hierarchical Prediction Consolidation. Proceedings of the 25th ACM International on Conference on Information and Knowledge Management. :2251–2256.
In big data applications such as healthcare data mining, due to privacy concerns, it is necessary to collect predictions from multiple information sources for the same instance, with raw features being discarded or withheld when aggregating multiple predictions. Besides, crowd-sourced labels need to be aggregated to estimate the ground truth of the data. Due to the imperfection caused by predictive models or human crowdsourcing workers, noisy and conflicting information is ubiquitous and inevitable. Although state-of-the-art aggregation methods have been proposed to handle label spaces with flat structures, as the label space is becoming more and more complicated, aggregation under a label hierarchical structure becomes necessary but has been largely ignored. These label hierarchies can be quite informative as they are usually created by domain experts to make sense of highly complex label correlations such as protein functionality interactions or disease relationships. We propose a novel multi-source hierarchical prediction consolidation method to effectively exploits the complicated hierarchical label structures to resolve the noisy and conflicting information that inherently originates from multiple imperfect sources. We formulate the problem as an optimization problem with a closed-form solution. The consolidation result is inferred in a totally unsupervised, iterative fashion. Experimental results on both synthetic and real-world data sets show the effectiveness of the proposed method over existing alternatives.
2017-09-15
Yang, Bo, He, Suining, Chan, S.-H. Gary.  2016.  Updating Wireless Signal Map with Bayesian Compressive Sensing. Proceedings of the 19th ACM International Conference on Modeling, Analysis and Simulation of Wireless and Mobile Systems. :310–317.

In a wireless system, a signal map shows the signal strength at different locations termed reference points (RPs). As access points (APs) and their transmission power may change over time, keeping an updated signal map is important for applications such as Wi-Fi optimization and indoor localization. Traditionally, the signal map is obtained by a full site survey, which is time-consuming and costly. We address in this paper how to efficiently update a signal map given sparse samples randomly crowdsourced in the space (e.g., by signal monitors, explicit human input, or implicit user participation). We propose Compressive Signal Reconstruction (CSR), a novel learning system employing Bayesian compressive sensing (BCS) for online signal map update. CSR does not rely on any path loss model or line of sight, and is generic enough to serve as a plug-in of any wireless system. Besides signal map update, CSR also computes the estimation error of signals in terms of confidence interval. CSR models the signal correlation with a kernel function. Using it, CSR constructs a sensing matrix based on the newly sampled signals. The sensing matrix is then used to compute the signal change at all the RPs with any BCS algorithm. We have conducted extensive experiments on CSR in our university campus. Our results show that CSR outperforms other state-of-the-art algorithms by a wide margin (reducing signal error by about 30% and sampling points by 20%).

2017-08-22
Lazarova-Molnar, Sanja, Logason, Halldór Þór, Andersen, Peter Grønb\textbackslasha ek, Kj\textbackslasha ergaard, Mikkel Baun.  2016.  Mobile Crowdsourcing of Data for Fault Detection and Diagnosis in Smart Buildings. Proceedings of the International Conference on Research in Adaptive and Convergent Systems. :12–17.

Energy use of buildings represents roughly 40% of the overall energy consumption. Most of the national agendas contain goals related to reducing the energy consumption and carbon footprint. Timely and accurate fault detection and diagnosis (FDD) in building management systems (BMS) have the potential to reduce energy consumption cost by approximately 15-30%. Most of the FDD methods are data-based, meaning that their performance is tightly linked to the quality and availability of relevant data. Based on our experience, faults and relevant events data is very sparse and inadequate, mostly because of the lack of will and incentive for those that would need to keep track of faults. In this paper we introduce the idea of using crowdsourcing to support FDD data collection processes, and illustrate our idea through a mobile application that has been implemented for this purpose. Furthermore, we propose a strategy of how to successfully deploy this building occupants' crowdsourcing application.

2017-05-22
Saab, Farah, Elhajj, Imad, Kayssi, Ayman, Chehab, Ali.  2016.  A Crowdsourcing Game-theoretic Intrusion Detection and Rating System. Proceedings of the 31st Annual ACM Symposium on Applied Computing. :622–625.

One of the main concerns for smartphone users is the quality of apps they download. Before installing any app from the market, users first check its rating and reviews. However, these ratings are not computed by experts and most times are not associated with malicious behavior. In this work, we present an IDS/rating system based on a game theoretic model with crowdsourcing. Our results show that, with minor control over the error in categorizing users and the fraction of experts in the crowd, our system provides proper ratings while flagging all malicious apps.

2017-05-19
Dittus, Martin, Quattrone, Giovanni, Capra, Licia.  2016.  Analysing Volunteer Engagement in Humanitarian Mapping: Building Contributor Communities at Large Scale. Proceedings of the 19th ACM Conference on Computer-Supported Cooperative Work & Social Computing. :108–118.

Organisers of large-scale crowdsourcing initiatives need to consider how to produce outcomes with their projects, but also how to build volunteer capacity. The initial project experience of contributors plays an important role in this, particularly when the contribution process requires some degree of expertise. We propose three analytical dimensions to assess first-time contributor engagement based on readily available public data: cohort analysis, task analysis, and observation of contributor performance. We apply these to a large-scale study of remote mapping activities coordinated by the Humanitarian OpenStreetMap Team, a global volunteer effort with thousands of contributors. Our study shows that different coordination practices can have a marked impact on contributor retention, and that complex task designs can be a deterrent for certain contributor groups. We close by providing recommendations about how to build and sustain volunteer capacity in these and comparable crowdsourcing systems.

2017-05-17
Wang, Bolun.  2016.  Defending Against Sybil Devices in Crowdsourced Mapping Services. Proceedings of on MobiSys 2016 PhD Forum. :3–4.

Crowdsourcing is an unique and practical approach to obtain personalized data and content. Its impact is especially significant in providing commentary, reviews and metadata, on a variety of location based services. In this study, we examine reliability of the Waze mapping service, and its vulnerability to a variety of location-based attacks. Our goals are to understand the severity of the problem, shed light on the general problem of location and device authentication, and explore the efficacy of potential defenses. Our preliminary results already show that a single attacker with limited resources can cause havoc on Waze, producing ``virtual'' congestion and accidents, automatically re-routing user traffic, and compromising user privacy by tracking users' precise movements via software while staying undetected. To defend against these attacks, we propose a proximity-based Sybil detection method to filter out malicious devices.

2017-03-07
Rifat, Md. Rashidujjaman, Siddique, Aysha, Abouzied, Azza, Chen, Jay.  2016.  From Alley to Landfill: Challenges of and Design Opportunities for Cleaning Dhaka's Communal Trash. Proceedings of the Eighth International Conference on Information and Communication Technologies and Development. :9:1–9:10.

Garbage is an endemic problem in developing cities due to the continual influx of migrants from rural areas coupled with deficient municipal capacity planning. In cities like Dhaka, open waste dumps contribute to the prevalence of disease, environmental contamination, catastrophic flooding, and deadly fires. Recent interest in the garbage problem has prompted cursory proposals to introduce technology solutions for mapping and fundraising. Yet, the role of technology and its potential benefits are unexplored in this large-scale problem. In this paper, we contribute to the understanding of the waste ecology in Dhaka and how the various actors acquire, perform, negotiate, and coordinate their roles. Within this context, we explore design opportunities for using computing technologies to support collaboration between waste pickers and residents of these communities. We find opportunities in the presence of technology and the absence of mechanisms to facilitate coordination of community funding and crowd work.

2015-05-04
Alsaleh, M.N., Al-Shaer, E.A..  2014.  Security configuration analytics using video games. Communications and Network Security (CNS), 2014 IEEE Conference on. :256-264.

Computing systems today have a large number of security configuration settings that enforce security properties. However, vulnerabilities and incorrect configuration increase the potential for attacks. Provable verification and simulation tools have been introduced to eliminate configuration conflicts and weaknesses, which can increase system robustness against attacks. Most of these tools require special knowledge in formal methods and precise specification for requirements in special languages, in addition to their excessive need for computing resources. Video games have been utilized by researchers to make educational software more attractive and engaging. Publishing these games for crowdsourcing can also stimulate competition between players and increase the game educational value. In this paper we introduce a game interface, called NetMaze, that represents the network configuration verification problem as a video game and allows for attack analysis. We aim to make the security analysis and hardening usable and accurately achievable, using the power of video games and the wisdom of crowdsourcing. Players can easily discover weaknesses in network configuration and investigate new attack scenarios. In addition, the gameplay scenarios can also be used to analyze and learn attack attribution considering human factors. In this paper, we present a provable mapping from the network configuration to 3D game objects.