Mobile sensing has become a promising paradigm for mobile users to obtain information by task crowd- sourcing. However, due to the social preferences of mobile users, the quality of sensing reports may be impacted by the underlying social attributes and selfishness of individuals. Therefore, it is crucial to con- sider the social impacts and trustworthiness of mobile users when selecting task participants in mobile sensing. In this paper, we propose a Social Aware Crowdsourcing with Reputation Management (SACRM) scheme to select the well-suited participants and allocate the task rewards in mobile sensing. Specifically, we consider the social attributes, task delay and reputation in crowdsourcing and propose a participant selection scheme to choose the well-suited participants for the sensing task under a fixed task budget. A report assessment and rewarding scheme is also introduced to measure the quality of the sensing reports and allocate the task rewards based the assessed report quality. In addition, we develop a reputation management scheme to evaluate the trustworthiness and cost performance ratio of mobile users for par- ticipant selection. Theoretical analysis and extensive simulations demonstrate that SACRM can efficiently improve the crowdsourcing utility and effectively stimulate the participants to improve the quality of their sensing reports.
The majority of the existing incentive mechanisms are beneficial to stimulate the user participation, however, data assessment and reputation management are desired and critical to evaluate the trustworthiness of sensing data and mobile users @cite_13 @cite_16 @cite_8 @cite_7 @cite_14 @cite_23 . Zhang et. al. @cite_13 propose a robust trajectory estimation strategy, called TrMCD, to alleviate the negative influence of abnormal crowdsourced user trajectories and identify the normal and abnormal users, as well as to mitigate the impact of the spatial unbalanced crowdsourced trajectories. Huang et. al. @cite_23 employ the Gompertz function @cite_29 to compute the device reputation score and evaluate the trustworthiness of the contributed data. Since the reputation scores associated with the specific contributions can be used to identify the participants, privacy issues are highlighted in the reputation system design of mobile sensing @cite_15 @cite_16 @cite_14 . Wang et. al. @cite_15 propose a privacy-preserving reputation framework to evaluate the trustiness of the sensing reports and the participants based on the blind signatures. Christin et. al. @cite_16 propose an anonymous reputation framework, called as IncogniSense, which generates periodic pseudonyms by blind signature and transfers reputation between these pseudonyms.
@cite_14 @cite_7 @cite_8 @cite_29 @cite_23 @cite_15 @cite_16 @cite_13
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The continual advancement in semiconductor technology has enabled vendors to integrate an increasing number of sensors, e.g., accelerometer, gyroscope, digital compass, high resolution cameras and others, in modern mobile phones. Combining with the ever expanding market penetration of mobile phones, the onboard sensors are driving the sensing community towards a new paradigm called participatory sensing in which ordinary citizens voluntarily collect and share information from their local environment using personal mobile devices. The inherent openness of this platform is a double-edged sword. While encouraging user participation on the one hand, it also makes it easy to contribute corrupted data. As such, data trustworthiness becomes a key issue which needs to be addressed to ensure sustainable development of this emerging paradigm. In this paper, we propose a reputation system in which a reputation score is calculated for each device as a reflection of the trustworthiness of its sensor data. We adopt the Gompertz function as a fundamental building block of our system, since it is better suited to deal with the unique characteristics of participatory sensing. We present an application-agnostic implementation of the system, which can work with a wide variety of participatory sensing applications. We evaluate the performance of our reputation system in the context of two real-world participatory sensing applications. Our results show that the proposed reputation system outperforms existing solutions by up to a factor of six. Reputation systems rate the contributions to participatory sensing campaigns from each user by associating a reputation score. The reputation scores are used to weed out incorrect sensor readings. However, an adversary can deanonmyize the users even when they use pseudonyms by linking the reputation scores associated with multiple contributions. Since the contributed readings are usually annotated with spatiotemporal information, this poses a serious breach of privacy for the users. In this paper, we address this privacy threat by proposing a framework called IncogniSense. Our system utilizes periodic pseudonyms generated using blind signature and relies on reputation transfer between these pseudonyms. The reputation transfer process has an inherent trade-off between anonymity protection and loss in reputation. We investigate by means of extensive simulations several reputation cloaking schemes that address this tradeoff in different ways. Our system is robust against reputation corruption and a prototype implementation demonstrates that the associated overheads are minimal. Participatory sensing is a revolutionary new paradigm in which volunteers collect and share information from their local environment using mobile phones. The inherent openness of this platform makes it easy to contribute corrupted data. This paper proposes a novel reputation system that employs the Gompertz function for computing device reputation score as a reflection of the trustworthiness of the contributed data. We implement this system in the context of a participatory noise monitoring application and conduct extensive real-world experiments using Apple iPhones. Experimental results demonstrate that our scheme achieves three-fold improvement in comparison with the state-of-the-art Beta reputation scheme. The ubiquity of mobile devices has brought forth the concept of participatory sensing, whereby ordinary citizens can now contribute and share information from the urban environment. However, such applications introduce a key research challenge: preserving the privacy of the individuals contributing data. In this paper, we study two different privacy concepts, k-anonymity and l-diversity, and demonstrate how their privacy models can be applied to protect users' spatial and temporal privacy in the context of participatory sensing. The first part of the paper focuses on schemes implementing k-anonymity. We propose the use of microaggregation, a technique used for facilitating disclosure control in databases, as an alternate to tessellation, which is the current state-of-the-art for location privacy in participatory sensing applications. We conduct a comparative study of the two techniques and demonstrate that each has its advantage in certain mutually exclusive situations. We then propose the Hybrid Variable size Maximum Distance to Average Vector (Hybrid-VMDAV) algorithm, which combines the positive aspects of microaggregation and tessellation. The second part of the paper addresses the limitations of the k-anonymity privacy model. We employ the principle of l-diversity and propose an l-diverse version of VMDAV (LD-VMDAV) as an improvement. In particular, LD-VMDAV is robust in situations where an adversary may have gained partial knowledge about certain attributes of the victim. We evaluate the performances of our proposed techniques using real-world traces. Our results show that Hybrid-VMDAV improves the percentage of positive identifications made by an application server by up to 100 and decreases the amount of information loss by about 40 . We empirically show that LD-VMDAV always outperforms its k-anonymity counterpart. In particular, it improves the ability of the applications to accurately interpret the anonymized location and time included in user reports. Our studies also confirm that perturbing the true locations of the users with random Gaussian noise can provide an extra layer of protection, while causing little impact on the application performance.