Browsing by Author "Al-Hamadi, Hamid"
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- COSTA: Composite Trust-Based Asset-Task Assignment in Mobile Ad Hoc NetworksCho, Jin-Hee; Al-Hamadi, Hamid; Chen, Ing-Ray (IEEE, 2019)In mobile ad hoc networks (MANETs), asset-task assignment problems have been explored with vastly different approaches. Considering the unique characteristics of MANET environments, such as no centralized trusted entity, a lack of resources, and high-security vulnerabilities, resource allocation is not a trivial problem particularly for situations where a mobile team aims to successfully complete a common mission. The existing approaches have studied asset-task assignment problems by best matching a node's functionality and requirements of a given task. In this paper, we propose a task assignment protocol using the concept of multidimensional trust, namely, CompoSite Trust-based Assignment (COSTA), aiming to maximize the completion ratio of a common mission consisting of multiple tasks by balancing trust and risk in executing them. Based on the core concept of trust defined as the willingness to take the risk in performing a given task, COSTA selects qualified nodes for a given task while meeting an acceptable risk level for executing multiple tasks contributing to successful mission completion. Given a mission consisting of dynamic multiple tasks, we model each task with importance, urgency, and difficulty characteristics and use them for selecting qualified members. In addition, we model a node's risk behavior (i.e., risk-seeking, risk-neutral, and risk-averse) and investigate its impact on mission performance where a payoff is given for member selection and task execution. We formulate an optimization problem for the task assignment using integer linear programming (ILP). Our simulation results validated with ILP solutions demonstrate the existence of an optimal acceptable risk level that best balances trust and risk so as to maximize the mission completion ratio. We conduct a comprehensive comparative analysis and show that COSTA achieves a higher mission completion ratio while incurring a lower communication overhead compared with non-trust-based counterparts.
- Trust Management of Smart Service CommunitiesAl-Hamadi, Hamid; Chen, Ing-Ray; Cho, Jin-Hee (IEEE, 2019)In this paper, the notion of a smart service community is proposed to address the grand challenge of a huge number of the Internet-of-Things (IoT) devices providing similar services in a smart city environment (e.g., parking, food, healthcare, transportation, and entertainment). We propose that a smart service community be built as a cloud utility accessible via a mobile application installed in user-owned IoT devices, such as smartphones. The cloud utility provides cloud-based interfaces, including registration, service satisfaction reporting, recommender credibility reporting, and service recommendation, with the goal of recommending the best service providers based on a user's specified service performance criteria. The trust-based service management techniques, utilizing the IoT-assisted technology, are developed to automatically measure service ratings and recommender credibility ratings, and compute one-to-one subjective trust scores to allow a user to select the best service providers among all. The feasibility of the proposed approach is demonstrated over contemporary service ranking systems using a smart food service community for which the major performance metric is the service wait time.