5,732 research outputs found
Communication and Control in Collaborative UAVs: Recent Advances and Future Trends
The recent progress in unmanned aerial vehicles (UAV) technology has
significantly advanced UAV-based applications for military, civil, and
commercial domains. Nevertheless, the challenges of establishing high-speed
communication links, flexible control strategies, and developing efficient
collaborative decision-making algorithms for a swarm of UAVs limit their
autonomy, robustness, and reliability. Thus, a growing focus has been witnessed
on collaborative communication to allow a swarm of UAVs to coordinate and
communicate autonomously for the cooperative completion of tasks in a short
time with improved efficiency and reliability. This work presents a
comprehensive review of collaborative communication in a multi-UAV system. We
thoroughly discuss the characteristics of intelligent UAVs and their
communication and control requirements for autonomous collaboration and
coordination. Moreover, we review various UAV collaboration tasks, summarize
the applications of UAV swarm networks for dense urban environments and present
the use case scenarios to highlight the current developments of UAV-based
applications in various domains. Finally, we identify several exciting future
research direction that needs attention for advancing the research in
collaborative UAVs
GNSS-free outdoor localization techniques for resource-constrained IoT architectures : a literature review
Large-scale deployments of the Internet of Things (IoT) are adopted for performance
improvement and cost reduction in several application domains. The four main IoT application
domains covered throughout this article are smart cities, smart transportation, smart healthcare, and
smart manufacturing. To increase IoT applicability, data generated by the IoT devices need to be
time-stamped and spatially contextualized. LPWANs have become an attractive solution for outdoor
localization and received significant attention from the research community due to low-power,
low-cost, and long-range communication. In addition, its signals can be used for communication
and localization simultaneously. There are different proposed localization methods to obtain the
IoT relative location. Each category of these proposed methods has pros and cons that make them
useful for specific IoT systems. Nevertheless, there are some limitations in proposed localization
methods that need to be eliminated to meet the IoT ecosystem needs completely. This has motivated
this work and provided the following contributions: (1) definition of the main requirements and
limitations of outdoor localization techniques for the IoT ecosystem, (2) description of the most
relevant GNSS-free outdoor localization methods with a focus on LPWAN technologies, (3) survey
the most relevant methods used within the IoT ecosystem for improving GNSS-free localization
accuracy, and (4) discussion covering the open challenges and future directions within the field.
Some of the important open issues that have different requirements in different IoT systems include
energy consumption, security and privacy, accuracy, and scalability. This paper provides an overview
of research works that have been published between 2018 to July 2021 and made available through
the Google Scholar database.5311-8814-F0ED | Sara Maria da Cruz Maia de Oliveira PaivaN/
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Interface design for a remote guidance system for the blind: Using dual-screen displays
This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.The mobility for the visually impaired people is one of the main challenges that researchers are still facing around the world. Although some projects have been conducted to improve the mobility of visually impaired people, further research is still needed. One of these projects is Brunel Remote Guidance System (BRGS). BRGS is aimed to assist visually impaired users in avoiding obstacles and reaching their destinations safely by providing online instructions via a remote sighted guide.
This study comes as continuation of the development process of BRGS; the main aim that has been achieved of this research is the optimisation of the interface design for the system guide terminal. This helps the sighted guide to assist the VIUs to avoid obstacles safely and comfortably in the micro-navigation, as well as to keep them on the right track to reach their destination in the macro-navigation. After using the content analysis, the performance factors and their assessments method were identified in each BRGS‘ element, which concluded that there is a lack of research on the guide terminal setup and the assessment method for the sighted guide performance. Furthermore, there are no model to assist the sighted guide performance and two-screen displays used in the literature review and similar projects. A model was designed as a platform to conduct the evaluation on sighted guide performance. Based on this model, the computer-based simulation was established and tested, which made the simulation is ready for next task; the evaluation of the sighted guide performance. The conducted study determined the effects of the two-screen displays on the recognition performance of the 80 participants in the guide terminal. The performance was measured with the context of four different resolution conditions. The study was based on a simulation technique, which is consisted of two key performance elements in order to examine the sighted guide performance; the macro-navigation element and the micro-navigation element. The results show that the two-screen displays have an effect on the performance of the sighted guide. The optimum setup for the two-screen displays for the guide terminal consisted of a big digital map screen display (4CIF [704p x 576p]) and a small video image screen display (CIF [352p x 288p]), which one of the four different resolutions. This interface design has been recommended as a final setup in the guide terminal
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Context-awareness for mobile sensing: a survey and future directions
The evolution of smartphones together with increasing computational power have empowered developers to create innovative context-aware applications for recognizing user related social and cognitive activities in any situation and at any location. The existence and awareness of the context provides the capability of being conscious of physical environments or situations around mobile device users. This allows network services to respond proactively and intelligently based on such awareness. The key idea behind context-aware applications is to encourage users to collect, analyze and share local sensory knowledge in the purpose for a large scale community use by creating a smart network. The desired network is capable of making autonomous logical decisions to actuate environmental objects, and also assist individuals. However, many open challenges remain, which are mostly arisen due to the middleware services provided in mobile devices have limited resources in terms of power, memory and bandwidth. Thus, it becomes critically important to study how the drawbacks can be elaborated and resolved, and at the same time better understand the opportunities for the research community to contribute to the context-awareness. To this end, this paper surveys the literature over the period of 1991-2014 from the emerging concepts to applications of context-awareness in mobile platforms by providing up-to-date research and future research directions. Moreover, it points out the challenges faced in this regard and enlighten them by proposing possible solutions
Reliable and efficient data dissemination schemein VANET: a review
Vehicular ad-hoc network (VANET), identified as a mobile ad hoc network MANETs with several added constraints. Basically, in VANETs, the network is established on the fly based on the availability of vehicles on roads and supporting infrastructures along the roads, such as base stations. Vehicles and road-side infrastructures are required to provide communication facilities, particularly when enough vehicles are not available on the roads for effective communication. VANETs are crucial for providing a wide range of safety and non-safety applications to road users. However, the specific fundamental problem in VANET is the challenge of creating effective communication between two fast-moving vehicles. Therefore, message routing is an issue for many safety and non-safety of VANETs applications. The challenge in designing a robust but reliable message dissemination technique is primarily due to the stringent QoS requirements of the VANETs safety applications. This paper investigated various methods and conducted literature on an idea to develop a model for efficient and reliable message dissemination routing techniques in VANET
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