Context aware systems are able to adapt their behavior according to the environment in which the user is. They can be integrated into an Internet of Things (IoT) infrastructure, allowing a better perception of the user’s physical environment by collecting context data from sensors embedded in devices known as smart objects. An IoT extension called the Internet of Mobile Things (IoMT) suggests new scenarios in which smart objects and IoT gateways can move autonomously or be moved easily. In a comprehensive view, Quality of Context (QoC) is a term that can express quality requirements of context aware applications. These requirements can be those related to the quality of information provided by the sensors (e.g., accuracy, resolution, age, validity time) or those referring to the quality of the data distribution service (e.g, reliability, delay, delivery time). Some functionalities of context aware applications and/or decision-making processes of these applications and their users depend on the level of quality of context available, which tend to vary over time for various reasons. Reviewing the literature, it is possible to verify that the quality of context support provided by IoT-oriented middleware systems still has limitations in relation to at least four relevant aspects: (i) quality of context provisioning; (ii) quality of context monitoring; (iii) support for heterogeneous device and technology management; (iv) support for reliable data delivery in mobility scenarios. This paper presents two main contributions: (i) a state-of-the-art survey specifically aimed at analyzing the middleware with quality of context support and; (ii) a new middleware with comprehensive quality of context support for Internet of Things Applications. The proposed middleware was evaluated and the results are presented and discussed in this article, which also shows a case study involving the development of a mobile remote patient monitoring application that was developed using the proposed middleware. This case study highlights how middleware components were used to meet the quality of context requirements of the application. In addition, the proposed middleware was compared to other solutions in the literature.
Due to emerging new technologies in the development of interactive 3D applications (eg games and virtual reality), stereoscopic visualization is becoming a common feature. However, this fact does not solve some problems (nausea and headaches -cybersickness) related with the generation of this type of visualization. Some parameters have to be carefully chosen to create a comfortable stereo view, for example, eye distance, zero parallax plane distance, and the treatment of partially clipped objects in negative parallax. This paper presents a technique based on a CubeMap structure to dynamically adjust stereo parameters during the usage of two virtual reality tools in multi-scale 3D scenarios.
Three-dimensional computer-aided design (3D CAD) modeling and reviewing is one of the most common engineering project tools. Interaction in these environments is characterized by the need for a high precision level to execute specific tasks. Generally this kind of task uses specific interaction devices with 4 or more degrees of freedom, such as 3D mice. Currently applications involving 3D interaction use interaction devices for object modeling or for the implementation of navigation, selection and manipulation techniques in a virtual environment. A related problem is the need to control naturally non-immersive tasks, such as symbolic input (e.g., text, photos). In addition, the steep learning curve to handle such nonconventional devices is a recurring problem. The addition of sensors and the popularization of smart-phones and tablets, allowed the use of such devices in virtual engineering environments. These devices, differs to other devices by the possibility of including additional information and performing naturally non-immersive tasks.This work presents a 3D interaction tablet-based tool, which allows the aggregation of all major 3D interaction topics, such as navigation, selection, manipulation, system control and symbolic input. To validate the proposed tool,the SimUEP-Ambsim application was chosen, an oil and gas simulator that has the complexity needed and which allows the use of all techniques implemented. Then, the tool was tested in another application, a photo-voltaic solar plant simulator, in order to evaluate the generality of this work concept.
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