No abstract

Improving the sustainability in agriculture is nowadays an important challenge. The automation of irrigation processes via low-cost sensors can to spread technological advances in a sector very influenced by economical costs. This article presents an auto-calibrated pH sensor able to detect and adjust the imbalances in the pH levels of the nutrient solution used in hydroponic agriculture. The sensor is composed by a pH probe and a set of micropumps that sequentially pour the different liquid solutions to maintain the sensor calibration and the water samples from the channels that contain the nutrient solution. To implement our architecture, we use an auto-calibrated pH sensor connected to a wireless node. Several nodes compose our wireless sensor networks (WSN) to control our greenhouse. The sensors periodically measure the pH level of each hydroponic support and send the information to a data base (DB) which stores and analyzes the data to warn farmers about the measures. The data can then be accessed through a user-friendly, web-based interface that can be accessed through the Internet by using desktop or mobile devices. This paper also shows the design and test bench for both the auto-calibrated pH sensor and the wireless network to check their correct operation.

Security in networks of unmanned aerial vehicles for surveillance with an agent-based approach inspired by the principles of blockchain. Ad Hoc Networks, 86, pp. 72-82.

Networks' creation is getting more and more required, anytime, anywhere. Devices that can participate on these networks can be quite different among them. Sensors, mobiles, home appliances, or other type of devices will have to collaborate to increase and improve the services provided to clients. In the same way, network configuration, security mechanisms establishment, and optimal performance control must be done by them. Some of these devices could have limited resources to work, sometimes even resources restriction not existing, they must work to optimize network traffic. In this article, we center our researching on spontaneous networks. We propose a secure spontaneous ad-hoc network, based on direct peer-to-peer interaction and communities' creation to grant a quick, easy, and secure access to users to surf the Web. Each device will have an identity in the network. Each community will also have an identity and will act as a unity on a world based on Internet connection. Security will be established in the moment they access to the network through the use of the trust chain generated by nodes. Trust is modified by each node on the basis of nodes behavior.

Agent-based simulators (ABSs) have successfully allowed practitioners to estimate the outcomes of certain input circumstances in several domains. Although some techniques and processes provide hints about the construction of these systems, there are still some aspects that are not discussed in the literature. In this context, the current approach presents a technique for developing ABSs. This technique especially discusses the simulation of the decision-making processes of agents and the different ways of evolving their attributes in nondeterministic scenarios. The current approach includes a framework for developing ABSs as mobile apps and online tools. This work illustrates the current approach with a case study in the field of health and welfare. This case study has also been implemented with the most similar technique from the literature for comparing both techniques. The presented technique improved the simulated outcomes in terms of similarity with the real ones, as proved with several statistical tests. The obtained ABS is more efficient and reliable for large amounts of agents (e.g. 10,000-400,000 agents). The development time was also lower. Both the framework and the implementation of the case study are freely distributed as open-source to ensure the reproducibility of the experiments and to assist practitioners in applying the current approach.

No abstract

Cloud computing helps users and companies to share computing resources instead of having local servers or personal devices to handle the applications. Smart devices are becoming one of the main information processing devices. Their computing features are reaching levels that let them create a mobile cloud computing network. But sometimes they are not able to create it and collaborate actively in the cloud because it is difficult for them to build easily a spontaneous network and configure its parameters. For this reason, in this paper, we are going to present the design and deployment of a spontaneous ad hoc mobile cloud computing network. In order to perform it, we have developed a trusted algorithm that is able to manage the activity of the nodes when they join and leave the network. The paper shows the network procedures and classes that have been designed. Our simulation results using Castalia show that our proposal presents a good efficiency and network performance even by using high number of nodes.

Sensor systems for the Internet of Things (IoT) make it possible to continuously monitor people, gathering information without any extra effort from them. Thus, the IoT can be very helpful in the context of early disease detection, which can improve peoples’ quality of life by applying the right treatment and measures at an early stage. This paper presents a new use of IoT sensor systems—we present a novel three-door smart cupboard that can measure the memory of a user, aiming at detecting potential memory losses. The smart cupboard has three sensors connected to a Raspberry Pi, whose aim is to detect which doors are opened. Inside of the Raspberry Pi, a Python script detects the openings of the doors, and classifies the events between attempts of finding something without success and the events of actually finding it, in order to measure the user’s memory concerning the objects’ locations (among the three compartments of the smart cupboard). The smart cupboard was assessed with 23 different users in a controlled environment. This smart cupboard was powered by an external battery. The memory assessments of the smart cupboard were compared with a validated test of memory assessment about face–name associations and a self-reported test about self-perceived memory. We found a significant correlation between the smart cupboard results and both memory measurement methods. Thus, we conclude that the proposed novel smart cupboard successfully measured memory.