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When urban agriculture is addressed at a family scale, known as urban gardening, it is assumed as a non-commercial activity where some family members voluntarily take care of the plantation during their free time. If technology is going to be used to support such a process, then the solutions should consider the particularities of these gardeners (e.g., life dynamics and culture) to make them adoptable. The literature reports several urban agriculture experiences in Western countries and Southeast Asia; however, this activity has been poorly explored in South American countries, particularly at a family scale and considering the culture and the affordability of the solutions. This article presents an experience report of urban gardening in Peru, where a prototype of an IoT system and a mobile application were conceived, implemented, and used to support the gardening of vegetables at a family scale, considering the cultural aspects of the gardeners. This experience obtained positive results in terms of tomato production, mainly showing the system’s capability to self-adapt its behavior to consider the cultivation conditions of these urban gardeners. To the best of our knowledge, this is the first IoT system that can be iteratively adjust its behavior to improve the chances of being adopted by a particular end-user population (i.e., gardeners).

LoRaWAN is a long range and low power protocol devised for connecting devices under the Internet of Things (IoT) paradigm. This protocol was not conceived to support real-time message delivery; therefore, it is not always feasible using it to support IoT solutions involving large wireless sensors networks and time constraint messaging, e.g., in early warning systems for natural hazards, remote monitoring of industrial machinery or autonomous control of transportation systems. This paper presents a model that provides certainty, at the design time of IoT systems, about the real-time communication capability of their supporting network. It allows solution designers: (1) to decide if developing or not a real-time IoT solution based on the feasibility of its communication infrastructure, and (2) to improve the communication infrastructure to try making real-time communication feasible using LoRaWAN.

LoRaWAN has become the most widely used low-power wide-area network technology to implement monitoring solutions based on the Internet of remote things (IoRT) paradigm. Typically, these solutions interconnect remote sensing areas and data processing infrastructure located in urban centers. The operation expenses of these solutions depend mainly on the traffic sent through the network backhaul, i.e., the link that connects the remote sensing area and the urban area where the data are usually processed and stored. This service is provided by telecommunication companies and represents the main operation cost of IoRT solutions. These expenses usually limit the affordability of IoRT-based systems in developing countries, and also in scenarios where the operational cost is an issue to address. This paper presents an extension to the LoRaWAN protocol, named Node-Aware-LoRaWAN (NA-LoRaWAN), that reduces the traffic in the backhaul, thus decreasing the operational expenses of IoRT-based systems. In order to evaluate the performance of NA-LoRaWAN, it was compared to a regular LoRaWAN implementation. Depending on the network scenario, the proposed extension reduced the traffic through the backhaul in the range of 12–34%. This extension opens several opportunities to use IoRT solutions in application domains with a low operational budget, e.g., precision agriculture, environmental monitoring and natural hazards’ early detection.

IoT systems monitoring or controlling the behavior of smart environments frequently require to count on real-time message delivery, in order to support decision making and eventually coordinate the individual behavior of their system components. Several initiatives propose the use of opportunistic networks to address this requirement, but none of them support message delivery considering time constraints. Therefore, the support that they provide is partially suitable for conducting real-time monitoring and control of smart environments. In order to address that challenge, this paper proposes a message propagation model for opportunistic networks that considers the participation of heterogeneous devices, and guarantees the real-time behavior of the network by bounding the maximum delay for messages transmission. The message propagation is modeled using an analytical approach that reduces the effort of prototyping and analyzing the properties of these networks. Two running examples, based on disaster relief efforts, are used to illustrate the feasibility of implementing the proposed message dissemination model on opportunistic networks and, thus, to allow real-time communication in the field. These results showed that is feasible not only the implementation of these networks but also their representation using an analytical approach. The networks for both example scenarios were then simulated to confirm the results obtained using the analytical approach. Given the positive results, the proposed model and its representation open several opportunities to model smart environments and design IoT systems that require real-time communication in opportunistic networks.

The need to use mobile technology in urban emergency response processes has recently been identified, given the importance of having relevant information to make decisions in these scenarios. The data visualization on small mobile devices, such as PDAs or smartphones, is a critical aspect to make appropriate and on-time decisions. This criticality particularly occurs due to the small size of their screens to show geographical data. This article presents a strategy to select and display the most relevant “Points of Interest” on a digital map, according to the emergency influence area. This strategy was implemented on the MobileMap tool, and then it was evaluated through simulated emergency situations. Commanders of various Chilean Fire Companies participated in this evaluation.

The effectiveness of the work performed during disaster relief efforts is highly dependent on the coordination of activities conducted by the first responders deployed in the affected area. Such coordination, in turn, depends on an appropriate management of geo-referenced information. Therefore, enabling first responders to count on positioning capabilities during these activities is vital to increase the effectiveness of the response process. The positioning methods used in this scenario must assume a lack of infrastructure-based communication and electrical energy, which usually characterizes affected areas. Although positioning systems such as the Global Positioning System (GPS) have been shown to be useful, we cannot assume that all devices deployed in the area (or most of them) will have positioning capabilities by themselves. Typically, many first responders carry devices that are not capable of performing positioning on their own, but that require such a service. In order to help increase the positioning capability of first responders in disaster-affected areas, this paper presents a context-aware positioning model that allows mobile devices to estimate their position based on information gathered from their surroundings. The performance of the proposed model was evaluated using simulations, and the obtained results show that mobile devices without positioning capabilities were able to use the model to estimate their position. Moreover, the accuracy of the positioning model has been shown to be suitable for conducting most first response activities.

The Internet of Things (IoT) has inspired solutions that are already available for addressing problems in various application scenarios, such as healthcare, security, emergency support and tourism. However, there is no clear approach to modeling these systems and envisioning their capabilities at the design time. Therefore, the process of designing these systems is ad hoc and its real impact is evaluated once the solution is already implemented, which is risky and expensive. This paper proposes a modeling approach that uses human-centric wireless sensor networks to specify and evaluate models of IoT-based systems at the time of design, avoiding the need to spend time and effort on early implementations of immature designs. It allows designers to focus on the system design, leaving the implementation decisions for a next phase. The article illustrates the usefulness of this proposal through a running example, showing the design of an IoT-based solution to support the first responses during medium-sized or large urban incidents. The case study used in the proposal evaluation is based on a real train crash. The proposed modeling approach can be used to design IoT-based systems for other application scenarios, e.g., to support security operatives or monitor chronic patients in their homes.

The interaction among components of an IoT-based system usually requires using low latency or real time for message delivery, depending on the application needs and the quality of the communication links among the components. Moreover, in some cases, this interaction should consider the use of communication links with poor or uncertain Quality of Service (QoS). Research efforts in communication support for IoT scenarios have overlooked the challenge of providing real-time interaction support in unstable links, making these systems use dedicated networks that are expensive and usually limited in terms of physical coverage and robustness. This paper presents an alternative to address such a communication challenge, through the use of a model that allows soft real-time interaction among components of an IoT-based system. The behavior of the proposed model was validated using state machine theory, opening an opportunity to explore a whole new branch of smart distributed solutions and to extend the state-of-the-art and the-state-of-the-practice in this particular IoT study scenario.

The response conducted by emergency units after natural disasters, such as earthquakes, has to be coordinated, fast, and efficient in order to rescue and care for the victims, keeping all the population—and the units themselves—safe amidst the usual chaos. Outages in wireless networks, as well as fiber- or copper-based landline and Internet connections, are to be expected in these situations, so alternative communication solutions must be considered. To contribute in this duty, we propose a communication system that uses the LoRaWAN architecture to allow citizens to report their status to emergency units and public authorities with simple messages and interaction mechanisms. The purpose of this system is to keep people and first responders connected, and thus improve the capability to coordinate the evacuation activities. To analyze the system performance and capabilities, we model a district of Coquimbo, a harbor town in Chile that houses approximately 28,000 people in 7500 homes, and simulate it with a baseline configuration. We explore several settings for the system in order to determine its characteristics and limitations, to better understand its scalability and portability to other environments, and to outline the remaining challenges to make the system attain specific performance guarantees.

The response to natural disasters usually requires evacuation procedures that should be followed in a quick and orderly fashion. While census data provide information on the population distribution during sleeping hours, the evacuation procedure may arrive at any moment of the day, even when people are not at home; e.g., in their daily activities. This particular situation causes preparedness plans based on census information to become minimally effective; therefore, more dynamic and context-aware strategies are required to properly address these evacuation processes. In this paper, an evacuation supporting system, based on IoT-networked devices, is proposed to guide people to safe places or shelters once the alert of an extreme event has been issued. The system is interactive and support crowd-sensing; this allows people to upload information on the state of the routes and the shelters, thus keep an updated status of the evacuation routes. The contribution of the paper is twofold. On one side, an evolutionary algorithm is proposed to provide coverage in a breadcrumb deployment of information posts called witness units. On the other, an application based on geographical information system is presented as an intermediary between the witness units and the users; this application guides people towards safe places or shelters.

The adoption of mobile and ubiquitous solutions that involve participatory or opportunistic sensing increases every day. This situation has highlighted the relevance of optimizing the energy consumption of these solutions, because their operation depends on the devices’ battery lifetimes. This article presents a study that intends to understand how the prediction of topology control messages in human-centric wireless sensor networks can be used to help reduce the energy consumption of the participating devices. In order to do that, five research questions have been defined and a study based on simulations was conducted to answer these questions. The obtained results help identify suitable mobile computing scenarios where the prediction of topology control messages can be used to save energy of the network nodes. These results also allow estimating the percentage of energy saving that can be expected, according to the features of the work scenario and the participants behavior. Designers of mobile collaborative applications that involve participatory or opportunistic sensing, can take advantage of these findings to increase the autonomy of their solutions.

Navigation in indoor environments is highly challenging for the severely visually impaired, particularly in spaces visited for the first time. Several solutions have been proposed to deal with this challenge. Although some of them have shown to be useful in real scenarios, they involve an important deployment effort or use artifacts that are not natural for blind users. This paper presents an indoor navigation system that was designed taking into consideration usability as the quality requirement to be maximized. This solution enables one to identify the position of a person and calculates the velocity and direction of his movements. Using this information, the system determines the user’s trajectory, locates possible obstacles in that route, and offers navigation information to the user. The solution has been evaluated using two experimental scenarios. Although the results are still not enough to provide strong conclusions, they indicate that the system is suitable to guide visually impaired people through an unknown built environment.

The diversification and evolution of social media tools conveys users to adopt new systems and use new features of existing ones. Although this dynamism is suitably addressed by digital natives, it usually limits the technology adoption capability of digital immigrants, e.g., older adults, who react more slowly and with less confidence to the introduction of new computing systems. In order to support digital immigrants to deal with such a challenge, this paper proposes a ubiquitous system that mediates the communication supported by client applications and regular social interaction media such as, Gmail, WhatsApp, and Telegram. The system, named Social Message Translator, translates social media messages in both directions and self-adapts the process according to the behavior of end-users. Thus, it deals with the digital diversification of the former and also with the changes in the social media preferences of end-users. Consequently, digital immigrants are able to perceive as useful the supporting technology for longer time spans. The correctness of the message translation system was evaluated using a laboratory case study. The obtained results were highly positive, opening several opportunities to use this translator in several social interaction scenarios.

Software applications have been identified as potentially suitable tools to assist older adults in several aspects of their lives, like healthcare, emotional support and personal security. However, developing usable and useful applications for this population represents an important challenge, given that no systematic solutions have been proposed to support such a process. This article hypothesizes that a model-driven engineering (MDE) approach can help generate suitable user interfaces for elderly people, making the development process repeatable and allowing the systematic reuse of design knowledge about products for these end-users. To determine the validity of such hypothesis, the article presents the results of a case study where a healthcare supporting system for older adults, developed by using an MDE approach, was evaluated in four older adult care centers. The results obtained were highly positive, showing MDE as a possible path to address systematically the development of these applications.

Modelling ubiquitous collaborative systems that support people-driven processes represents a major challenge for software designers, since there is no a workflow that helps identify the scenarios in which the interaction among the participants could take place. Typically, this reduces the effectiveness of the resulting systems and increases the uncertainty during their developments. This paper proposes a visual modeling notation that allows designers to identify these potential interactions scenarios, and characterize them properly. The usability and expressiveness of this proposal was evaluated and compared to the most representative modeling notation reported in the literature to address this design challenge. The obtained results were highly positive, opening thus several opportunities to improve the design of ubiquitous collaborative systems.

While there have been important advances within wireless communication technology, the provision of communication support during disaster relief activities remains an open issue. The literature in disaster research reports several major restrictions to conducting first response activities in urban areas, given the limitations of telephone networks and radio systems to provide digital communication in the field. In search-and-rescue operations, the communication requirements are increased, since the first responders need to rely on real-time and reliable communication to perform their activities and coordinate their efforts with other teams. Therefore, these limitations open the door to improvisation during disaster relief efforts. In this paper, we argue that flying ad-hoc networks can provide the communication support needed in these scenarios, and propose a new solution towards that goal. The proposal involves the use of flying witness units, implemented using drones, that act as communication gateways between first responders working at different locations of the affected area. The proposal is named the Flying Real-Time Network, and its feasibility to provide communication in a disaster scenario is shown by presenting both a real-time schedulability analysis of message delivery, as well as simulations of the communication support in a physical scenario inspired by a real incident. The obtained results were highly positive and consistent, therefore this proposal represents a step forward towards the solution of this open issue.

Evaluating learning is a very important aspect of the teaching-learning process. Using collaborative techniques can lead to developing such important feelings as belonging to a group, acceptance and autonomy amongst students in formal education. The model being proposed here involved a combination of collaborative techniques for approaching how knowledge may be effectively evaluated.

This paper proposes a model-driven approach for developing high-level software interfaces that allow developers to interact with wearable devices easily. These components hide the heterogeneity of the devices interfaces and provide developers with a simple and homogeneous way to interoperate with these digital peripherals. The use of this approach also allows reducing risks and development efforts.

Underwater sensor networks represent an important and promising field of research due to the large diversity of underwater ubiquitous applications that can be supported by these networks, e.g., systems that deliver tsunami and oil spill warnings, or monitor submarine ecosystems. Most of these monitoring and warning systems require real-time communication in wide area networks that have a low density of nodes. The underwater communication medium involved in these networks is very harsh and imposes strong restrictions to the communication process. In this scenario, the real-time transmission of information is done mainly using acoustic signals, since the network nodes are not physically close. The features of the communication scenario and the requirements of the communication process represent major challenges for designers of both, communication protocols and monitoring and warning systems. The lack of models to represent these networks is the main stumbling block for the proliferation of underwater ubiquitous systems. This paper presents a real-time communication model for underwater acoustic sensor networks (UW-ASN) that are designed to cover wide areas with a low density of nodes, using any-to-any communication. This model is analytic, considers two solution approaches for scheduling the real-time messages, and provides a time-constraint analysis for the network performance. Using this model, the designers of protocols and underwater ubiquitous systems can quickly prototype and evaluate their solutions in an evolving way, in order to determine the best solution to the problem being addressed. The suitability of the proposal is illustrated with a case study that shows the performance of a UW-ASN under several initial conditions. This is the first analytic model for representing real-time communication in this type of network, and therefore, it opens the door for the development of underwater ubiquitous systems for several application scenarios.

Pervasive data sensing is a major issue that transverses various research areas and application domains. It allows identifying people’s behaviour and patterns without overwhelming the monitored persons. Although there are many pervasive data sensing applications, they are typically focused on addressing specific problems in a single application domain, making them difficult to generalize or reuse. On the other hand, the platforms for supporting pervasive data sensing impose restrictions to the devices and operational environments that make them unsuitable for monitoring loosely-coupled or fully distributed work. In order to help address this challenge this paper present a framework that supports distributed pervasive data sensing in a generic way. Developers can use this framework to facilitate the implementations of their applications, thus reducing complexity and effort in such an activity. The framework was evaluated using simulations and also through an empirical test, and the obtained results indicate that it is useful to support such a sensing activity in loosely-coupled or fully distributed work scenarios.

Underwater sensor networks are becoming an important field of research, because of their everyday increasing application scope. Examples of their application areas are environmental and pollution monitoring (mainly oil spills), oceanographic data collection, support for submarine geolocalization, ocean sampling and early tsunamis alert. The challenge of performing underwater communications is well known, provided that radio signals are useless in this medium, and a wired solution is too expensive. Therefore, the sensors in these networks transmit their information using acoustic signals that propagate well under water. This data transmission type not only brings an opportunity, but also several challenges to the implementation of these networks, e.g., in terms of energy consumption, data transmission and signal interference. In order to help advance the knowledge in the design and implementation of these networks for monitoring underwater spaces, this paper proposes a MAC protocol for acoustic communications between the nodes, based on a self-organized time division multiple access mechanism. The proposal was evaluated using simulations of a real monitoring scenario, and the obtained results are highly encouraging.

Este artículo propone un modelo instruccional colaborativo, para la enseñanza de las técnicas más comunes de evaluación de la usabilidad de interfaces de usuario. El modelo facilitó el trabajo colaborativo entre diversas universidades latinoamericanas, geográficamente dispersas, como un medio para transmitir conocimiento específico a estudiantes de pregrado en Ingeniería Informática y Ciencias de la Computación. Además del modelo instruccional colaborativo propuesto, el artículo presenta resultados experimentales obtenidos de su aplicación.