The challenge of making sense of data collected in the Internet of Things (IoT), such that the “needle” can be found in the digital haystack, is the focus of this work. This is a significant area of research in the next phase of IoT development, to allow the IoT potential to be more fully achieved; the envisaged IoT is not currently being exploited due to limited hardware and software developments. This results in challenges related to the collection of data from smart cities and its organization, recognition, and use. Currently, these operations do not take place in a standardized way, resulting in ad hoc device- and application-specific deployments. Furthermore, as the IoT continues to evolve, the achievement of a cohesive, interoperable, and global system becomes increasingly unlikely.

The authors present this work from a largely nontechnical viewpoint, and it is therefore accessible to a wide reader base. A more technical discussion could, however, help to reinforce existing challenges. As an example of a lack of technicality, the authors state generally that the collected data will be “in high demand.” This statement could, however, be further contextualized: The Netherlands Organization for Applied Scientific Research (TNO) has released the smart appliances reference (SAREF) ontology, for example, which collects data on smart appliances in buildings. Context may be collected using the SAREF model on washing machines, light switches, and smoke sensors in a building: Do the authors consider such data will be “in high demand”? By way of contrast, information on bicycle availability in Barcelona is likely to be more widely demanded, as is information on road congestion levels. It would therefore have been helpful for the authors to be more specific in their presentation of the subject material and, in relation to this specific example, contextualize the scope of “high demand,” particularly because of the subsequent impact on the execution of discovery processes.

There are many questions arising from this work, but these are likely to be covered in separate research papers given the scale of each new IoT research area. For example, what are the operational requirements of a technical infrastructure supporting the IoT? What are the requirements of a consolidated ontology that allows global availability of interoperable data? It would also be interesting to learn specific details regarding standardization processes underway by the IEEE, ITU, and ISO in support of the envisaged IoT due to the important role that they should eventually play in its design and operation.