Smart embedded objects will become an important part of what is called the Internet of Things. However, the integration of embedded devices into the Internet introduces several challenges, since many of the existing Internet technologies and protocols were not designed for this class of devices. In the past few years, there have been many efforts to enable the extension of Internet technologies to constrained devices. Initially, this resulted in proprietary protocols and architectures. Later, the integration of constrained devices into the Internet was embraced by IETF, moving towards standardized IP-based protocols. In this paper, we will briefly review the history of integrating constrained devices into the Internet, followed by an extensive overview of IETF standardization work in the 6LoWPAN, ROLL and CoRE working groups. This is complemented with a broad overview of related research results that illustrate how this work can be extended or used to tackle other problems and with a discussion on open issues and challenges. As such the aim of this paper is twofold: apart from giving readers solid insights in IETF standardization work on the Internet of Things, it also aims to encourage readers to further explore the world of Internet-connected objects, pointing to future research opportunities.

Networks of smart resource-constrained objects, such as sensors and actuators, can support a wide range of application domains. In most cases these networks were proprietary and stand-alone. More recently, many efforts have been undertaken to connect these networks to the Internet using standard protocols. Current solutions that integrate smart resource-constrained objects into the Internet are mostly gateway-based. In these solutions, security, firewalling, protocol translations and intelligence are implemented by gateways at the border of the Internet and the resource-constrained networks. In this paper, we introduce a complementary approach to facilitate the realization of what is called the Internet of Things. Our approach focuses on the objects, both resource-constrained and non-constrained, that need to cooperate by integrating them into a secured virtual network, named an Internet of Things Virtual Network or IoTVN. Inside this IoT-VN full end-to-end communication can take place through the use of protocols that take the limitations of the most resource-constrained devices into account. We describe how this concept maps to several generic use cases and, as such, can constitute a valid alternative approach for supporting selected applications. A first implementation demonstrating the key concepts of this approach is described. It illustrates the feasibility of integrating resource-constrained devices into virtual networks, but also reveals open challenges.

The Internet of Things (IoT) is expanding rapidly to new domains in which embedded devices play a key role and gradually outnumber traditionally-connected devices. These devices are often constrained in their resources and are thus unable to run standard Internet protocols. The Constrained Application Protocol (CoAP) is a new alternative standard protocol that implements the same principals as the Hypertext Transfer Protocol (HTTP), but is tailored towards constrained devices. In many IoT application domains, devices need to be addressed in groups in addition to being addressable individually. Two main approaches are currently being proposed in the IoT community for CoAP-based group communication. The main difference between the two approaches lies in the underlying communication type: multicast versus unicast. In this article, we experimentally evaluate those two approaches using two wireless sensor testbeds and under different test conditions. We highlight the pros and cons of each of them and propose combining these approaches in a hybrid solution to better suit certain use case requirements. Additionally, we provide a solution for multicast-based group membership management using CoAP.

Smart embedded objects will become an important part of what is called the Internet of Things. Applications often require concurrent interactions with several of these objects and their resources. Existing solutions have several limitations in terms of reliability, flexibility and manageability of such groups of objects. To overcome these limitations we propose an intermediately level of intelligence to easily manipulate a group of resources across multiple smart objects, building upon the Constrained Application Protocol (CoAP). We describe the design of our solution to create and manipulate a group of CoAP resources using a single client request. Furthermore we introduce the concept of profiles for the created groups. The use of profiles allows the client to specify in more detail how the group should behave. We have implemented our solution and demonstrate that it covers the complete group life-cycle, i.e., creation, validation, flexible usage and deletion. Finally, we quantitatively analyze the performance of our solution and compare it against multicast-based CoAP group communication. The results show that our solution improves reliability and flexibility with a trade-off in increased communication overhead.

Electronic waste is presently acknowledged as the rapidly expanding waste stream on a global scale. Consequently, e-waste represents a primary global concern in modern society since electronic equipment contains hazardous substances, and if not managed properly, it will harm human health and the environment. Thus, the necessity for more innovative, safer, and greener systems to handle e-waste has never been more urgent. To address this issue, a smart e-waste management system based on the Internet of Things (IoT) and Deep Learning (DL) based object detection is designed and developed in this paper. Three state-of-the-art object detection models, namely YOLOv5s, YOLOv7-tiny and YOLOv8s, have been adopted in this study for e-waste object detection. The results demonstrate that YOLOv8s achieves the highest mAP@50 of 72% and map@50-95 of 52%. This innovative system offers the potential to manage e-waste more efficiently, supporting green city initiatives and promoting sustainability. By realizing an intelligent green city vision, we can tackle various contamination problems, benefiting both humans and the environment.

Smart embedded objects such as sensors and actuators will become an important part of the Internet of Things. With recent technologies, it has now become possible to deploy a sensor network and interconnect it with IPv6 Internet. However, several manual configuration steps are still needed to integrate a sensor network within an existing networking environment. In this paper we describe a novel self-organization solution to facilitate the deployment of sensor networks and enable the discovery, end-to-end connectivity and service usage of these newly deployed sensor nodes. The proposed approach makes use of embedded web service technology, i.e. the IETF Constrained Application Protocol (CoAP). Automatic hierarchical discovery of CoAP servers is one of the key features, resulting in a brows able hierarchy of CoAP servers, up to the level of the sensor resources, which can be accessed both over CoAP and HTTP and through the use of either DNS names or IPv6 addresses. To demonstrate the feasibility of our approach we have implemented the solution and deployed it on a test setup, which is publicly accessible to everyone.