J. Sens. Actuator Netw.2016, 5(2), 8; doi:10.3390/jsan5020008 - published 22 April 2016 Show/Hide Abstract
Abstract: Most existing dissemination schemes in Mobile Social Networks (MSNs) only consider the data dissemination. However, there are two types of messages: data and the control message (i.e., acknowledgment) in MSNs, and receiving acknowledgment is very important in many applications (e.g., the mobile trade and the incentive mechanism). In order to maximize the desired message delivery ratio, we have to identify the priority of each message in the network during the limited contact opportunity. Therefore, we propose a generic priority-based compare-split routing scheme, which proves to be the optimal buffer exchange strategy. During each contact opportunity, relays compare their forwarding abilities to different destinations based on two types of criteria: the contact probability and the social status. Ideally, each relay keeps the messages whose destinations meet the current relay frequently. Then, an adaptive priority-based exchange scheme, which considers the priority within each type of messages and the relative priority between two types of messages, is proposed to exchange the most benefit messages. The effectiveness of our scheme is verified through extensive simulations in synthetic and real traces.
J. Sens. Actuator Netw.2016, 5(2), 7; doi:10.3390/jsan5020007 - published 2 April 2016 Show/Hide Abstract
Abstract: Smart devices and cyber-physical systems, which are interconnected to IT systems and services, form the basis for the arising Internet of Everything, opening up new economic opportunities for its participants and users beyond its technological aspects and challenges. While today’s e-business scenarios are mostly dominated by a few centralized online platforms, future business models, which will be feasible for the Internet of Everything, need to address special requirements. Such business models, e.g., leveraging the possibilities of smart cities, need to cope with arbitrary combinations of products and services orchestrated into complex products in a highly distributed and dynamic environment. Furthermore, these arbitrary combinations are influenced by real-time context information derived from sensor networks or IT systems, as well as the users’ requirements and preferences. The complexity of finding the optimal product/service combination overstrains users and leads to decisions according to the principle of adverse selection (i.e., choosing good enough instead of optimal). Such e-business models require an appropriate underlying value generation architecture that supports users in this process. In this paper, we develop a business model that addresses these problems. In addition, we present the Distributed Market Spaces (DMS) software-system architecture as a possible implementation, which enables the aforementioned decentralized and context-centric e-business scenario and leverages the commercial possibilities of smart cities.
J. Sens. Actuator Netw.2016, 5(2), 6; doi:10.3390/jsan5020006 - published 29 March 2016 Show/Hide Abstract
Abstract: In this paper, we propose a reference architecture for Delay-Tolerant Networking (DTN) routing protocols and a thorough quantitative evaluation of many protocols proposed in the literature. We categorize DTN protocols according to their use of the three techniques that are the key elements of our reference architecture: queue management, forwarding and replication. Queue management orders and manages the messages in the node’s buffer; forwarding selects the messages to be delivered when there is a contact; and finally, replication bounds the number of replicas in the network. Contrary to most previous papers, where either only qualitative comparisons have been presented or only a single category of protocols has been analyzed, in our work, we discuss the results of our experimental activity on many of the DTN protocols in the literature. Our results, which have been obtained both using synthetic and real mobility traces, show that an effective combination of the proposed techniques can significantly improve the performance of the protocols in terms of delivery ratio, overhead and delay.
J. Sens. Actuator Netw.2016, 5(1), 5; doi:10.3390/jsan5010005 - published 3 March 2016 Show/Hide Abstract
Abstract: Over the last years, we have witnessed increasing interconnection between the physical and digital world. The so called Internet of Things (IoT) is becoming more and more a reality in application domains like manufacturing, mobile computing, transportation, and many others. However, despite promising huge potential, the application domain of smart homes is still at its infancy and lags behind other fields of IoT. A deeper understanding of this type of techno-human system is required to make this vision a reality. In this paper, we report findings from a three year pilot that sheds light on the challenges of leveraging IoT technology in the home environment. In particular, we provide details on data quality issues in real-world deployments. That is, we analyze application level data for errors in measurements as well as issues in the end-to-end communication. Understanding what data errors to expect is crucial for understanding the smart building domain and paramount for building successful applications. With our work, we provide insights in a domain of IoT that has tremendous growth potential and help researchers as well as practitioners to better account for the data characteristics of smart homes.
J. Sens. Actuator Netw.2016, 5(1), 4; doi:10.3390/jsan5010004 - published 19 February 2016 Show/Hide Abstract
Abstract: Contiki’s Cooja is a very popular wireless sensor network (WSN) simulator, but it lacks support for modelling sensing coverage, focusing instead on network connectivity and protocol performance. However, in practice, it is the ability of a sensor network to provide a satisfactory level of coverage that defines its ultimate utility for end-users. We introduce WSN-Maintain, a Cooja-based tool for coverage and network lifetime evaluation in an in-building WSN. To extend the network lifetime, but still maintain the required quality of coverage, the tool finds coverage redundant nodes, puts them to sleep and automatically turns them on when active nodes fail and coverage quality decreases. WSN-Maintain together with Cooja allow us to evaluate different approaches to maintain coverage. As use cases to the tool, we implement two redundant node algorithms: greedy-maintain, a centralised algorithm, and local-maintain, a localised algorithm to configure the initial network and to turn on redundant nodes. Using data from five real deployments, we show that our tool with simple redundant node algorithms and reading correlation can improve energy efficiency by putting more nodes to sleep.
J. Sens. Actuator Netw.2016, 5(1), 3; doi:10.3390/jsan5010003 - published 6 February 2016 Show/Hide Abstract
Abstract: Digital devices are becoming increasingly ubiquitous and interconnected. Their evolution to intelligent parts of a digital ecosystem creates novel applications with so far unresolved security issues. A particular example is a vehicle. As vehicles evolve from simple means of transportation to smart entities with new sensing and communication capabilities, they become active members of a smart city. The Internet of Vehicles (IoV) consists of vehicles that communicate with each other and with public networks through V2V (vehicle-to-vehicle), V2I (vehicle-to-infrastructure) and V2P (vehicle-to-pedestrian) interactions, which enables both the collection and the real-time sharing of critical information about the condition on the road network. The Social Internet of Things (SIoT) introduces social relationships among objects, creating a social network where the participants are not humans, but intelligent objects. In this article, we explore the concept of the Social Internet of Vehicles (SIoV), a network that enables social interactions both among vehicles and among drivers. We discuss technologies and components of the SIoV, possible applications and issues of security, privacy and trust that are likely to arise.