The development of a serious game requires perfect knowledge of the learning domain to obtain the desired results. But it is also true that this may not be enough to develop a successful serious game. First of all, the player has to feel that he is playing a game where the learning is only a consequence of the playing actions. Otherwise, the game is viewed as boring and not as a fun activity and engaging. For example, the player can catch some items in the scenario and then separate them according to its type (i.e., recycle them). Thus, the main action for player is catching the items in the scenario where the recycle action is a second action, which is viewed as a consequence of the first action. Sometimes, the game design relies on a detailed approach based on the ideas of the developers because some educational content are difficult to integrate in the games, while maintaining the fun factor in the first place. In this paper we propose a new methodology of design and development of serious games that facilitates the integration of educational contents in the games. Furthermore, we present a serious game, called “Clean World”, created using this new methodology.

In Vehicular Delay Tolerant Networks (VDTNs) an end-to-end relay path between bundles source and destination nodes may not be available. To accomplish such goal, VDTNs rely on nodes cooperation. Thus, in order to maintain the network efficiency, it is very important to ensure that all network nodes follow the protocol. This is not an easy task since nodes may diverge from the protocol due to a selfish behavior or to maintain their data or resources integrity. This paper proposes a cooperative watchdog system to detect and act against misbehavior nodes in order to reduce their impact in the overall network performance. Its operation relies on a cooperative exchange of nodes reputation along the network. By detecting selfish or misbehaving nodes, it is possible to improve the overall network performance. Conducted simulation experiments considering the VDTNSim tool and the Spray-and-Wait routing protocol shown that the cooperative watchdog proposed for VDTNs is not only effective in detecting misbehaving nodes but also contributes to improve the overall network performance by increasing the bundle delivery probability and decreasing the amount of resources waste.

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Vehicular Delay-Tolerant Networks emerge as a vehicular networks technology that can be deployed on a wide range of scenarios. For example, it can be applied in sparse and remote regions characterised by sparse connectivity to allow data communications, as well as in urban scenarios. Frequent network partitioning, intermittent connectivity, long propagation delays, high error rates and short contact durations characterise these environments. To overcome some of these issues, cooperation approaches should be considered to force nodes to share their own resources. It is important to perform this task because nodes may be unwilling to cooperate due to a selfish behaviour. Selfish nodes affect considerably the functionality and the performance of the overall network. This paper overviews the most relevant contributions on cooperation for vehicular networks. It also proposes four different cooperation strategies for Vehicular Delay-Tolerant Networks and studies their impact on the performance of the network. These strategies are enforced on two delay-tolerant networks routing protocols (Epidemic and Spray-and-Wait). Across all the experiments, it was shown that all the strategies contribute to the improvement of the overall network performance by increasing the bundle delivery probability and consequently decrease the bundle average delivery delay.

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In the last decade, both scientific community and automotive industry enabled communications among vehicles in different kinds of scenarios proposing different vehicular architectures. Vehicular delay-tolerant networks (VDTNs) were proposed as a solution to overcome some of the issues found in other vehicular architectures, namely, in dispersed regions and emergency scenarios. Most of these issues arise from the unique characteristics of vehicular networks. Contrary to delay-tolerant networks (DTNs), VDTNs place the bundle layer under the network layer in order to simplify the layered architecture and enable communications in sparse regions characterized by long propagation delays, high error rates, and short contact durations. However, such characteristics turn contacts very important in order to exchange as much information as possible between nodes at every contact opportunity. One way to accomplish this goal is to enforce cooperation between network nodes. To promote cooperation among nodes, it is important that nodes share their own resources to deliver messages from others. This can be a very difficult task, if selfish nodes affect the performance of cooperative nodes. This paper studies the performance of a cooperative reputation system that detects, identify, and avoid communications with selfish nodes. Two scenarios were considered across all the experiments enforcing three different routing protocols (First Contact, Spray and Wait, and GeoSpray). For both scenarios, it was shown that reputation mechanisms that punish aggressively selfish nodes contribute to increase the overall network performance.