Predation of shore crabs (Carcinus maenas (L)) and starfish (Asterias rubens L.) on blue mussel (Mytilus edulis L.) seed from wild sources and spat collectors

In The Netherlands, several pilot projects are carried out on the use of spat collectors as an additional supply of seed for bottom culture of mussels (Mytilus edulis). The method proves to be successful in yielding substantial amounts of seed. One of the conditions for successful application of collector seed on bottom plots is a good yield of the seed on bottom plots. Mussel seed of different origin (from wild littoral and sublittoral beds or from collectors) was offered to predators (crabs Carcinus maenas and starfish Asterias rubens) and seed survival was monitored. In addition, the effect of density and size of collector seed on predation was studied. Circular cages containing predators and seed were placed in a basin with running seawater, or suspended from a jetty in a harbour. Two size classes of predators and three size classes of seed were used. Survival was monitored. Consumption of mussel seed by starfish was much lower than by crabs. Maximum observed consumption rates were 23 seed/day/crab and 1 seed/day/starfish. Consumption rates increased significantly with decreasing seed size. Seed larger than 20 mm were consumed at a significantly lower rate. Seed density did not affect survival. Collector seed was not consumed at higher rates than wild littoral or sublittoral seed. In conclusion, collector seed can be a promising additional source of seed for bottom culture of mussels in The Netherland

Growing plants without soil for experimental use /

no.125

A virtual reality application for aggression de-escalation training in public transport

Item does not contain fulltextTo train public transport employees to deal with aggressive passengers, simulation-based training can be a cost-effective instrument. Within this research a virtual reality training application for bus drivers has been developed. The application consists of 10 different scenarios that can be used to practice how to act during confrontations with aggressive passengers. During each scenario, the user will have a conversation through text and pre-recorded sentences with an intelligent virtual agent. In addition, during the training the user will have to determine the kind of aggression that is shown by the passenger, choose the right communication style and decide whether or not to report the incident at the end of the scenario. This paper describes the full development of the application and the scenarios, as well as the first experiences reported during a pilot study. Suggestions for improvement and future work are discussed.BNAIC 2018: 30th Benelux Conference on Artificial Intelligence, 's Hertogenbosch, The Netherlands, 8-9 November 201

A virtual reality application for aggression de-escalation training in public transport

To train public transport employees to deal with aggressive passengers, simulation-based training can be a cost-effective instrument. Within this research a virtual reality training application for bus drivers has been developed. The application consists of 10 different scenarios that can be used to practice how to act during confrontations with aggressive passengers. During each scenario, the user will have a conversation through text and pre-recorded sentences with an intelligent virtual agent. In addition, during the training the user will have to determine the kind of aggression that is shown by the passenger, choose the right communication style and decide whether or not to report the incident at the end of the scenario. This paper describes the full development of the application and the scenarios, as well as the first experiences reported during a pilot study. Suggestions for improvement and future work are discussed

Virtually bad: A study on virtual agents that physically threaten human beings

Item does not contain fulltextThis paper introduces the concept of "virtual bad guys": intelligent virtual agents that take a negative or even aggressive stance towards the user. Although they pave the way to various interesting applications, it is hard to create virtual bad guys that are taken seriously by the user, since they are typically unable to apply serious sanctions. To address this issue, this study experimentally investigated the effect of "consequential" agents that are able to physically threaten their human interlocutors. A consequential agent was developed by equipping users with a (non-functioning) device, through which they were made to believe the agent could mildly shock them. Effects on participants' levels of anxiety and (physiological and self-reported) stress were measured, and the role of presence and perceived believability of the virtual agent was assessed. The consequential agent triggered a stronger physiological stress response than the non-consequential agent, whereas self-reported levels of anxiety and stress did not significantly differ. Furthermore, while presence and believability were substantially associated with users' stress response, both states did not mediate or explain the effect of a consequential vs. non-consequential agent on stress, as they did not significantly differ between conditions. Implications of these findings and suggestions for follow-up studies on "virtual bad guys" are discussed.17th International Conference on Autonomous Agents and MultiAgent Systems (Stockholm, Sweden - July 10 - 15, 2018

A virtual reality application for aggression de-escalation training in public transport

To train public transport employees to deal with aggressive passengers, simulation-based training can be a cost-effective instrument. Within this research a virtual reality training application for bus drivers has been developed. The application consists of 10 different scenarios that can be used to practice how to act during confrontations with aggressive passengers. During each scenario, the user will have a conversation through text and pre-recorded sentences with an intelligent virtual agent. In addition, during the training the user will have to determine the kind of aggression that is shown by the passenger, choose the right communication style and decide whether or not to report the incident at the end of the scenario. This paper describes the full development of the application and the scenarios, as well as the first experiences reported during a pilot study. Suggestions for improvement and future work are discussed

Virtually bad: A study on virtual agents that physically threaten human beings

This paper introduces the concept of "virtual bad guys": intelligent virtual agents that take a negative or even aggressive stance towards the user. Although they pave the way to various interesting applications, it is hard to create virtual bad guys that are taken seriously by the user, since they are typically unable to apply serious sanctions. To address this issue, this study experimentally investigated the effect of "consequential" agents that are able to physically threaten their human interlocutors. A consequential agent was developed by equipping users with a (non-functioning) device, through which they were made to believe the agent could mildly shock them. Effects on participants' levels of anxiety and (physiological and self-reported) stress were measured, and the role of presence and perceived believability of the virtual agent was assessed. The consequential agent triggered a stronger physiological stress response than the non-consequential agent, whereas self-reported levels of anxiety and stress did not significantly differ. Furthermore, while presence and believability were substantially associated with users' stress response, both states did not mediate or explain the effect of a consequential vs. non-consequential agent on stress, as they did not significantly differ between conditions. Implications of these findings and suggestions for follow-up studies on "virtual bad guys" are discussed