Sea Cage Gateway - A Distributed Sensor Management Network in ActorFrame
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This master thesis has been written in connection with the ongoing Sea Cage Gateway (SCG) project, a project investigating the possibility of remotely administering fish farming facilities. These facilities consist of sea cages placed offshore and connected to the mainland through wireless communication technologies. The sea cages all contain a number of sensors optimizing production and increasing safety. Not only must this sensor data be read, it must also be transported, collected, interpreted, handled, saved and retrieved. In addition, it is necessary to provide backup communication links in case of failures in the main communication systems. The system should be as autonomous as possible, allowing it to be unmanned for longer periods of time. This thesis has further investigated the possibility of remotely controlling and administering a fish farm through distributed nodes over wireless communication links. As a basis for this thesis domain descriptions from previous master theses written in connection with the SCG-project have been used. This thesis has also aimed to collect inspiration from other domains and concepts which have similarities with the SCG-project. With the increasing numbers of nodes and communication links present at the fish farm installations, areas such as grid computing and sensor networks have many applicable principles for the SCG-system. These principles have been integrated into the system design to give the basis for further such functionality in the SCG-domain. In addition to the areas of grid computing and sensor networks, the current and latest wireless communication technologies available for providing the services required by the SCG-system have been presented. The communication links also influence the system design since their connection types must be handled by the SCG-system elements. The SCG-system proposed has been designed and implemented with ActorFrame. The implemented system has functioned as a demonstrator for the main principles presented in the design. It has incorporated a GPS-receiver and a GPRS-modem to represent a sensor on a sea cage and a redundant communication link. The system implemented reports GPS-data to a central unit and issues alerts upon sensor data deviations (sea cage out of position). Furthermore, the demonstrator can detect a failed communication link and switch to the backup GPRS-modem, generate alarms, and continue to provide basic services. All elements and their status are reported and registered in a database and are presented through a dynamic web interface. The demonstrator has shown that ActorFrame can be utilized to provide the necessary functionality the SCG-domain requires. A few improvements are proposed for the framework to increase the flexibility and performance of the system, especially in the area of handling the distribution of actors on independent nodes and how the heterogeneous network technologies present in SCG-system require a higher-level of network-awareness on behalf of the application. This thesis has also suggested several possible extensions and future areas of work.