# Search and Rescue in a Maze-like Environment with Ant and Dijkstra Algorithms
## 6 Conclusions and Future Work
### Future Work  
In Section 4.1.1, we stated that we simplified the computation and implementation of the system by discretizing a grid method similar to the one used in [72]. Naturally, future work would address the situations in which the number of agents (swarm size) and the size of the grid unit are not equal and provide problem specifications to the community that could be used as benchmark data sets for future work.  
Furthermore, as stated in the introduction, the simulation is a 2D representation of the world. Extending this to a 3D model (both for the signal propagation through obstacles, as well as with the layout and structure of the building in mind), will be subject to an application-driven need to do so. The presented implementation and performance evaluation suffice to argue for the approach _in theory_; a real-world implementation will have to address a number of engineering issues, as well accounting for the 3D nature of the world. As we acknowledged before, there is a very active community working on all sorts of approaches related to, e.g., path finding for multiple devices [110], collision-free movement of a swarm [26], movement in formation [27] or through narrow spaces or bottlenecks [111]. Whether it be in 2D or 3D, we fully expect that any deployed solution using our approach will consist of a merger of multiple techniques, tailored to the specific problem at hand [112]. As we discuss in [15], applying nature-inspired solutions _for the sake of it_, while popular, is problematic. Future work will consider the practical aspects of implementing and deploying our solution for a swarm of UAVs, and will certainly reflect on the way in which the benefits of our approach can best be combined with both  
Figure 20: A summary view of the SAR process in two phases. The search starts with a victim being trapped in the maze-like environment, broadcasting an SOS signal. In Phase-I, the search agents explore the environment in search of the SOS signal, using iAA algorithm. After locating the source of SOS signal, the agents switch to Phase-II, and find the shortest routing path to communicate information about the victim’s location to the base station. The remaining unused agents (marked in gray) can return to the base station.  
nature-inspired [113] as well as other, non-nature-inspired approaches so as to optimize performance.  
Finally, in future work, we would like to allocate some time to investigate the complexity of the mazes further. Preliminary investigations in which we compared optimal path lengths in randomly created mazes yielded results that informed the work presented in this article; however, the results themselves were omitted, mainly for the sake of brevity. A real-world study of mazes and operational environments for SAR swarms is required for work targeting the actual deployment of a drone swarm.  
Conceptualization and Methodology: D.R., A.F.I. and F.S.; Software and validation: Z.H., A.A.Z., D.R. and A.F.I.; Formal Analysis: Z.H., A.A.Z., D.R., F.S., H.H. and A.F.I.; Investigation: Z.H., A.A.Z., D.R., H.H. and A.F.I; Data curation: Z.H., A.A.Z., D.R., F.S., H.H. and A.F.I.; Writing--original draft preparation: [PERSON], [PERSON] and [PERSON]; Writing--review and editing: [PERSON], [PERSON], [PERSON], [PERSON], [PERSON] and A.F.I.; Visualization: [PERSON], [PERSON], A.F.I. and [PERSON]; Supervision: [PERSON]; Project Administration: [PERSON] and D.R.; Funding acquisition: [PERSON], A.F.I. All authors have read and agreed to the published version of the manuscript. We acknowledge the UAE 2013 ICTFund grant \"Bio-inspired Self-organizing Networks\". Data Availability Statement: Data are available upon reasonable request from the corresponding author. We thank [PERSON] (KUST) for his advice about path loss models. We thank [PERSON] (Universite Libre de Bruxelles) and [PERSON] (KUST) on encouraging exchanges. A.F.I. thanks Cornell University for the hospitality during a part of this project. The authors declare no conflict of interest.