Occlusion-based cooperative transport with a swarm of miniature mobile robots

This paper proposes a strategy for transporting a large object to a goal using a large number of mobile robots that are significantly smaller than the object. The robots only push the object at positions where the direct line of sight to the goal is occluded by the object. This strategy is fully decentralized and requires neither explicit communication nor specific manipulation mechanisms. We prove that it can transport any convex object in a planar environment. We implement this strategy on the e-puck robotic platform and present systematic experiments with a group of 20 e-pucks transporting three objects of different shapes. The objects were successfully transported to the goal in 43 out of 45 trials. When using a mobile goal, teleoperated by a human, the object could be navigated through an environment with obstacles. We also tested the strategy in a 3-D environment using physics-based computer simulation. Due to its simplicity, the transport strategy is particularly suited for implementation on microscale robotic systems

Traditional use of shore platforms:a study of the artisanal management of salinas on the Maltese Islands (Central Mediterranean)

Shore platforms and salinas in the Mediterranean region have a long-standing relationship, rooted in the traditional practice of salt making. On small islands with limited natural resources, the production of salt from seawater, through insolation and intense human endeavour, offered numerous economic benefits. Salt has been a foremost natural resource for millennia with a range of uses from preserving edible foods to cooking, cleaning, laundry, and hygiene, and for medicinal uses in dilute solutions. Within the Maltese Islands, this traditional activity was developed primarily on the soft limestone shore platforms situated along low-lying rocky coasts. Although coastal production has declined in number over the years, a few salinas have persisted in their artisanal practice and are becoming a cultural geo-heritage attraction. The aim of this article is to explore the multiple geographies of this industry on two shore platforms by examining the complicated relationships that have emerged and molded between the physical landscape and human culture. Mapping out these relations through the traditional but complex management systems at two salinas, that is, the salinas at Delimara Point (Malta) and those at Xwejni Bay (Gozo), highlights the delicate nature of these relations as well as the need to support them in order to continually reproduce the cultural micro-landscape. The resultant micro-landscape is becoming an increasingly important living expression of the cultural geo-heritage of the Maltese Islands, which requires careful understanding and management of these relations if it is to be maintained as a vibrant geo-tourist attraction.peer-reviewe

Can web crawlers revolutionize ecological monitoring?

Despite recent advances, ecosystem service monitoring is limited by insufficient data, the complexity of social-ecological systems, and poor integration of information that tracks changes in ecosystems and economic activities. However, new information and communication technologies are revolutionizing the generation of, and access to, such data. Can researchers who are interested in ecological monitoring tap into these increased flows of information by "mining" the internet to detect "early-warning" signs that may signal abrupt ecological changes? Here, we explore the possibility of using web crawlers and internet-based information to complement conventional ecological monitoring, with a special emphasis on the prospects for avoiding "late warnings"-that is, when ecosystems have already shifted to less desirable states. Using examples from coral reef ecosystems, we explore the untapped potential, as well as the limitations, of relying on web-based information to monitor ecosystem services and forewarn us of negative ecological shifts.</p

Finding consensus without computation

A canonical problem for swarms of agents is to collectively choose one of multiple options in their environment. We present a novel control strategy for solving this problem-the first to be free of arithmetic computation. The agents do not communicate with each other nor do they store run-time information. They have a line-of-sight sensor that extracts one ternary digit of information from the environment. At every time step, they directly map this information onto constant-value motor commands. We evaluate the control strategy with both simulated and physical e-puck robots. By default, the robots are expected to choose, and move to, one of two options of equal value. The simulation studies show that the strategy is robust against sensory noise, scalable to large swarm sizes, and generalizes to the problems of choosing between more than two options or between unequal options. The experiments-50 trials conducted with a group of 20 e-puck robots-show that the group achieves consensus in 96% of the trials. Given the extremely low hardware requirements of the strategy, it opens up new possibilities for the design of swarms of robots that are small in size (≪10 -3 m) and large in numbers (≫10 3 )

Breaking bad news in cancer : an assessment of Maltese patients’ preferences

Purpose: It is unclear whether Maltese cancer patients wish to know their diagnosis or to what extent they want to be informed. The aim was to assess patients’ preferences for receiving a cancer diagnosis and being involved in the decision-making process, and then compare these with results from similar international studies. Methods: Two hundred fifty-two Maltese adult cancer patients were invited to complete two standardised tools: the Measure of Patients’ Perspective (MPP), assessing patients’ preferences for receiving news about their cancer, and the Control Preferences Scale (CPS), examining involvement in decision-making. Results: Maltese patients rated the ‘content’ subscale (information given; mean 4.17, SD 0.59) as significantly more important (p<0.001) than ‘support’ (offering comfort/support; mean 3.73, SD 0.68) and ‘facilitation’ (how information is given; mean 3.86, SD 0.68). Patients with higher levels of education had significantly higher scores for ‘content’ (p=0.018) and ‘facilitation’ (p<0.001) on the MPP, while lower education levels preferred a passive role (p=0.01) on the CPS. Although there is a trend towards a collaborative and even an active role in treatment decisions, patients still exhibit a paternalistic attitude towards their physician. Age, gender and medical variables had no significant influence on response. Conclusions: Maltese cancer patients want to be informed of their cancer diagnosis, its treatment and prognosis, similar to other international studies. However, 60% of Maltese patients prefer a more paternalistic approach towards their physician when compared to other studies.peer-reviewe

Human-robot swarm interaction with limited situational awareness

This paper studies how an operator with limited situational awareness can collaborate with a swarm of simulated robots. The robots are distributed in an environment with wall obstructions. They aggregate autonomously but are unable to form a single cluster due to the obstructions. The operator lacks the bird’s-eye perspective, but can interact with one robot at a time, and influence the behavior of other nearby robots. We conducted a series of experiments. They show that untrained participants had marginal influence on the performance of the swarm. Expert participants succeeded in aggregating 85% of the robots while untrained participants, with bird’s-eye view, succeeded in aggregating 90%. This demonstrates that the controls are sufficient for operators to aid the autonomous robots in the completion of the task and that lack of situational awareness is the main difficulty. An analysis of behavioral differences reveals that trained operators learned to gain superior situational awareness