Long-Term Map Maintenance in Complex Environments

2021 ◽  
pp. 146-161
Author(s):  
Josias Oliveira ◽  
Filipe Mutz ◽  
Avelino Forechi ◽  
Pedro Azevedo ◽  
Thiago Oliveira-Santos ◽  
...  
2020 ◽  
Author(s):  
Vardhman Kumar ◽  
Ung Hyun Ko ◽  
Yilong Zhou ◽  
Jiaul Hoque ◽  
Gaurav Arya ◽  
...  

Recent advancements in soft robotics have led to the development of compliant robots that can exhibit complex motions driven by living cells(1, 2), chemical reactions(3), or electronics(4). Further innovations are however needed to create the next generation of soft robots that can carry out advanced functions beyond locomotion. Here we describe DraBot—a dragonfly-inspired, entirely soft, multifunctional robot that combines long-term locomotion over water surface with sensing, responding, and adaptation capabilities. By integrating soft actuators, stimuli-responsive materials, and microarchitectural features, we created a circuitry of pneumatic and microfluidic logic that enabled the robot to undergo user- and environment-controlled (pH) locomotion, including navigating hazardous (acidic) conditions. DraBot was also engineered to sense additional environmental perturbations (temperature) and detect and clean up chemicals (oil). The design, fabrication, and integration strategies demonstrated here pave a way for developing futuristic soft robots that can acclimatize and adapt to harsh conditions while carrying out complex tasks such as exploration, environmental remediation, and health care in complex environments.


Author(s):  
George Veletsianos ◽  
Aaron Doering

<span>In this paper we investigate the experiences of elementary school children over a two-year period during which they engaged with a hybrid Adventure Learning program. In addition to delineating Adventure Learning experiences, we report on educational technology implementations in ecologically valid and complex environments, while drawing inferences on the design of sustainable and successful innovations. Our research indicates that the Adventure Learning experience over the two-year period was dynamic, participatory, engaging, collaborative, and social. Students eagerly became part of the experience both inside and outside of the classroom, and it quickly became apparent that they saw themselves as valued members of the unfolding storyline that mediated their learning. Our recommendations for future research and practice include a call to evaluate "authenticity," focus on the learner experience and narrative, and consider the interplay between pedagogy, technology, and design.</span>


2019 ◽  
Vol 38 (12-13) ◽  
pp. 1442-1462 ◽  
Author(s):  
Zakary Littlefield ◽  
David Surovik ◽  
Massimo Vespignani ◽  
Jonathan Bruce ◽  
Weifu Wang ◽  
...  

Tensegrity-based robots can achieve locomotion through shape deformation and compliance. They are highly adaptable to their surroundings, and are lightweight, low cost, and physically robust. Their high dimensionality and strongly dynamic nature, however, can complicate motion planning. Efforts to date have primarily considered quasi-static reconfiguration and short-term dynamic motion of tensegrity robots, which do not fully exploit the underlying system dynamics in the long term. Longer-horizon planning has previously required costly search over the full space of valid control inputs. This work synthesizes new and existing approaches to produce dynamic long-term motion while balancing the computational demand. A numerical process based upon quasi-static assumptions is first applied to deform the system into an unstable configuration, causing forward motion. The dynamical characteristics of the result are then altered via a few simple parameters to produce a small but diverse set of useful behaviors. The proposed approach takes advantage of identified symmetries on the prototypical spherical tensegrity robot, which reduce the number of needed gaits but allow motion along different directions. These gaits are first combined with a standard search method to achieve long-term planning in environments where the developed gaits are effective. For more complex environments, the various motion primitives are paired with the fall-back option of random valid actions and are used by an informed sampling-based kinodynamic motion planner with anytime properties. Evaluations using a physics-based model for the prototypical robot demonstrate that modest but efficiently applied search effort can unlock the utility of dynamic tensegrity motion to produce high-quality solutions.


2010 ◽  
Vol 109 (5) ◽  
pp. 201-206 ◽  
Author(s):  
David M. Zirkle ◽  
Arthur K. Ellis
Keyword(s):  

2020 ◽  
Author(s):  
Karin E. Kram ◽  
Autumn Henderson ◽  
Steven E. Finkel

AbstractMicrobes live in complex and consistently changing environments, but it is difficult to replicate this in the laboratory. Escherichia coli has been used as a model organism in experimental evolution studies for years; specifically, we and others have used it to study evolution in complex environments by incubating the cells into long-term stationary phase (LTSP) in rich media. In LTSP, cells experience a variety of stresses and changing conditions. While we have hypothesized that this experimental system is more similar to natural environments than some other lab conditions, we do not yet know how cells respond to this environment biochemically or physiologically. In this study, we begin to unravel the cells’ responses to this environment by characterizing the transcriptome of cells during LTSP. We found that cells in LTSP have a unique transcriptional program, and that several genes are uniquely upregulated or downregulated in this phase. Further, we identified two genes, cspB and cspI, which are most highly expressed in LTSP, even though these genes are primarily known to respond to cold-shock. When competed with wild-type cells, these genes are also important for survival during LTSP. These data allow us to compare biochemical responses to multiple environments and identify useful model systems, identify gene products that may play a role in survival in this complex environment, and identify novel functions of proteins.ImportanceExperimental evolution studies have elucidated evolutionary processes, but usually in chemically well-defined and/or constant environments. Using complex environments is important to begin to understand how evolution may occur in natural environments, such as soils or within a host. However, characterizing the stresses cells experience in these complex environments can be challenging. One way to approach this is by determining how cells biochemically acclimate to heterogenous environments. In this study we begin to characterize physiological changes by analyzing the transcriptome of cells in a dynamic complex environment. By characterizing the transcriptional profile of cells in long-term stationary phase, a heterogenous and stressful environment, we can begin to understand how cells physiologically and biochemically react to the laboratory environment, and how this compares to more natural conditions.


2021 ◽  
Author(s):  
Mirko Klukas ◽  
Sugandha Sharma ◽  
Yilun Du ◽  
Tomas Lozano-Perez ◽  
Leslie Pack Kaelbling ◽  
...  

When animals explore spatial environments, their representations often fragment into multiple maps. What determines these map fragmentations, and can we predict where they will occur with simple principles? We pose the problem of fragmentation of an environment as one of (online) spatial clustering. Taking inspiration from the notion of a "contiguous region" in robotics, we develop a theory in which fragmentation decisions are driven by surprisal. When this criterion is implemented with boundary, grid, and place cells in various environments, it produces map fragmentations from the first exploration of each space. Augmented with a long-term spatial memory and a rule similar to the distance-dependent Chinese Restaurant Process for selecting among relevant memories, the theory predicts the reuse of map fragments in environments with repeating substructures. Our model provides a simple rule for generating spatial state abstractions and predicts map fragmentations observed in electrophysiological recordings. It further predicts that there should be "fragmentation decision" or "fracture" cells, which in multicompartment environments could be called "doorway" cells. Finally, we show that the resulting abstractions can lead to large (orders of magnitude) improvements in the ability to plan and navigate through complex environments.


BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Andrey N. Shkoporov ◽  
Ekaterina V. Khokhlova ◽  
Niamh Stephens ◽  
Cara Hueston ◽  
Samuel Seymour ◽  
...  

Abstract Background The crAss-like phages are ubiquitous and highly abundant members of the human gut virome that infect commensal bacteria of the order Bacteroidales. Although incapable of lysogeny, these viruses demonstrate long-term persistence in the human gut microbiome, dominating the virome in some individuals. Results Here we show that rapid phase variation of alternate capsular polysaccharides in Bacteroides intestinalis cultures plays an important role in a dynamic equilibrium between phage sensitivity and resistance, allowing phage and bacteria to multiply in parallel. The data also suggests the role of a concomitant phage persistence mechanism associated with delayed lysis of infected cells, similar to carrier state infection. From an ecological and evolutionary standpoint, this type of phage-host interaction is consistent with the Piggyback-the-Winner model, which suggests a preference towards lysogenic or other “benign” forms of phage infection when the host is stably present at high abundance. Conclusion Long-term persistence of bacteriophage and host could result from mutually beneficial mechanisms driving bacterial strain-level diversity and phage survival in complex environments.


Author(s):  
Lai Ling Ng ◽  
Jon Pemberton

Globalisation, liberalisation of trade, internationalisation of financial markets, and the information technology revolution are but some of the developments that organisations have had to contend with in the last few years. There are, therefore, huge challenges for business leaders in the wake of constantly shifting global competition and ever-increasing change, underpinned by complexity, unpredictability, instability, and ambiguity (Nixon, 2003). In dynamic and complex environments, it is essential for organisations to continually create, validate, and apply new knowledge in the development of their products, processes, and services to ensure they add value (Bhatt, 2001). In essence, organisations seek to differentiate themselves on the basis of what they know, and managers of successful organisations are consistently searching for better ways to improve performance and results. Indeed, frequent disappointments with past management initiatives have motivated managers to gain new understanding into the underlying, but complex mechanisms, like knowledge, which govern an organisation’s effectiveness (Wiig, 1997). Knowledge is, however, not a rigid structure that excludes what does not fit—it can deal with complexity in a complex way (Davenport & Prusak, 2000). A variety of approaches to knowledge management (KM) exist, many relying heavily on technology. However, the focus of KM has moved from an early emphasis on technologies and databases to a keen appreciation of how deeply corporate knowledge is embedded in people’s experience. Organisations have learned that technology is the easy part of supporting knowledge creation; the difficult aspect is working with people to improve collaboration and knowledge sharing (Allee, 2000). To sustain long-term competitive advantage, an organisation needs to ensure a fit between its technological and social systems. In effect, technologies can be used to increase the efficiency of the people and enhance the information flow within the organisation, while social systems facilitate better communications and understanding of complex issues by bringing multiple viewpoints to a variety of situations (Bhatt, 2001). This socio-technical view of KM has spawned a number of initiatives in recent years embracing organisational, cultural, and individual issues (Pemberton & Stonehouse, 2000). One in particular, the notion of a community of practice (CoP), has played, and continues to play, a significant role in knowledge exchange and creation. Indeed, CoPs are KM’s mechanism of choice and are a valuable means of unlocking this hidden treasure (McDermott, 2000). In this sense, CoPs have an important role in the management of complexity within organisations; this is the focus of this particular article.


2015 ◽  
Vol 27 (4) ◽  
pp. 356-369 ◽  
Author(s):  
Moslem Sharifinia

Abstract A comprehensive review of macroinvertebrate studies conducted along the Iranian running waters over the last 15 years has been made by providing the most updated checklist of the Iranian running waters benthic invertebrates. Running waters ecosystems are complex environments known for their importance in terms of biodiversity. As part of the analysis, we endeavored to provide the critical re-identification of the reported species by through comparisons with the database of the Animal Diversity Web (ADW) and appropriate literature sources or expert knowledge. A total of 126 species belonging to 4 phyla have been compiled from 57 references. The phylum Arthropoda was found to comprise the most taxa (n = 104) followed by Mollusca, Annelida and Platyhelminthes. Ongoing efforts in the Iranian running waters regarding biomonitoring indices development, testing, refinement and validation are yet to be employed in streams and rivers. Overall, we suggest that future macroinvertebrate studies in Iranian running waters should be focused on long-term changes by broadening target species and strong efforts to publish data in peer-reviewed journals in English.


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