Systema naturae（自然の体系）

Robotic Development Environments (RDEs) have come to play an increasingly important role in robotics research in general, and for the development of architectures for mobile robots in particular. Yet, no systematic evaluation of available RDEs has been performed; establishing a comprehensive list of evaluation criteria targeted at robotics applications is desirable that can subsequently be used to compare their strengths and weaknesses. Moreover, there are no practical evaluations of the usability and impact of a large selection of RDEs that provides researchers with the information necessary to select an RDE most suited to their needs, nor identifies trends in RDE research that suggest directions for future RDE development.

This survey addresses the above by selecting and describing nine open source, freely available RDEs for mobile robots, evaluating and comparing them from various points of view. First, based on previous work concerning agent systems, a conceptual framework of four broad categories is established, encompassing the characteristics and capabilities that an RDE supports. Then, a practical evaluation of RDE usability in designing, implementing, and executing robot architectures is presented. Finally, the impact of specific RDEs on the field of robotics is addressed by providing a list of published applications and research projects that give concrete examples of areas in which systems have been used. The comprehensive evaluation and comparison of the nine RDEs concludes with suggestions of how to use the results of this survey and a brief discussion of future trends in RDE design.

https://hrilab.tufts.edu/publications/rdesurvey.pdf

Development environments for autonomous mobile robots: A survey

Batch reinforcement learning methods provide a powerful framework for learning efficiently and effectively in autonomous robots. The paper reviews some recent work of the authors aiming at the successful application of reinforcement learning in a challenging and complex domain. It discusses several variants of the general batch learning framework, particularly tailored to the use of multilayer perceptrons to approximate value functions over continuous state spaces. The batch learning framework is successfully used to learn crucial skills in our soccer-playing robots participating in the RoboCup competitions. This is demonstrated on three different case studies.

/pdf/reinforcement-learning-for-robot-soccer-xc27gxtqaw.pdf

Reinforcement learning for robot soccer

https://science.sciencemag.org/content/sci/49/1263/265.3.full.pdf

British Antarctic "Terra Nova" Expedition, 1910

More than 4500 species belong to the crustacean sub-order Gammaridea (order Amphipoda) (Bousfield Among Amphipods, the Gammaridea are the most widespread group and are found throughout a range of marine, freshwater, and terrestrial habitats (Bousfield Lincoln, whereas the three other amphipod sub-orders (Hyperiidea, Ingolfiellidea, and Caprellidea) are highly specialized and ecologically restricted. Gammarus is the amphipod genus with the highest number of epigean freshwater species, comprising over 100 species that are distributed throughout the Northern Hemisphere (Karaman and Pinkster Abiotic factors such as temperature, salinity, oxygen, acidity, and pollution play an important role in the distribution of Gammarus species (Whitehurst and Lindsey and members of this species are often found in great abundance under rocks, in gravel, or in coarse substrates and among living and dead vegetation (Fitter and Manuel). These substrata provide both shelter from predators and a supply of organic detritus and other foodstuffs, with the result that in many riverine communities, amphipod species such as Gammarus pulex (Linnaeus) may represent the dominant macroinvertebrate in terms of biomass (Macneil et al. Shaw.

Gammarus spp. in aquatic ecotoxicology and water quality assessment: toward integrated multilevel tests.

Here we present a set of methods for documenting (exo-)morphology by applying autofluorescence imaging. For arthropods, but also for other taxa, autofluorescence imaging combined with composite imaging is a fast documentation method with high-resolution capacities. Compared to conventional micro- and macrophotography, the illumination is much more homogenous, and structures are often better contrasted. Applying different wavelengths to the same object can additionally be used to enhance distinct structures. Autofluorescence imaging can be applied to dried and embedded specimens, but also directly on specimens within their storage liquid. This has an enormous potential for the documentation of rare specimens and especially type specimens without the need of preparation. Also for various fossils, autofluorescence can be used to enhance the contrast between the fossil and the matrix significantly, making even smallest details visible. 'Life-colour' fluorescence especially is identified as a technique with great potential. It provides additional information for which otherwise more complex methods would have to be applied. The complete range of differences and variations between fluorescence macrophotography and different types of fluorescence microscopy techniques are here explored and evaluated in detail. Also future improvements are suggested. In summary, autofluorescence imaging is a powerful, easy and fast-to-apply tool for morphological studies.

Autofluorescence imaging, an excellent tool for comparative morphology.

We give an overview of available techniques for imaging and documenting applied to gammarideans and discuss their advantages and disadvantages. Although recent techniques, such as confocal laser scanning microscopy (cLSM), focused ion beam scanning electron microscopy (FIB SEM), or computed microtomography (μCT), provide new possibilities to detect and document structures, these high-tech devices are expensive, and access to them is often limited. Alternatively, there are many possibilities to enhance the capabilities of established techniques such as macrophotography and light microscopy. We discuss improvements of the illumination with polarized light and the possibilities of utilizing the autofluorescence of animals such as the gammarideans. In addition, we present software-based enhancing tools such as image fusion and image stitching.

/pdf/imaging-and-documenting-gammarideans-3gblf2c2id.pdf

Imaging and Documenting Gammarideans

Dikerogammarus villosus, a Ponto-Caspian species, is known to be a particularly successful invader, and is currently the prevailing invasive gammarid in Southern German large waters. Field observations suggest that D. villosus has replaced the native G. pulex and the invasive D. haemobaphes, also a Ponto-Caspian species, in some reaches of the German Danube. Dikerogammarus villosus is also believed to be the reason why Echinogammarus berilloni, a Mediterranean species, and Dikerogammarus bispinosus, a further Ponto-Caspian gammaridean species, could not build significant populations in Southern German rivers. Because intraguild predation (IGP) is regarded as a major force leading to species displacements, we hypothesized that superiority in predation by D. villosus is responsible for the disappearance or limited occurrence of several native and invasive gammarideans in many reaches of Southern German waters. To test this hypothesis, we conducted a series of laboratory IGP experiments with 1:1 combinations in which D. villosus was allowed to prey on other gammarids and vice versa. We also studied the extent of cannibalism within species. Dikerogammarus villosus was a stronger predator than G. pulex and E. berilloni. However, D. villosus was not stronger in predation than its relatives D. haemobaphes and D. bispinosus, although results with the combinations of D. villosus and D. bispinosus were less conclusive, especially in the female–female combination. Cannibalism rate was high in D. haemobaphes compared with other species. We conclude that superiority in IGP experiments could explain the disappearance of G. pulex and the missing or limited occurrence of E. berilloni since the arrival of D. villosus in Southern German rivers. However, the results of IGP experiments do not explain why D. haemobaphes was displaced by D. villosus in many places and why D. bispinosus could not build significant populations in Southern German waters. Possibly specific combinations between mutual predation and cannibalism or factors other than predation could have affected displacement and occurrence patterns of Dikerogammarus species in Southern German waters.

Mutual predation between and cannibalism within several freshwater gammarids: Dikerogammarus villosus versus one native and three invasives

The pontogammarid amphipod Dikerogammarus villosus, originally a Ponto-Caspian faunal element, has, in the recent 15-20 years, successfully invaded various aquatic systems in Europe including Lake Constance. In these rivers and lakes it had and still has severe ecological impact on native macro-invertebrates, often eliminating the native and earlier established gammaridean species. In order to test the hypothesis that the mode of food acquisition of D. villosus is of significance for this phenomenon, we focused on the mouthparts of D. villosus, i.e., mandibles, the two pairs of maxillae and the maxillipeds using SEM. Contrary to expectations, provoked by field and laboratory observations, the results of this study show that the mouthparts of D. villosus are not highly specialized just for carnivory and predation. Indeed, the stout mandibles, with their well-developed incisors enable to kill even prey with robust integument, but other modes of feeding are possible. On the maxillulae, maxillae, and...

https://bioone.org/journals/journal-of-crustacean-biology/volume-28/issue-1/07-2867R.1/MOUTHPARTS-OF-THE-PONTO-CASPIAN-INVADER-DIKEROGAMMARUS-VILLOSUS-AMPHIPODA/10.1651/07-2867R.1.pdf

Mouthparts of the ponto-caspian invader dikerogammarus villosus (amphipoda: pontogammaridae)

Substrate choice, swimming activity and risk to predation by burbot (Lota lota) of the well established Gammarus roeselii and the invader Dikerogammarus villosus were studied in mixed and single-species aquarium experiments. We used stones, gravel and aquatic weeds (Elodea, Chara) as substrates. We hypothesized that both species have different substrate preferences and that substrate affects the predation risk. We also assumed that presence of D. villosus influences substrate preference and predation risk of G. roeselii since the invader is known to affect the behavior of other gammarids. Adults of D. villosus in single species experiments and juveniles in mixed and single species experiments were evenly distributed over the different substrates but adults in mixed species experiments were more likely to prefer stone substrate. In contrast, adults and juveniles of G. roeselii clearly preferred aquatic weeds independent of the presence/absence of the invader. Both species preferred substrates with fissured surface over substrates with smooth surface. Gammarus roeselii was observed swimming more often than D. villosus in the open water but its swimming activity was lower when its preferred substrate was present compared with its swimming activity if non-preferred substrates were present. Predation rate of burbot on D. villosus was comparatively low and independent of the substrate. Burbot consumed many more G. roeselii than D. villosus, both in mixed and single species experiments. But when the preferred substrate of G. roeselii (weeds) was used in the experiments, predation rate of burbot on G. roeselii was somewhat lower than that when non-preferred substrates were present. The results of the experiments support our hypothesis that the gammarids studied here have different substrate preferences and that presence of the preferred substrate can affect predation risk. However, there is no evidence that presence of D. villosus affected substrate choice or predation risk in G. roeselii. We consider that differences in use of spatial niches permit co-existence of G. roeselii and D. villosus in the wild when substrates are diverse. The fact that G. roeselii than D. villosus is more often observed swimming in the open water may explain its higher risk of being captured by fish.

Gerd Mayer

Papers

Autofluorescence imaging, an excellent tool for comparative morphology.

Imaging and Documenting Gammarideans

Mutual predation between and cannibalism within several freshwater gammarids: Dikerogammarus villosus versus one native and three invasives

Mouthparts of the ponto-caspian invader dikerogammarus villosus (amphipoda: pontogammaridae)

Influence of substrate preference and complexity on co-existence of two non-native gammarideans (Crustacea: Amphipoda)