MUCKE aims to mine a large volume of images, to structure them conceptually and to use this conceptual structuring in order to improve large-scale image retrieval. The last decade witnessed important progress concerning low-level image representations. However, there are a number problems which need to be solved in order to unleash the full potential of image mining in applications. The central problem with low-level representations is the mismatch between them and the human interpretation of image content. This problem can be instantiated, for instance, by the incapability of existing descriptors to capture spatial relationships between the concepts represented or by their incapability to convey an explanation of why two images are similar in a content-based image retrieval framework. We start by assessing existing local descriptors for image classification and by proposing to use co-occurrence matrices to better capture spatial relationships in images. The main focus in MUCKE is on cleaning large scale Web image corpora and on proposing image representations which are closer to the human interpretation of images. Consequently, we introduce methods which tackle these two problems and compare results to state of the art methods. Note: some aspects of this deliverable are withheld at this time as they are pending review. Please contact the authors for a preview.

http://ieeexplore.ieee.org/iel2/4524/12820/00592460.pdf

Image Processing

Individual-based modeling is a new, exciting discipline that allows ecologists to explore, using computer simulations, how properties of populations and ecosystems might evolve from the characteristics and behaviors of individual organisms. Individual-based Modeling and Ecology, written by Volker Grimm and Steven F. Railsback, gives an excellent introduction and overview of this field. It should be read by everyone interested in individual-based modeling, and especially by anyone contemplating developing, or being involved with a group developing, an individualbased model.

http://www.gbv.de/dms/weimar/toc/396272002_toc.pdf

Individual-based modeling and ecology

This self-contained introduction to the distributed control of robotic networks offers a distinctive blend of computer science and control theory. The book presents a broad set of tools for understanding coordination algorithms, determining their correctness, and assessing their complexity; and it analyzes various cooperative strategies for tasks such as consensus, rendezvous, connectivity maintenance, deployment, and boundary estimation. The unifying theme is a formal model for robotic networks that explicitly incorporates their communication, sensing, control, and processing capabilities--a model that in turn leads to a common formal language to describe and analyze coordination algorithms.Written for first- and second-year graduate students in control and robotics, the book will also be useful to researchers in control theory, robotics, distributed algorithms, and automata theory. The book provides explanations of the basic concepts and main results, as well as numerous examples and exercises.Self-contained exposition of graph-theoretic concepts, distributed algorithms, and complexity measures for processor networks with fixed interconnection topology and for robotic networks with position-dependent interconnection topology Detailed treatment of averaging and consensus algorithms interpreted as linear iterations on synchronous networks Introduction of geometric notions such as partitions, proximity graphs, and multicenter functions Detailed treatment of motion coordination algorithms for deployment, rendezvous, connectivity maintenance, and boundary estimation

/pdf/distributed-control-of-robotic-networks-a-mathematical-1q6nfcvi2l.pdf

Distributed Control of Robotic Networks: A Mathematical Approach to Motion Coordination Algorithms

1. What are Allee effects? 2. Mechanisms for Allee effects 3. Population dynamics: modelling demographic Allee effects 4. Genetics and evolution 5. Conservation and management 6. Conclusions and perspectives

Allee Effects in Ecology and Conservation

Synchronization in complex networks of phase oscillators: A survey

This article describes PCOD, a cooperative control framework for stabilizing relative equilibria in a model of self-propelled, steered particles moving in the plane at unit speed. Relative equilibria correspond either to motion of all of the particles in the same direction or to motion of all of the particles around the same circle. Although the framework applies to time-varying and directed interaction between individuals, we focus here on time-invariant and undirected interaction, using the Laplacian matrix of the interaction graph to design a set of decentralized control laws applicable to mobile sensor networks. Since the direction of motion of each particle is represented in the framework by a point on the unit circle, the closed-loop model has coupled-phase oscillator dynamics.

Oscillator Models and Collective Motion

Polarity, group velocity, and inter-individual spacing are characteristics of fish schools that strongly affect individual school members. However, these characteristics are group-level 'emergent properties': collective outcomes of behavioral interactions among members, not under direct control of any single member. The relationships between members' behaviors and the emergent group properties they produce are complex and poorly understood. In this study, we quantified 3D trajectories of all individual fish within 4- and 8-fish populations of Danio aequipinnatus, using stereo videography and a computerized tracking algorithm. We compared group polarity, group speed, and mean nearest-neighbor distances of schools within these populations to a simulation model that explored how fish responded to attraction/repulsion, alignment and random forces. Real fish exhibited a high degree of temporal variability in both polarity and group speed. Polarity and speed of simulated schools depended very strongly on the strength of the alignment force. Time-averaged polarity of real fish schools was most similar to simulated schools when alignment force was 1 to 5 % of the attraction/repulsion force. For both real and simulated fish, a clear relationship existed between group speed and polarity: polarized groups were faster than non-polarized groups. We propose a multi-dimensional state space where several emergent property statistics are represented along the axes, and suggest certain 'preferred' ranges of state space within which animal groups tend to localize, and in which they can sustain distinct types of regular architecture.

/pdf/individual-behavior-and-emergent-properties-of-fish-schools-2z5optvhuo.pdf

Individual behavior and emergent properties of fish schools: a comparison of observation and theory

SUMMARY Reduction in global ocean pH due to the uptake of increased atmospheric CO 2 is expected to negatively affect calcifying organisms, including the planktonic larval stages of many marine invertebrates. Planktonic larvae play crucial roles in the benthic–pelagic life cycle of marine organisms by connecting and sustaining existing populations and colonizing new habitats. Calcified larvae are typically denser than seawater and rely on swimming to navigate vertically structured water columns. Larval sand dollars Dendraster excentricus have calcified skeletal rods supporting their bodies, and propel themselves with ciliated bands looped around projections called arms. Ciliated bands are also used in food capture, and filtration rate is correlated with band length. As a result, swimming and feeding performance are highly sensitive to morphological changes. When reared at an elevated P CO2 level (1000 ppm), larval sand dollars developed significantly narrower bodies at fourand six-arm stages. Morphological changes also varied between four observed maternal lineages, suggesting within-population variation in sensitivity to changes in P CO2 level. Despite these morphological changes, P CO2 concentration alone had no significant effect on swimming speeds. However, acidified larvae had significantly smaller larval stomachs and bodies, suggesting reduced feeding performance. Adjustments to larval morphologies in response to ocean acidification may prioritize swimming over feeding, implying that negative consequences of ocean acidification are carried over to later developmental stages.

/pdf/effects-of-ocean-acidification-induced-morphological-changes-4t9ly5zv4w.pdf

Effects of ocean-acidification-induced morphological changes on larval swimming and feeding

Resource distributions in the ocean are heterogeneous in time and space. Theory predicts planktonic predators may exploit these resource patches by modifying their movements in response to mechanical or chemical stimuli. In the laboratory, we used the protistan predator Oxyrrhis marina to simultaneously quantify changes in predator population distributions on scales of centimeters and hours and predators' individual three-dimensional swimming behaviors on scales of micrometers and seconds. Movements of O. marina in a 0.3-m column were monitored for several hours before and after introducing a 5-mm layer of either Isochrysis galbana prey cells or cell-free I. galbana filtrate. Within both types of layers, significant increases in turning rates and decreases in vertical velocities were observed. O. marina swimming speed increased significantly in response to intact I. galbana cells, but not in response to I. galbana exudates. Changes in predators' microscopic movements were concurrent with rapid (minutes) and sustained (hours) increases in relative predator abundance within layers. After 4 h, predator abundance inside the thin layers was up to 20 times higher than before introduction of prey. Estimates of realized growth rates for predator populations with aggregate behaviors were an order of magnitude faster than estimates for hypothetical, nonaggregating predators. The observed foraging behaviors of O. marina, and by implication other planktonic predators, increase effective prey availability to the predators. Modulation of individual-level behaviors can result in significant changes in community-level characteristics, including population distributions, growth, and ingestion rates.

Individual foraging behaviors and population distributions of a planktonic predator aggregating to phytoplankton thin layers

Many Antarctic seabirds depend on prey that are patchy, cryptic, ephemeral, and unpredictable in location. These predators typically employ two alternative behavioral strategies for locating resource patches: direct visual or olfactory detection, and indirect detection (local enhancement) by sighting other predators that are already exploiting a patch. We developed a model of direct detection and local enhancement in seabirds that predicts how foraging success varies with behavioral strategy, seabird densities, and prey swarm density and detectability. Application of the model to Black-browed Albatrosses foraging for Antarctic krill near South Georgia suggests that local enhancement is generally a highly effective foraging strategy, and that the fraction of time albatrosses spend in feeding flocks should show strong interactions between prey and conspecific densities. To test these predictions, we analyzed survey data collected near South Georgia in January-March 1986. Our analysis suggests a strong Allee-type density dependence in foraging success that was qualitatively and quantitatively consistent with model predictions. This density dependence suggests a potential for destabilizing patterns of resource utilization and reproductive suc- cess in Black-browed Albatrosses that may have important implications for conservation of albatrosses and other Antarctic species.

Daniel Grünbaum

Papers

Oscillator Models and Collective Motion

Individual behavior and emergent properties of fish schools: a comparison of observation and theory

Effects of ocean-acidification-induced morphological changes on larval swimming and feeding

Individual foraging behaviors and population distributions of a planktonic predator aggregating to phytoplankton thin layers

Black-browed albatrosses foraging on antarctic krill: density-dependence through local enhancement?