4,973 research outputs found
Design, Control, and Evaluation of a Human-Inspired Robotic Eye
Schulz S. Design, Control, and Evaluation of a Human-Inspired Robotic Eye. Bielefeld: Universität Bielefeld; 2020.The field of human-robot interaction deals with robotic systems that involve
humans and robots closely interacting with each other. With these systems
getting more complex, users can be easily overburdened by the operation
and can fail to infer the internal state of the system or its ”intentions”. A
social robot, replicating the human eye region with its familiar features and
movement patterns, that are the result of years of evolution, can counter
this. However, the replication of these patterns requires hard- and software
that is able to compete with the human characteristics and performance.
Comparing previous systems found in literature with the human capabili-
ties reveal a mismatch in this regard. Even though individual systems solve
single aspects, the successful combination into a complete system remains
an open challenge. In contrast to previous work, this thesis targets to close
this gap by viewing the system as a whole — optimizing the hard- and
software, while focusing on the replication of the human model right from
the beginning. This work ultimately provides a set of interlocking building
blocks that, taken together, form a complete end-to-end solution for the de-
sign, control, and evaluation of a human-inspired robotic eye. Based on the
study of the human eye, the key driving factors are identified as the success-
ful combination of aesthetic appeal, sensory capabilities, performance, and
functionality. Two hardware prototypes, each based on a different actua-
tion scheme, have been developed in this context. Furthermore, both hard-
ware prototypes are evaluated against each other, a previous prototype, and
the human by comparing objective numbers obtained by real-world mea-
surements of the real hardware. In addition, a human-inspired and model-
driven control framework is developed out, again, following the predefined
criteria and requirements. The quality and human-likeness of the motion,
generated by this model, is evaluated by means of a user study. This frame-
work not only allows the replication of human-like motion on the specific
eye prototype presented in this thesis, but also promotes the porting and
adaption to less equipped humanoid robotic heads. Unlike previous systems
found in literature, the presented approach provides a scaling and limiting
function that allows intuitive adjustments of the control model, which can
be used to reduce the requirements set on the target platform. Even though
a reduction of the overall velocities and accelerations will result in a slower
motion execution, the human characteristics and the overall composition of
the interlocked motion patterns remain unchanged
Referendums in the EU's constitution building process
In ten member states of the European Union (EU) the new constitutional treaty was supposed to be ratified by referendum. A growing number of theoretical models predicts that such additional ratification hurdles result in an advantage for negotiators in the bargaining game. The impact such a referendum constraint can exert, however, depends on the timing of its announcement, the remaining ratification rules as well as the preference constellations. If parliament and voters are actually in favor of the new treaty, ratification constraints may cease to affect the bargaining outcome. After presenting the theoretical foundation of these arguments, we present empirical evidence much in line with the theoretical implications. More specifically, especially for the issues changed during the intergovernmental conference, those governments gained that had scheduled a referendum and voters had a stronger preference for the status qu
Investigation On The Influence Of Remanufacturing On Production Planning And Control – A Systematic Literature Review
Production planning and control (PPC) is one of the focal operational tasks of a company, and it is used to design logistics services in a target-orientated manner so that individual customer requirements can be fulfilled. However, existing PPC framework models are still based on the prevailing linear economic procedure (take - make - dispose). Due to customers' increasing interest in sustainability and growing regulatory pressure, the Circular Economy (CE) meets these changing conditions by closing material cycles, improving resource efficiency and extending product life cycles. However, for a company to guarantee a high logistics performance, the operational PPC must be adapted to this new economic model. To this end, it needs to be investigated whether and how the adaptation of circular strategies influences existing PPC processes.
This paper focuses on the circular strategy of remanufacturing and its influence on different PPC-main tasks. The latter will be examined using a systematic literature review. Finally, the results of this analysis are compared with the Hanoverian Supply Chain Model as a PPC framework model. This comparison shows which PPC tasks are affected and which existing approaches have already been developed. Ultimately, these results provide the basis for developing a framework model for operational PPC regarding the CE
Regularity and trend to equilibrium for a non-local advection-diffusion model of active particles
We establish regularity and, under suitable assumptions, convergence to
stationary states for weak solutions of a parabolic equation with a non-linear
non-local drift term; this equation was derived from a model of active Brownian
particles with repulsive interactions in a previous work, which incorporates
advection-diffusion processes both in particle position and orientation. We
apply De Giorgi's method and differentiate the equation with respect to the
time variable iteratively to show that weak solutions become smooth away from
the initial time. This strategy requires that we obtain improved integrability
estimates in order to cater for the presence of the non-local drift. The
instantaneous smoothing effect observed for weak solutions is shown to also
hold for very weak solutions arising from distributional initial data; the
proof of this result relies on a uniqueness theorem in the style of M.~Pierre
for low-regularity solutions. The convergence to stationary states is proved
under a smallness assumption on the drift term.Comment: 37 page
Resonances in ultracold dipolar atomic and molecular gases
A previously developed approach for the numerical treatment of two particles that are confined in a finite optical-lattice potential and interact via an arbitrary isotropic interaction potential has been extended to incorporate an additional anisotropic dipole–dipole interaction (DDI). The interplay of a model but realistic short-range Born–Oppenheimer potential and the DDI for two confined particles is investigated. A variation of the strength of the DDI leads to diverse resonance phenomena. In a harmonic confinement potential some resonances show similarities to s-wave scattering resonances while in an anharmonic trapping potential like the one of an optical lattice additional inelastic confinement-induced dipolar resonances occur. The latter are due to a coupling of the relative and center-of-mass motion caused by the anharmonicity of the external confinement.Peer Reviewe
Spectral averaging techniques for Jacobi matrices
Spectral averaging techniques for one-dimensional discrete Schroedinger
operators are revisited and extended. In particular, simultaneous averaging
over several parameters is discussed. Special focus is put on proving lower
bounds on the density of the averaged spectral measures. These Wegner type
estimates are used to analyze stability properties for the spectral types of
Jacobi matrices under local perturbations
PEN as self-vetoing structural Material
Polyethylene Naphtalate (PEN) is a mechanically very favorable polymer.
Earlier it was found that thin foils made from PEN can have very high
radio-purity compared to other commercially available foils. In fact, PEN is
already in use for low background signal transmission applications (cables).
Recently it has been realized that PEN also has favorable scintillating
properties. In combination, this makes PEN a very promising candidate as a
self-vetoing structural material in low background experiments. Components
instrumented with light detectors could be built from PEN. This includes
detector holders, detector containments, signal transmission links, etc. The
current R\&D towards qualification of PEN as a self-vetoing low background
structural material is be presented.Comment: 4 pages, 7 figures, contribution to Proceedings of the sixth workshop
on Low Radioactivity Techniques 2017, 23-27 May 2017 Seoul, to be published
at AIP, editor: D. Leonar
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