210 research outputs found
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MZnet : mail service for personal micro-computer systems
Traditional computer mail systems involve a co-resident User Agent (UA) and Mail Transfer System (MTS) on a time-shared host computer which may be connected to other hosts ina network, with new mail posted or delivered directly through co-resident mail-slot programs. To introduce personal micro-computers (PCs) into this environment requires modification of the traditional mail system architecture. To this end, the MZnet project uses a split-slot model, placing UA programs on the PCs while leaving MTA programs on a mail relay host which can provide authentication and buffering. The split-slot arrangement might be viewed as a new protocol level which operates somewhere between the currently defined MTS-MTS and UA-UA levels
3D Object Discovery and Modeling Using Single RGB-D Images Containing Multiple Object Instances
Unsupervised object modeling is important in robotics, especially for
handling a large set of objects. We present a method for unsupervised 3D object
discovery, reconstruction, and localization that exploits multiple instances of
an identical object contained in a single RGB-D image. The proposed method does
not rely on segmentation, scene knowledge, or user input, and thus is easily
scalable. Our method aims to find recurrent patterns in a single RGB-D image by
utilizing appearance and geometry of the salient regions. We extract keypoints
and match them in pairs based on their descriptors. We then generate triplets
of the keypoints matching with each other using several geometric criteria to
minimize false matches. The relative poses of the matched triplets are computed
and clustered to discover sets of triplet pairs with similar relative poses.
Triplets belonging to the same set are likely to belong to the same object and
are used to construct an initial object model. Detection of remaining instances
with the initial object model using RANSAC allows to further expand and refine
the model. The automatically generated object models are both compact and
descriptive. We show quantitative and qualitative results on RGB-D images with
various objects including some from the Amazon Picking Challenge. We also
demonstrate the use of our method in an object picking scenario with a robotic
arm
Motion Priority Optimization Framework towards Automated and Teleoperated Robot Cooperation in Industrial Recovery Scenarios
In this study, we present an optimization framework for efficient motion
priority design between automated and teleoperated robots in an industrial
recovery scenario. Although robots have recently become increasingly common in
industrial sites, there are still challenges in achieving human-robot
collaboration/cooperation (HRC), where human workers and robots are engaged in
collaborative and cooperative tasks in a shared workspace. For example, the
corresponding factory cell must be suspended for safety when an industrial
robot drops an assembling part in the workspace. After that, a human worker is
allowed to enter the robot workspace to address the robot recovery. This
process causes non-continuous manufacturing, which leads to a productivity
reduction. Recently, robotic teleoperation technology has emerged as a
promising solution to enable people to perform tasks remotely and safely. This
technology can be used in the recovery process in manufacturing failure
scenarios. Our proposition involves the design of an appropriate priority
function that aids in collision avoidance between the manufacturing and
recovery robots and facilitates continuous processes with minimal production
loss within an acceptable risk level. This paper presents a framework,
including an HRC simulator and an optimization formulation, for finding optimal
parameters of the priority function. Through quantitative and qualitative
experiments, we address the proof of our novel concept and demonstrate its
feasibility
Transfer of Fas (CD95) protein from the cell surface to the surface of polystyrene beads coated with anti-Fas antibody clone CH-11
Mouse monoclonal anti-Fas (CD95) antibody clone CH-11 has been widely used in research on apoptosis. CH-11 has the ability to bind to Fas protein on cell surface and induce apoptosis. Here, we used polystyrene beads coated with CH-11 to investigate the role of lipid rafts in Fas-mediated apoptosis in SKW6.4 cells. Unexpectedly, by treatment of the cells with CH-11-coated beads Fas protein was detached from cell surface and transferred to the surface of CH-11-coated beads. Western blot analysis showed that Fas protein containing both extracellular and intracellular domains was attached to the beads. Fas protein was not transferred from the cells to the surface of the beads coated with other anti-Fas antibodies or Fas ligand. Similar phenomenon was observed in Jurkat T cells. Furthermore, CH-11-induced apoptosis was suppressed by pretreatment with CH-11-coated beads in Jurkat cells. These results suggest that CH-11 might possess distinct properties on Fas protein compared with other anti-Fas antibodies or Fas ligand, and also suggest that caution should be needed to use polystyrene beads coated with antibodies such as CH-11
Learning to Dexterously Pick or Separate Tangled-Prone Objects for Industrial Bin Picking
Industrial bin picking for tangled-prone objects requires the robot to either
pick up untangled objects or perform separation manipulation when the bin
contains no isolated objects. The robot must be able to flexibly perform
appropriate actions based on the current observation. It is challenging due to
high occlusion in the clutter, elusive entanglement phenomena, and the need for
skilled manipulation planning. In this paper, we propose an autonomous,
effective and general approach for picking up tangled-prone objects for
industrial bin picking. First, we learn PickNet - a network that maps the
visual observation to pixel-wise possibilities of picking isolated objects or
separating tangled objects and infers the corresponding grasp. Then, we propose
two effective separation strategies: Dropping the entangled objects into a
buffer bin to reduce the degree of entanglement; Pulling to separate the
entangled objects in the buffer bin planned by PullNet - a network that
predicts position and direction for pulling from visual input. To efficiently
collect data for training PickNet and PullNet, we embrace the self-supervised
learning paradigm using an algorithmic supervisor in a physics simulator.
Real-world experiments show that our policy can dexterously pick up
tangled-prone objects with success rates of 90%. We further demonstrate the
generalization of our policy by picking a set of unseen objects. Supplementary
material, code, and videos can be found at https://xinyiz0931.github.io/tangle.Comment: 8 page
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