785 research outputs found
Electrolysis-based Parylene Balloon Actuators for Movable Neural Probes
In order to track a specific neuron and keep good sampling neural signals during chronic implantation, the neural probes are highly desired to have moving capability. This paper presents a novel electrolysis-based parylene balloon actuator fabricated with MEMS technology. The actuator is integrated with silicon probe to make it movable. A new fabrication technology has been developed to build a parylene balloon structure with silicon spring structure, electrolysis electrodes and electrolyte inside. By applying little current to electrolysis electrodes, high pressure is generated inside the parylene balloon by electrolysis. The spring structure is stretched with the parylene balloon expansion. Therefore the neural probe is moved by the actuation. The electrolysis actuator can generate large stain and pressure, requires modest electrical power and produces minimal heat. Due to the large volume expansion obtained via electrolysis, the small actuator can create a large force. The new electrolysis actuators for movable neural probes have been fabricated and validated
Electrolysis-based diaphragm actuators
This work presents a new electrolysis-based microelectromechanical systems (MEMS) diaphragm actuator. Electrolysis is a technique for converting electrical energy to pneumatic energy. Theoretically electrolysis can achieve a strain of 136 000% and is capable of generating a pressure above 200 MPa. Electrolysis actuators require modest electrical power and produce minimal heat. Due to the large volume expansion obtained via electrolysis, small actuators can create a large force. Up to 100 µm of movement was achieved by a 3 mm diaphragm. The actuator operates at room temperature and has a latching and reversing capability
Integrated parylene-cabled silicon probes for neural prosthetics
Recent advances in the field of neural prosthetics have demonstrated the thought control of a computer cursor. This capability relies primarily on electrode array surgically implanted into the brain as an acquisition source of neural activity. Various technologies have been developed for signal extraction; however most suffer from either fragile electrode shanks and bulky cables or inefficient use of surgical site areas. Here we present a design and initial testing results from high electrode density, silicon based arrays system with an integrated parylene cable. The greatly reduced flexible rigidity of the parylene cable is believed to relief possible mechanical damages due to relative motion between a brain and its skull
DORT: Modeling Dynamic Objects in Recurrent for Multi-Camera 3D Object Detection and Tracking
Recent multi-camera 3D object detectors usually leverage temporal information
to construct multi-view stereo that alleviates the ill-posed depth estimation.
However, they typically assume all the objects are static and directly
aggregate features across frames. This work begins with a theoretical and
empirical analysis to reveal that ignoring the motion of moving objects can
result in serious localization bias. Therefore, we propose to model Dynamic
Objects in RecurrenT (DORT) to tackle this problem. In contrast to previous
global Bird-Eye-View (BEV) methods, DORT extracts object-wise local volumes for
motion estimation that also alleviates the heavy computational burden. By
iteratively refining the estimated object motion and location, the preceding
features can be precisely aggregated to the current frame to mitigate the
aforementioned adverse effects. The simple framework has two significant
appealing properties. It is flexible and practical that can be plugged into
most camera-based 3D object detectors. As there are predictions of object
motion in the loop, it can easily track objects across frames according to
their nearest center distances. Without bells and whistles, DORT outperforms
all the previous methods on the nuScenes detection and tracking benchmarks with
62.5\% NDS and 57.6\% AMOTA, respectively. The source code will be released
Accurate Single Stage Detector Using Recurrent Rolling Convolution
Most of the recent successful methods in accurate object detection and
localization used some variants of R-CNN style two stage Convolutional Neural
Networks (CNN) where plausible regions were proposed in the first stage then
followed by a second stage for decision refinement. Despite the simplicity of
training and the efficiency in deployment, the single stage detection methods
have not been as competitive when evaluated in benchmarks consider mAP for high
IoU thresholds. In this paper, we proposed a novel single stage end-to-end
trainable object detection network to overcome this limitation. We achieved
this by introducing Recurrent Rolling Convolution (RRC) architecture over
multi-scale feature maps to construct object classifiers and bounding box
regressors which are "deep in context". We evaluated our method in the
challenging KITTI dataset which measures methods under IoU threshold of 0.7. We
showed that with RRC, a single reduced VGG-16 based model already significantly
outperformed all the previously published results. At the time this paper was
written our models ranked the first in KITTI car detection (the hard level),
the first in cyclist detection and the second in pedestrian detection. These
results were not reached by the previous single stage methods. The code is
publicly available.Comment: CVPR 201
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Ion liquid chromatography on-a-chip with beads-packed parylene column
A parylene-MEMS ion-exchange Liquid Chromatography (LC) chip is presented here. The chip is integrated with microfluidic I/O ports, a separation column, frits/filters, and a conductivity detector. The column is packed with conventional LC stationary phase support materials, i.e. micro-beads with surface functional groups. To withstand high pressure normally encountered in high performance liquid chromatography (HPLC), a self-aligned, channel-anchoring technique is developed to increase the pressure rating of the parylene microfluidic devices from 30 to at least 800psi. On-chip injection, separation and detection of anions in water, with ~25 ppm concentration, have been successfully demonstrated. To our knowledge, this is the first demonstration of microbeads-packed column ion liquid Chromatography (LC) on a chip
PointLLM: Empowering Large Language Models to Understand Point Clouds
The unprecedented advancements in Large Language Models (LLMs) have created a
profound impact on natural language processing but are yet to fully embrace the
realm of 3D understanding. This paper introduces PointLLM, a preliminary effort
to fill this gap, thereby enabling LLMs to understand point clouds and offering
a new avenue beyond 2D visual data. PointLLM processes colored object point
clouds with human instructions and generates contextually appropriate
responses, illustrating its grasp of point clouds and common sense.
Specifically, it leverages a point cloud encoder with a powerful LLM to
effectively fuse geometric, appearance, and linguistic information. We collect
a novel dataset comprising 660K simple and 70K complex point-text instruction
pairs to enable a two-stage training strategy: initially aligning latent spaces
and subsequently instruction-tuning the unified model. To rigorously evaluate
our model's perceptual abilities and its generalization capabilities, we
establish two benchmarks: Generative 3D Object Classification and 3D Object
Captioning, assessed through three different methods, including human
evaluation, GPT-4/ChatGPT evaluation, and traditional metrics. Experiment
results show that PointLLM demonstrates superior performance over existing 2D
baselines. Remarkably, in human-evaluated object captioning tasks, PointLLM
outperforms human annotators in over 50% of the samples. Codes, datasets, and
benchmarks are available at https://github.com/OpenRobotLab/PointLLM .Comment: 19 pages. Empowering large language models with 3D point cloud
understanding, accompanied by a novel dataset and carefully designed
benchmarks. Project page: https://runsenxu.com/projects/PointLL
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