121 research outputs found
NONLINEAR ADAPTIVE HEADING CONTROL FOR AN UNDERACTUATED SURFACE VESSEL WITH CONSTRAINED INPUT AND SIDESLIP ANGLE COMPENSATION
In this paper, a nonlinear adaptive heading controller is developed for an underactuated surface vessel with constrained input and sideslip angle compensation. The controller design is accomplished in a framework of backstepping technique. First, to amend the irrationality of the traditional definition of the desired heading, the desired heading is compensated by the sideslip angle. Considering the actuator physical constrain, a hyperbolic tangent function and a Nussbaum function are introduced to handle the nonlinear part of control input. The error and the disturbance are estimated and compensated by an adaptive control law. In addition, to avoid the complicated calculation of time derivatives of the virtual control, the command filter is introduced to integrate with the control law. It is analysed by the Lyapunov theory that the closed loop system is guaranteed to be uniformly ultimately bounded stability. Finally, the simulation studies illustrate the effectiveness of the proposed control method
High performance position-sensitive-detector based on graphene-silicon heterojunction
Position-sensitive-detectors (PSDs) based on lateral photoeffect have been
widely used in diverse applications, including optical engineering, aerospace
and military fields. With increasing demands in long working distance, low
energy consumption, and weak signal sensing systems, the poor responsivity of
conventional Silicon-based PSDs has become a bottleneck limiting their
applications. Herein, we propose a high-performance passive PSD based on
graphene-Si heterostructure. The graphene is adapted as a photon absorbing and
charge separation layer working together with Si as a junction, while the high
mobility provides promising ultra-long carrier diffusion length and facilitates
large active area of the device. A PSD with working area of 8 mm x 8 mm is
demonstrated to present excellent position sensitivity to weak light at nWs
level (much better than the limit of ~{\mu}Ws of Si p-i-n PSDs). More
importantly, it shows very fast response and low degree of non-linearity of
~3%, and extends the operating wavelength to the near infrared (IR) region
(1319 and 1550 nm). This work therefore provides a new strategy for high
performance and broadband PSDs.Comment: 25 pages, 13 figures, to appear in Optic
Synergistic enhancement of cancer therapy using a combination of docetaxel and photothermal ablation induced by single-walled carbon nanotubes
Lei Wang1, Mingyue Zhang1, Nan Zhang1, Jinjin Shi1, Hongling Zhang1, Min Li1, Chao Lu2, Zhenzhong Zhang1 1School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, People’s Republic of China; 2University of Maryland, College Park, MD, USA Background: Single-walled carbon nanotubes (SWNT) are poorly soluble in water, so their applications are limited. Therefore, aqueous solutions of SWNT, designed by noncovalent functionalization and without toxicity, are required for biomedical applications. Methods: In this study, we conjugated docetaxel with SWNT via p-p accumulation and used a surfactant to functionalize SWNT noncovalently. The SWNT were then conjugated with docetaxel (DTX-SWNT) and linked with NGR (Asn-Gly-Arg) peptide, which targets tumor angiogenesis, to obtain a water-soluble and tumor-targeting SWNT-NGR-DTX drug delivery system. Results: SWNT-NGR-DTX showed higher efficacy than docetaxel in suppressing tumor growth in a cultured PC3 cell line in vitro and in a murine S180 cancer model. Tumor volumes in the S180 mouse model decreased considerably under near-infrared radiation compared with the control group. Conclusion: The SWNT-NGR-DTX drug delivery system may be promising for high treatment efficacy with minimal side effects in future cancer therapy. Keywords: single-walled carbon nanotubes, docetaxel, NGR peptide, tumor-targeting, near-infrared radiatio
Strategies for Searching Video Content with Text Queries or Video Examples
The large number of user-generated videos uploaded on to the Internet
everyday has led to many commercial video search engines, which mainly rely on
text metadata for search. However, metadata is often lacking for user-generated
videos, thus these videos are unsearchable by current search engines.
Therefore, content-based video retrieval (CBVR) tackles this metadata-scarcity
problem by directly analyzing the visual and audio streams of each video. CBVR
encompasses multiple research topics, including low-level feature design,
feature fusion, semantic detector training and video search/reranking. We
present novel strategies in these topics to enhance CBVR in both accuracy and
speed under different query inputs, including pure textual queries and query by
video examples. Our proposed strategies have been incorporated into our
submission for the TRECVID 2014 Multimedia Event Detection evaluation, where
our system outperformed other submissions in both text queries and video
example queries, thus demonstrating the effectiveness of our proposed
approaches
Effective Quantization for Diffusion Models on CPUs
Diffusion models have gained popularity for generating images from textual
descriptions. Nonetheless, the substantial need for computational resources
continues to present a noteworthy challenge, contributing to time-consuming
processes. Quantization, a technique employed to compress deep learning models
for enhanced efficiency, presents challenges when applied to diffusion models.
These models are notably more sensitive to quantization compared to other model
types, potentially resulting in a degradation of image quality. In this paper,
we introduce a novel approach to quantize the diffusion models by leveraging
both quantization-aware training and distillation. Our results show the
quantized models can maintain the high image quality while demonstrating the
inference efficiency on CPUs. The code is publicly available at:
https://github.com/intel/intel-extension-for-transformers
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