105 research outputs found
Case History on Prevention of the Landslide at Luoyiqi by Means of Rigid Frame Retaining Structure
This paper presents a new special type of retaining structure which prevents the large-scale landslide. It is named the rigid frame retaining structure. The author in this paper proposed a new computation method, i.e., analysis of the rigid frame within elastic foundation. The new formulations have been performed according to E. Ninkler\u27s theory and the difference principle and with the help of fundamental knowledge of strength of material and matrix algebra. The descriptions of the design and construction of the rigid frame retaining structure were given
TNF-α Induces Two Distinct Caspase-8 Activation Pathways
SummaryThe inflammatory response of mammalian cells to TNF-α can be switched to apoptosis either by cotreatment with a protein synthesis inhibitor, cycloheximide, or Smac mimetic, a small molecule mimic of Smac/Diablo protein. Cycloheximide promotes caspase-8 activation by eliminating endogenous caspase-8 inhibitor, c-FLIP, while Smac mimetic does so by triggering autodegradation of cIAP1 and cIAP2 (cIAP1/2), leading to the release of receptor interacting protein kinase (RIPK1) from the activated TNF receptor complex to form a caspase-8-activating complex consisting of RIPK1, FADD, and caspase-8. This process also requires the action of CYLD, a RIPK1 K63 deubiquitinating enzyme. RIPK1 is critical for caspase-8 activation-induced by Smac mimetic but dispensable for that triggered by cycloheximide. Moreover, Smac mimetic-induced caspase-8 activation is not blocked by endogenous c-FLIP. These findings revealed that TNF-α is able to induce apoptosis via two distinct caspase-8 activation pathways that are differentially regulated by cIAP1/2 and c-FLIP
Thinking Twice: Clinical-Inspired Thyroid Ultrasound Lesion Detection Based on Feature Feedback
Accurate detection of thyroid lesions is a critical aspect of computer-aided
diagnosis. However, most existing detection methods perform only one feature
extraction process and then fuse multi-scale features, which can be affected by
noise and blurred features in ultrasound images. In this study, we propose a
novel detection network based on a feature feedback mechanism inspired by
clinical diagnosis. The mechanism involves first roughly observing the overall
picture and then focusing on the details of interest. It comprises two parts: a
feedback feature selection module and a feature feedback pyramid. The feedback
feature selection module efficiently selects the features extracted in the
first phase in both space and channel dimensions to generate high semantic
prior knowledge, which is similar to coarse observation. The feature feedback
pyramid then uses this high semantic prior knowledge to enhance feature
extraction in the second phase and adaptively fuses the two features, similar
to fine observation. Additionally, since radiologists often focus on the shape
and size of lesions for diagnosis, we propose an adaptive detection head
strategy to aggregate multi-scale features. Our proposed method achieves an AP
of 70.3% and AP50 of 99.0% on the thyroid ultrasound dataset and meets the
real-time requirement. The code is available at
https://github.com/HIT-wanglingtao/Thinking-Twice.Comment: 20 pages, 11 figures, released code for
https://github.com/HIT-wanglingtao/Thinking-Twic
Multi-Objective Topology Optimization for Curved Arm of Multifunctional Billet Tong Based on Characterization of Working Conditions
A windlass driven heavy duty multifunctional billet tong was designed for large-scale forging and casting to reduce the number of auxiliary material handling devices in manufacturing workshops. To improve its mechanical performance and safety, a novel multi-objective topology optimization method for its curved arm is proposed in this paper. Firstly, the influence of different open angles and working frequencies for the curved arm was simplified to a multi-objective optimization problem. A comprehensive evaluation function was constructed using the compromise programming method, and a mathematical model of multi-objective topology optimization was established. Meanwhile, a radar chart was employed to portray the comparative measures of working conditions, the weight coefficient for each working condition was determined based on the corresponding enclosed areas, combining the stress indices, the displacement indices and the frequency indices of all working conditions. The optimization results showed that the stiffness and strength of the curved arm can be improved while its weight can be reduced by 10.77%, which shows that it is feasible and promising to achieve a lightweight design of the curved arm of a billet tong. The proposed method can be extended to other equipment with complex working conditions
Multi-Objective Topology Optimization for Curved Arm of Multifunctional Billet Tong Based on Characterization of Working Conditions
A windlass driven heavy duty multifunctional billet tong was designed for large-scale forging and casting to reduce the number of auxiliary material handling devices in manufacturing workshops. To improve its mechanical performance and safety, a novel multi-objective topology optimization method for its curved arm is proposed in this paper. Firstly, the influence of different open angles and working frequencies for the curved arm was simplified to a multi-objective optimization problem. A comprehensive evaluation function was constructed using the compromise programming method, and a mathematical model of multi-objective topology optimization was established. Meanwhile, a radar chart was employed to portray the comparative measures of working conditions, the weight coefficient for each working condition was determined based on the corresponding enclosed areas, combining the stress indices, the displacement indices and the frequency indices of all working conditions. The optimization results showed that the stiffness and strength of the curved arm can be improved while its weight can be reduced by 10.77%, which shows that it is feasible and promising to achieve a lightweight design of the curved arm of a billet tong. The proposed method can be extended to other equipment with complex working conditions
An Attack on a Fully Homomorphic Encryption Scheme
In this paper we present an attack on a fully homomorphic encryption scheme on PKC2010.
We construct a modi¯ed secret key, a modi¯ed decryption algorithm and a subset of the ciphertext
space. When the ciphertext is from the subset, we can correctly decrypt it by our modi¯ed secret key
and modi¯ed decryption algorithm. We also discuss when our modi¯ed decryption algorithm is e±cient,
and when the subset is not negligible
AN IMPROVED BARE-BONES PARTICLE SWARM ALGORITHM FOR MULTI-OBJECTIVE OPTIMIZATION WITH APPLICATION TO THE ENGINEERING STRUCTURES
In this paper, an improved bare-bones multi-objective particle swarm algorithm is proposed to solve the multi-objective size optimization problems with non-linearity and constraints in structural design and optimization. Firstly, the development of particle individual guide and the randomness of gravity factor are increased by modifying the updated form of particle position. Then, the combination of spatial grid density and congestion distance ranking is used to maintain the external archive, which is divided into two parts: feasible solution set and infeasible solution set. Next, the global best positions are determined by increasing the probability allocation strategy which varies with time. The algorithmic complexity is given and the performance of solution ability, convergence and constraint processing are analyzed through standard test functions and compared with other algorithms. Next, as a case study, a support frame of triangle track wheel is optimized by the BB-MOPSO and improved BB-MOPSO. The results show that the improved algorithm improves the cross-region exploration, optimal solution distribution and convergence of the bare-bones particle swarm optimization algorithm, which can effectively solve the multi-objective size optimization problem with non-linearity and constraints
CMU-Net: A Strong ConvMixer-based Medical Ultrasound Image Segmentation Network
U-Net and its extensions have achieved great success in medical image
segmentation. However, due to the inherent local characteristics of ordinary
convolution operations, U-Net encoder cannot effectively extract global context
information. In addition, simple skip connections cannot capture salient
features. In this work, we propose a fully convolutional segmentation network
(CMU-Net) which incorporates hybrid convolutions and multi-scale attention
gate. The ConvMixer module extracts global context information by mixing
features at distant spatial locations. Moreover, the multi-scale attention gate
emphasizes valuable features and achieves efficient skip connections. We
evaluate the proposed method using both breast ultrasound datasets and a
thyroid ultrasound image dataset; and CMU-Net achieves average Intersection
over Union (IoU) values of 73.27% and 84.75%, and F1 scores of 84.81% and
91.71%. The code is available at https://github.com/FengheTan9/CMU-Net.Comment: This work has been submitted to the IEEE for possible publication.
Copyright may be transferred without notice, after which this version may no
longer be accessibl
DESIGN AND OPTIMIZATION OF THE VARIABLE-DENSITY LATTICE STRUCTURE BASED ON LOAD PATHS
Lattice structure is more and more widely used in engineering by replacing solid structure. But its mechanical performances are constrained by the external shape if the unit cells are directly filled in the design domain, and the traditional topology optimization methods are difficult to give the explicitly mechanical guidance for the distribution of internal unit cells. In this paper, a novel design and optimization method of variable-density lattice structure is proposed in order to simultaneously optimize the external shape and the internal unit cells. First of all, the envelope model of any given structure should be established, and the load paths need to be visualized by the theory of load path. Then, the design criteria of external shape are established based on the principle of smoother load paths in the structure. An index of load flow capacity is defined to indicate the load paths density and to control the density distribution of unit cells, and a detailed optimization strategy is given. Finally, three examples of a cantilever plate, an L-shaped bracket and a classical three-point bending beam are used to verify the method. The results show that the models designed by the proposed method have better mechanical performances, lower material usage and less printing time
CMUNeXt: An Efficient Medical Image Segmentation Network based on Large Kernel and Skip Fusion
The U-shaped architecture has emerged as a crucial paradigm in the design of
medical image segmentation networks. However, due to the inherent local
limitations of convolution, a fully convolutional segmentation network with
U-shaped architecture struggles to effectively extract global context
information, which is vital for the precise localization of lesions. While
hybrid architectures combining CNNs and Transformers can address these issues,
their application in real medical scenarios is limited due to the computational
resource constraints imposed by the environment and edge devices. In addition,
the convolutional inductive bias in lightweight networks adeptly fits the
scarce medical data, which is lacking in the Transformer based network. In
order to extract global context information while taking advantage of the
inductive bias, we propose CMUNeXt, an efficient fully convolutional
lightweight medical image segmentation network, which enables fast and accurate
auxiliary diagnosis in real scene scenarios. CMUNeXt leverages large kernel and
inverted bottleneck design to thoroughly mix distant spatial and location
information, efficiently extracting global context information. We also
introduce the Skip-Fusion block, designed to enable smooth skip-connections and
ensure ample feature fusion. Experimental results on multiple medical image
datasets demonstrate that CMUNeXt outperforms existing heavyweight and
lightweight medical image segmentation networks in terms of segmentation
performance, while offering a faster inference speed, lighter weights, and a
reduced computational cost. The code is available at
https://github.com/FengheTan9/CMUNeXt.Comment: 8 pages, 3 figure
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