132 research outputs found
Verification and Enforcement of Strong State-Based Opacity for Discrete-Event Systems
In this paper, we investigate the verification and enforcement of strong
state-based opacity (SBO) in discrete-event systems modeled as
partially-observed (nondeterministic) finite-state automata, including strong
K-step opacity (K-SSO), strong current-state opacity (SCSO), strong
initial-state opacity (SISO), and strong infinite-step opacity (Inf-SSO). They
are stronger versions of four widely-studied standard opacity notions,
respectively. We firstly propose a new notion of K-SSO, and then we construct a
concurrent-composition structure that is a variant of our previously-proposed
one to verify it. Based on this structure, a verification algorithm for the
proposed notion of K-SSO is designed. Also, an upper bound on K in the proposed
K-SSO is derived. Secondly, we propose a distinctive opacity-enforcement
mechanism that has better scalability than the existing ones (such as
supervisory control). The basic philosophy of this new mechanism is choosing a
subset of controllable transitions to disable before an original system starts
to run in order to cut off all its runs that violate a notion of strong SBO of
interest. Accordingly, the algorithms for enforcing the above-mentioned four
notions of strong SBO are designed using the proposed two
concurrent-composition structures. In particular, the designed algorithm for
enforcing Inf-SSO has lower time complexity than the existing one in the
literature, and does not depend on any assumption. Finally, we illustrate the
applications of the designed algorithms using examples.Comment: 30 pages, 20 figures, partial results in Section 3 were presented at
IEEE Conference on Decision and Control, 2022. arXiv admin note: text overlap
with arXiv:2204.0469
Robust Image Analysis by L1-Norm Semi-supervised Learning
This paper presents a novel L1-norm semi-supervised learning algorithm for
robust image analysis by giving new L1-norm formulation of Laplacian
regularization which is the key step of graph-based semi-supervised learning.
Since our L1-norm Laplacian regularization is defined directly over the
eigenvectors of the normalized Laplacian matrix, we successfully formulate
semi-supervised learning as an L1-norm linear reconstruction problem which can
be effectively solved with sparse coding. By working with only a small subset
of eigenvectors, we further develop a fast sparse coding algorithm for our
L1-norm semi-supervised learning. Due to the sparsity induced by sparse coding,
the proposed algorithm can deal with the noise in the data to some extent and
thus has important applications to robust image analysis, such as noise-robust
image classification and noise reduction for visual and textual bag-of-words
(BOW) models. In particular, this paper is the first attempt to obtain robust
image representation by sparse co-refinement of visual and textual BOW models.
The experimental results have shown the promising performance of the proposed
algorithm.Comment: This is an extension of our long paper in ACM MM 201
EnergyâEfficient OilâWater Separation of Biomimetic Copper Membrane with Multiscale Hierarchical Dendritic Structures
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138424/1/smll201701121-sup-0001-S1.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138424/2/smll201701121_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138424/3/smll201701121.pd
Superfast Liquid Transfer Strategy Through Sliding on a Liquid Membrane Inspired from Scorpion Setae
Although diversified biological structures have evolved fog collection abilities, the typical speeds of the condensed water droplets on these surfaces are too slow to have practical utility. The main challenge focuses on the elimination of the interfacial hydrodynamic resistance without external energy support. Here, an unusual strategy for superfast selfâsupport transfer condensed droplets is supported by sliding on seta of desert scorpion. It can be rapidly wetted by the fog droplets owing to its conical shape with linear gradient channels. A loss of interfacial resistance by this hydrodynamically lubricating water membrane could significantly accelerate the movement of the droplets, thus making its velocity increasing by one order of magnitude, or even more. Inspired by this novel strategy, the novel bioinspired materials are fabricated with the similar gradient channel structures and droplet transportation mode, which can make the condensed droplets spontaneously slide on the lowâfriction liquid membrane. The fundamental understanding of superfast fog capture and the sliding dynamics of condensed droplets in this system could inspire to develop novel materials or various systems to transfer liquid fast and efficiently without external energy support.An unusual strategy for superfast transferring condensed droplets by sliding on liquid membrane of desert scorpion seta is reported. A loss of interfacial resistance could significantly accelerate the droplets by this hydrodynamically lubricating liquid membrane. Then, the bioinspired materials with similar droplet transportation mode are fabricated, which will inspire to develop novel materials to transport liquid without external energy.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146306/1/admi201800802-sup-0001-S1.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146306/2/admi201800802.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146306/3/admi201800802_am.pd
On the design evolution of hip implants: A review
This manuscript reviews the development of femoral stem prostheses in the biomedical field. After a brief introduction on the development of these prostheses and the associated problems, we describe the standard design of these systems. We review the different materials, constructions, and surfaces used in the development of femoral stems, in order to solve and avoid various problems associated with their use. Femoral stem prostheses have undergone substantial changes and design optimizations since their introduction. Common materials include stainless steel, cobaltâchromium alloy, titanium alloy, and composites. The structural development of femoral stem prostheses, including their length, shape, porosity, and functional gradient construction, is also reviewed. The performance of these prostheses is affected not only by individual factors, but also by the synergistic combination of multiple effects; therefore, several aspects need to be optimized. The main purpose of this study is to summarize various strategies for the material and construction optimization of femoral stem prostheses, and to provide a reference for the combined optimization of their performance. Substantial research is still needed to develop prostheses emulating the behavior of a real human femoral stem
Review and Classification of Bio-inspired Algorithms and Their Applications
Scientists have long looked to nature and biology in order to understand and model solutions for complex real-world problems. The study of bionics bridges the functions, biological structures and functions and organizational principles found in nature with our modern technologies, numerous mathematical and metaheuristic algorithms have been developed along with the knowledge transferring process from the lifeforms to the human technologies. Output of bionics study includes not only physical products, but also various optimization computation methods that can be applied in different areas. Related algorithms can broadly be divided into four groups: evolutionary based bio-inspired algorithms, swarm intelligence-based bio-inspired algorithms, ecology-based bio-inspired algorithms and multi-objective bio-inspired algorithms. Bio-inspired algorithms such as neural network, ant colony algorithms, particle swarm optimization and others have been applied in almost every area of science, engineering and business management with a dramatic increase of number of relevant publications. This paper provides a systematic, pragmatic and comprehensive review of the latest developments in evolutionary based bio-inspired algorithms, swarm intelligence based bio-inspired algorithms, ecology based bio-inspired algorithms and multi-objective bio-inspired algorithms
An Evil Backstage Manipulator: Psychological Factors Correlated with Health-Related Quality of Life in Chinese Patients with Crohn's Disease
Health-related quality of life (HRQoL) is recommended as one of essential parameters to evaluate treatment effect and clinical outcome in patients with Crohn's disease (CD). Recent studies reported that psychological factors might play a role in HRQoL in Western and American CD patients. Sufficient evidences in Chinese CD patients are still unavailable. This study is dedicated to investigate the correlation of various psychological factors with HRQoL in Chinese CD patients. We prospectively collected 40 active and 40 quiescent CD patients in China and found that psychological factors, especially neuroticism and anxiety, significantly correlate with and affect HRQoL in both active and quiescent CD groups. This is the first report revealing correlation between psychological factors and HRQoL in Chinese CD patients. Therefore, we assume that our results can contribute to a better understanding of etiology and tailoring of management in Chinese patients with Crohn's disease and are beneficial to our colleagues to compare the heterogeneous characteristics of Crohn's disease in different ethnic groups
Genome-wide identification and comprehensive analysis of tubby-like protein gene family in multiple crops
IntroductionThe highly conserved tubby-like proteins (TLPs) play key roles in animal neuronal development and plant growth. The abiotic stress tolerance function of TLPs has been widely explored in plants, however, little is known about comparative studies of TLPs within crops.MethodsBioinformatic identification, phylogenetic analysis, Cis-element analysis, expression analysis, Cis-element analysis, expression analysis and so on were explored to analysis the TLP gene family of multiple crops.ResultsIn this study, a comprehensive analysis of TLP genes were carried out in seven crops to explore whether similar function of TLPs in rice could be achieved in other crops. We identified 20, 9, 14, 11, 12, 35, 14 and 13 TLP genes in Glycine max, Hordeum vulgare, Sorghum bicolor, Arabidopsis thaliana, Oryza sativa Japonica, Triticum aestivum, Setaria italic and Zea mays, respectively. All of them were divided into two groups and ten orthogroups (Ors) based on amino acids. A majority of TLP genes had two domains, tubby-like domain and F-box domain, while members of Or5 only had tubby-like domain. In addition, Or5 had more exons and shorter DNA sequences, showing that characteristics of different Ors reflected the differentiated function and feature of TLP genes in evolutionary process, and Or5 was the most different from the other Ors. Besides, we recognized 25 cis-elements in the promoter of TLP genes and explored multiple new regulation pathway of TLPs including light and hormone response. The bioinformatic and transcriptomic analysis implied the stresses induced expression and possible functional redundancy of TLP genes. We detected the expression level of 6 OsTLP genes at 1 to 6 days after seed germination in rice, and the most obvious changes in these days were appeared in OsTLP10 and OsTLP12.DiscussionCombined yeast two-hybrid system and pull down assay, we suggested that the TLP genes of Or1 may have similar function during seed germination in different species. In general, the results of comprehensive analysis of TLP gene family in multiple species provide valuable evolutionary and functional information of TLP gene family which are useful for further application and study of TLP genes
Non-wet kingfisher flying in the rain: The tumble of droplets on moving oriented anisotropic superhydrophobic substrates
Extensive studies of antiwetting have been restricted to stationary substrates, while dewetting mechanisms on moving interfaces are still poorly understood. Due to the hydrophobic and anisotropic surface characteristics of kingfishers, they are able to easily change flight direction even under high-intensity precipitation. The present study aims to mechanistically analyze how the synergy of interfacial movement, anisotropy, and superhydrophobicity affects rapid dehydration. We have designed a droplet-conveyor system to simulate the bouncing of droplets on moving anisotropic superhydrophobic targets and performed simulations via the lattice Boltzmann algorithm. The moving interface can induce a directional tumbling behavior of the droplet and effectively avoid continuous wetting in the same region. We found that droplet tumbling is essentially caused by transformed depinning velocity vectors at the interface downstream. Also, the hang time of a tumbling droplet is positively related to the angle between the motion vector and the texture. The oriented anisotropic motion facilitates the tumbling of droplets and decreases their hang time by up to 23% as compared to that on a stationary inclined superhydrophobic surface. Similar interfacial process dehydration also occurs on a nonwet kingfisher flying in the rain, and we believe that these findings provide valuable new insights for high-efficiency water repellency of surface
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