The Stratified Representation of Mechanisms

1990 ◽  
Vol 112 (4) ◽  
pp. 514-519 ◽  
Author(s):  
W. E. Fang ◽  
F. Freudenstein
Keyword(s):  
Characteristic Polynomial ◽  
Structural Information ◽  
Traditional Approach ◽  
Structural Characteristics ◽  
New Method ◽  
Kinematic Structure ◽  
Kinematic Chains ◽  
Order Of Magnitude

A new method for the representation of the kinematic structure of mechanisms has been proposed. This scheme is an order-of-magnitude faster in enumerating mechanisms than the conventional characteristic-polynomial approach. Moreover, unlike the traditional approach, it never fails to identify a mechanism and all structural information relating to the mechanism can be retrieved from this representation. Classification of mechanisms based on structural characteristics is built-in as well. Using this method, the graphs of approximately one million kinematic chains have been generated and stored in a computer.

scholarly journals Structural Synthesis of Articulated Manipulators with Non-Fractionated or Fractionated Kinematic Chains without Isomorphism

2021 ◽  
Vol 11 (20) ◽  
pp. 9658
Author(s):  
Ho Sung Park ◽  
Jae Kyung Shim ◽  
Woon Ryong Kim ◽  
Tae Woong Yun
Keyword(s):  
Structural Characteristics ◽  
Kinematic Chain ◽  
Kinematic Structure ◽  
Free Graph ◽  
Kinematic Chains ◽  
Conceptual Design Phase ◽  
Fixed Base ◽  
Force Transmissibility ◽  
Isomorphic Graphs ◽  
Two Degree Of Freedom

As the kinematic structure of an articulated manipulator affects the characteristics of its motion, rigidity, vibration, and force transmissibility, finding the most suitable kinematic structure for the desired task is important in the conceptual design phase. This paper proposes a systematic method for generating non-isomorphic graphs of articulated manipulators that consist of a fixed base, an end-effector, and a two-degree-of-freedom (DOF) intermediate kinematic chain connecting the two. Based on the analysis of the structural characteristics of articulated manipulators, the conditions that must be satisfied for manipulators to have a desired DOF is identified. Then, isomorphism-free graph generation methods are proposed based on the concepts of the symmetry of a graph, and the number of graphs generated are determined. As a result, 969 graphs of articulated manipulators that have two-DOF non-fractionated intermediate kinematic chains and 33,438 graphs with two-DOF fractionated intermediate kinematic chains are generated, including practical articulated manipulators widely used in industry.

Efficient and High-Quality Seeded Graph Matching: Employing Higher-order Structural Information

2021 ◽  
Vol 15 (3) ◽  
pp. 1-31
Author(s):  
Haida Zhang ◽  
Zengfeng Huang ◽  
Xuemin Lin ◽  
Zhe Lin ◽  
Wenjie Zhang ◽  
...  
Keyword(s):  
Large Scale ◽  
Graph Matching ◽  
Structural Information ◽  
Experimental Studies ◽  
Higher Order ◽  
Personalized Pagerank ◽  
Matching Accuracy ◽  
Approximation Techniques ◽  
Order Of Magnitude ◽  
Matching Score

Driven by many real applications, we study the problem of seeded graph matching. Given two graphs and , and a small set of pre-matched node pairs where and , the problem is to identify a matching between and growing from , such that each pair in the matching corresponds to the same underlying entity. Recent studies on efficient and effective seeded graph matching have drawn a great deal of attention and many popular methods are largely based on exploring the similarity between local structures to identify matching pairs. While these recent techniques work provably well on random graphs, their accuracy is low over many real networks. In this work, we propose to utilize higher-order neighboring information to improve the matching accuracy and efficiency. As a result, a new framework of seeded graph matching is proposed, which employs Personalized PageRank (PPR) to quantify the matching score of each node pair. To further boost the matching accuracy, we propose a novel postponing strategy, which postpones the selection of pairs that have competitors with similar matching scores. We show that the postpone strategy indeed significantly improves the matching accuracy. To improve the scalability of matching large graphs, we also propose efficient approximation techniques based on algorithms for computing PPR heavy hitters. Our comprehensive experimental studies on large-scale real datasets demonstrate that, compared with state-of-the-art approaches, our framework not only increases the precision and recall both by a significant margin but also achieves speed-up up to more than one order of magnitude.

scholarly journals Improving MUSLE performance for sediment yield prediction at micro-watershed level using seasonal classified data

2018 ◽  
Vol 13 (3) ◽  
pp. 505-512
Author(s):  
Hamzeh Noor ◽  
Mohammad Rostami Khalaj
Keyword(s):  
Sediment Yield ◽  
Traditional Approach ◽  
Estimation Error ◽  
Superior Performance ◽  
North East ◽  
Erosion Processes ◽  
The North ◽  
East Of Iran ◽  
Different Seasons

Abstract Separating erosion data and assessing season-based models are of great importance considering the variation in soil erosion processes in different seasons, especially in semi-arid regions. However, evaluation of an erosion model using seasonal classification of data and at a micro-watershed level have rarely been considered. Therefore, the present study was conducted to evaluate the modified universal soil loss equation (MUSLE): 1) with the seasonal classification of data and 2) with the traditional approach (no classification of data), in the Sanganeh research micro-watershed. This watershed has an area of 1.2 ha and is located in the north east of Iran. The results showed that the original MUSLE overestimated the sediment yield in the study watershed. Also, after calibration of MUSLE, the seasonal classification of data (with a relative estimation error (RE) of 34%) showed its superior performance compared with the traditional calibration approach (with a RE of 62%). In this regard, the obtained REs of 33, 40, and 31% respectively for spring, autumn, and winter are within or close to the acceptable range.

Pseudo-three-timescale approximation of exponentially modulated free-surface waves

2009 ◽  
Vol 625 ◽  
pp. 435-443 ◽  
Author(s):  
MARK A. KELMANSON
Keyword(s):  
Free Surface ◽  
Surface Waves ◽  
Test Problem ◽  
Evolution Equations ◽  
Film Coating ◽  
Rotating Cylinder ◽  
New Method ◽  
Free Surface Waves ◽  
Numerical Integrations ◽  
Order Of Magnitude

A novel pseudo-three-timescale asymptotic procedure is developed and implemented for obtaining accurate approximations to solutions of an evolution equation arising in thin-film free-surface viscous flow. The new procedure, which employs strained fast and slow timescales, requires considerably fewer calculations than its standard three-timescale counterpart employing fast, slow and slower timescales and may readily be applied to other evolution equations of fluid mechanics possessing wave-like solutions exhibiting exponential decay in amplitude and variations in phase over disparate timescales. The new method is validated on the evolution of free-surface waves on a thin, viscous film coating the exterior of a horizontal rotating cylinder and is shown to yield accurate solutions up to non-dimensional times exceeding by an order of magnitude those of previous related studies. Results of the new method applied to this test problem are demonstrated to be in excellent agreement, over large timescales, with those of corroborative spectrally accurate numerical integrations.

scholarly journals Prima facie duties and the structure of ethical explanations

2019 ◽  
Vol 62 (3) ◽  
pp. 53-64
Author(s):  
Monika Jovanovic
Keyword(s):  
Structural Characteristics ◽  
Prima Facie ◽  
Moral Reasons ◽  
Ethical Theories ◽  
Problematic Case ◽  
Normative Implications

I begin with the thesis that the most appropriate classification of ethical theories pertains to their structural characteristics and give the advantage to the particularism/ generalism dichotomy over the deontological/teleological and act-centered/agent-centered classifications. Subsequently I use the example of Ross?s ethics of prima facie duties to illustrate how this distinction can be properly applied to a seemingly problematic case. In the first part of the paper I aim to show that Ross?s view is, in spite of its use of deontological terminology, essentially particularist. I then examine the specificities of Ross?s pluralism and explore the connection between prima facie duties and normative moral reasons. In the second part of the paper I criticize Audi?s interpretation of Ross?s ethics and show that Ross?s view doesn?t have the normative implications that Audi ascribes to it.

scholarly journals Structure insights of the human peroxisomal ABC transporter ALDP

2021 ◽  
Author(s):  
Yutian Jia ◽  
Yanming Zhang ◽  
Jianlin Lei ◽  
Guanghui Yang
Keyword(s):  
Structural Information ◽  
Free State ◽  
Head Group ◽  
Working Mechanism ◽  
Peroxisomal Membrane ◽  
Binding Domains ◽  
Cryo Electron Microscopy ◽  
Ligand Free ◽  
Clinical Description

Adrenoleukodystrophy protein (ALDP) is responsible for the transport of free very-long-chain fatty acids (VLCFAs) and corresponding CoA-esters across the peroxisomal membrane. ALDP belongs to the ATP-binding cassette sub-family D, which is also named as ABCD1. Dysfunction of ALDP leads to peroxisomal metabolic disorder exemplified by X-linked adrenoleukodystrophy (ALD). Hundreds of ALD-causing mutations are identified on ALDP. However, the pathogenic mechanisms of these mutations are restricted to clinical description due to limited structural information. Furthermore, ALDP plays a role in myelin maintenance, which is tightly associated with axon regeneration. Here we report the cryo-electron microscopy (cryo-EM) structure of human ALDP with nominal resolution of 3.4 angstrom in nucleotide free state. The structure of ALDP exhibits a typical assembly of ABC transporters. The nucleotide binding domains (NBDs) displays a ligand free state. ALDP exhibits an inward-open conformation to the cytosol. A short helix is located at the peroxisomal side, which is different from other three members of ABCD transporters. The two transmembrane domains (TMDs) of ALDP form a cavity, in which two lipid-like densities can be recognized as the head group of an coenzyme-A ester of a lipid. This structure provides a framework for understanding the working mechanism of ALDP and classification of the disease-causing mutations.

scholarly journals High Molecular Weight Kininogen Peptides Inhibit the Formation of Kallikrein on Endothelial Cell Surfaces and Subsequent Urokinase-Dependent Plasmin Formation

Blood ◽  
1997 ◽  
Vol 90 (2) ◽  
pp. 690-697 ◽  
Author(s):  
Yingzhang Lin ◽  
Robert B. Harris ◽  
Wuyi Yan ◽  
Keith R. McCrae ◽  
Hong Zhang ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Structural Information ◽  
Umbilical Vein ◽  
High Molecular Weight Kininogen ◽  
Cell Surfaces ◽  
Free System ◽  
Order Of Magnitude ◽  
A Cell ◽  
Umbilical Vein Endothelial Cells

A sequence of 31 amino acids (S565-K595) in domain 6 of the light chain of high molecular weight kininogen (HK) has previously been shown to be responsible for the binding of plasma prekallikrein (PK) or kallikrein. To find effective peptides that might block binding between HK and PK on cell surfaces, a new series of synthetic peptides has now been prepared that incorporates portions of this binding domain sequence. For mapping the minimal sequence within HK, these new peptides were tested for their ability to compete with HK for binding PK in a cell-free system and on human umbilical vein endothelial cells (HUVEC). In the former, at pH 7.4, the kds for binding between kallikrein and either D567-K595, S565-P594, D567-S593, or D567-T591 were all similar to that for the binding of S565-K595 (0.2 to 0.4 μmol/L), but those for the binding of D568-K595, W569-K595, and D567-P589 were an order of magnitude greater (kd = 2 to 5 μmol/L). D567-S586, the shortest chain length of the N- and C-terminal truncation sequences tested, does not effectively compete with kininogen for kallikrein binding (kd = 100 μmol/L). These results imply that D567-T591, a 25-residue peptide (HK25c), contains sufficient structural information for binding kallikrein in solution. D567-T591 also is the minimum structural sequence to block binding of kallikrein to HUVEC-bound HK (IC50 = 50 nmol/L) and to inhibit PK activation to kallikrein on the cell surface (IC50 = 80 nmol/L). In addition, D567-T591 also inhibits the generation of kallikrein-activated urokinase, which activates plasminogen to plasmin (IC50 = 100 nmol/L). Thus, HK-derived peptides may be useful compounds for modulating excessive fibrinolysis and hypotension in sepsis and multiple trauma.

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