Isomorphism Detection of Planar Kinematic Chains With Multiple Joints Using Information Theory

2019 ◽  
Vol 141 (10) ◽  
Author(s):  
Rajneesh Kumar Rai ◽  
Sunil Punjabi
Keyword(s):  
Information Theory ◽  
Structural Similarity ◽  
Transmission Efficiency ◽  
Necessary Condition ◽  
Connectivity Matrix ◽  
Kinematic Chains ◽  
Compact Size ◽  
Independent Loops ◽  
Link Connectivity ◽  
Structural Invariants

Isomorphism (structural similarity) of kinematic chains (KCs) of mechanisms is an important issue in the structural synthesis, which must be identified to avoid the duplicate structures. Duplication causes incorrect family size, i.e., distinct KCs with a given number of links (n) and degree of freedom (dof). Besides simple joints kinematic chains (SJKCs), multiple joints kinematic chains (MJKCs) are also widely used because of their compact size and the methods dealing with such KCs are few. The proposed method deals with two different structural invariants, i.e., primary structural invariants (provide only the necessary condition of isomorphism), such as link connectivity number (LCN) of all the links, link connectivity number of chain (CCN), joint connectivity number (JCN) of all the joints, and joint connectivity number of chain (JCNC), and secondary structural invariants (provide the sufficient condition of isomorphism), such as power transmission (P) and transmission efficiency (Te). Primary structural invariants are calculated using a new link–link connectivity matrix (LLCM), whereas secondary structural invariants are calculated using the concept of entropy of information theory. The method has been successfully tested for 10 and 11 links MJKCs (illustrative examples taken in the paper) and for the families of 18 MJKCs with 8 links, 2 MJs, 1-dof, and 3 independent loops; 22 MJKCs with 8 links, 1 MJ, 1-dof, and 3 independent loops; and 83 MJKCs with 9 links, 1 MJ, 2-dof, and 3 independent loops.

Structure Based Grading of Kinematic Chains

2014 ◽  
Vol 575 ◽  
pp. 501-506 ◽  
Author(s):  
Shubhashis Sanyal ◽  
G.S. Bedi
Keyword(s):  
Structural Properties ◽  
Structural Property ◽  
Kinematic Chain ◽  
Degree Of Freedom ◽  
Kinematic Chains ◽  
Structural Differences ◽  
The Individual ◽  
Independent Loops

Kinematic chains differ due to the structural differences between them. The location of links, joints and loops differ in each kinematic chain to make it unique. Two similar kinematic chains will produce similar motion properties and hence are avoided. The performance of these kinematic chains also depends on the individual topology, i.e. the placement of its entities. In the present work an attempt has been made to compare a family of kinematic chains based on its structural properties. The method is based on identifying the chains structural property by using its JOINT LOOP connectivity table. Nomenclature J - Number of joints, F - Degree of freedom of the chain, N - Number of links, L - Number of basic loops (independent loops plus one peripheral loop).

Algorithm for computing the connectivity in planar kinematic chains and its application

2020 ◽  
pp. 095440622098050
Author(s):  
Wenjian Yang ◽  
Huafeng Ding ◽  
Andres Kecskemethy
Keyword(s):  
Minimum Distance ◽  
Distance Matrix ◽  
Individual Characteristics ◽  
Connectivity Matrix ◽  
Practical Application ◽  
Kinematic Chains ◽  
Main Work ◽  
The Face ◽  
Mobility Matrix ◽  
Connectivity Constraint

The number of synthesized kinematic chains usually is too large to evaluate individual characteristics of each chain. The concept of connectivity is useful to classify the kinematic chains. In this paper, an algorithm is developed to automatically compute the connectivity matrix in planar kinematic chains. The main work is to compute two intermediate parameters, namely the minimum mobility matrix and the minimum distance matrix. The algorithm is capable of dealing with both simple-jointed and multiple-jointed kinematic chains. The present work can be used to automatically determine kinematic chains satisfying the required connectivity constraint, and is helpful for the creative design of mechanisms. The practical application is illustrated by taking the face-shovel hydraulic excavator for instance.

Combined Graph Layout Algorithms for Automated Sketching of Kinematic Chains

2012 ◽  
Author(s):  
Martín A. Pucheta ◽  
Nicolás E. Ulrich ◽  
Alberto Cardona
Keyword(s):  
Computational Cost ◽  
Kinematic Chain ◽  
Initial Position ◽  
Graph Representation ◽  
Combinatorial Algorithms ◽  
Graph Layout ◽  
Kinematic Chains ◽  
Aesthetic Characteristics ◽  
Edge Crossings ◽  
Independent Loops

The graph layout problem arises frequently in the conceptual stage of mechanism design, specially in the enumeration process where a large number of topological solutions must be analyzed. Two main objectives of graph layout are the avoidance or minimization of edge crossings and the aesthetics. Edge crossings cannot be always avoided by force-directed algorithms since they reach a minimum of the energy in dependence with the initial position of the vertices, often randomly generated. Combinatorial algorithms based on the properties of the graph representation of the kinematic chain can be used to find an adequate initial position of the vertices with minimal edge crossings. To select an initial layout, the minimal independent loops of the graph can be drawn as circles followed by arcs, in all forms. The computational cost of this algorithm grows as factorial with the number of independent loops. This paper presents a combination of two algorithms: a combinatorial algorithm followed by a force-directed algorithm based on spring repulsion and electrical attraction, including a new concept of vertex-to-edge repulsion to improve aesthetics and minimize crossings. Atlases of graphs of complex kinematic chains are used to validate the results. The layouts obtained have good quality in terms of minimization of edge crossings and maximization of aesthetic characteristics.

Structure Types Synthesis of Multiloop Spatial Kinematic Chains With General Variable Constraints

1998 ◽  
Author(s):  
Yufeng Luo ◽  
Tingli Yang ◽  
Ali Seireg
Keyword(s):  
Kinematic Chain ◽  
Structure Type ◽  
Type Synthesis ◽  
Kinematic Chains ◽  
Systematic Procedure ◽  
Independent Loops

Abstract A systematic procedure is presented for the structure type synthesis of multiloop spatial kinematic chains with general variable constraints in this paper. The parameters and the structure types of the contracted graphs and the branch chains used to synthesize such kinematic chains are given for kinematic chains with up to four independent loops. The assignments for the constraints values of all the loops in a kinematic chain are discussed. Using these as the basis, the structure types of the multiloop spatial kinematic chains with hybrid constraints could be synthesized.

scholarly journals RF-DC conversion efficiency improvement for microwave transmission with pulse modulation

2019 ◽  
Vol 6 (1) ◽  
pp. 57-66 ◽  
Author(s):  
Takashi Hirakawa ◽  
Ce Wang ◽  
Naoki Shinohara
Keyword(s):  
Conversion Efficiency ◽  
Continuous Wave ◽  
Harmonic Balance Method ◽  
Transmission Efficiency ◽  
Duty Ratio ◽  
Necessary Condition ◽  
Pulse Modulation ◽  
Microwave Transmission ◽  
Output Load ◽  
Modulated Waves

Microwave power transfer (MPT) can solve certain types of problems. For example, Internet of Things requires a flexible configuration of sensor networks, which is hindered by wired-charging sensors. This problem can be overcome by MPT techniques. However, the transmission efficiency of MPT is lower than that of wired transmission. This study focuses on the operation of rectifiers having a pulse-modulated input signal. Although a pulse-modulated wave is effective for improving the RF-DC conversion efficiency, the output voltage waves of rectifiers have a high ripple content. Moreover, the harmonic balance method cannot be used to simulate the operation of a pulse-modulated rectifier. To reduce the ripple content, a smoothing capacitor should be connected in parallel to an output load. We investigated the influence of a smoothing capacitor, the general characteristics of rectifiers under pulse-modulated waves, and the effectiveness of using pulse-modulated waves for improving RF-DC conversion efficiency. In conclusion, we reveal a necessary condition of the smoothing capacitor for improvement, demonstrate the effectiveness of pulse modulation, and show that the optimum impedance with a pulse-modulated wave input is an inverse of duty ratio times as compared to that with continuous wave input.

scholarly journals A Novel Hierarchical Coding Progressive Transmission Method for WMSN Wildlife Images

Sensors ◽  
2019 ◽  
Vol 19 (4) ◽  
pp. 946 ◽  
Author(s):  
Wenzhao Feng ◽  
Chunhe Hu ◽  
Yuan Wang ◽  
Junguo Zhang ◽  
Hao Yan
Keyword(s):  
Signal To Noise Ratio ◽  
Similarity Index ◽  
Structural Similarity ◽  
Transmission Efficiency ◽  
Signal Interference ◽  
Progressive Transmission ◽  
Wireless Multimedia ◽  
Transmission Method ◽  
Hierarchical Coding ◽  
Object Region

In the wild, wireless multimedia sensor network (WMSN) communication has limited bandwidth and the transmission of wildlife monitoring images always suffers signal interference, which is time-consuming, or sometimes even causes failure. Generally, only part of each wildlife image is valuable, therefore, if we could transmit the images according to the importance of the content, the above issues can be avoided. Inspired by the progressive transmission strategy, we propose a hierarchical coding progressive transmission method in this paper, which can transmit the saliency object region (i.e. the animal) and its background with different coding strategies and priorities. Specifically, we firstly construct a convolution neural network via the MobileNet model for the detection of the saliency object region and obtaining the mask on wildlife. Then, according to the importance of wavelet coefficients, set partitioned in hierarchical tree (SPIHT) lossless coding is utilized to transmit the saliency image which ensures the transmission accuracy of the wildlife region. After that, the background region left over is transmitted via the Embedded Zerotree Wavelets (EZW) lossy coding strategy, to improve the transmission efficiency. To verify the efficiency of our algorithm, a demonstration of the transmission of field-captured wildlife images is presented. Further, comparison of results with existing EZW and discrete cosine transform (DCT) algorithms shows that the proposed algorithm improves the peak signal to noise ratio (PSNR) and structural similarity index (SSIM) by 21.11%, 14.72% and 9.47%, 6.25%, respectively.

scholarly journals Integrated Information Theory and Isomorphic Feed-Forward Philosophical Zombies

Entropy ◽  
2019 ◽  
Vol 21 (11) ◽  
pp. 1073 ◽  
Author(s):  
Jake R. Hanson ◽  
Sara I. Walker
Keyword(s):  
Information Theory ◽  
Subjective Experience ◽  
Original System ◽  
Necessary Condition ◽  
Mathematical Framework ◽  
Hard Problem ◽  
The Hard Problem ◽  
Labeling Scheme ◽  
Integrated Information Theory ◽  
Integrated Information

Any theory amenable to scientific inquiry must have testable consequences. This minimal criterion is uniquely challenging for the study of consciousness, as we do not know if it is possible to confirm via observation from the outside whether or not a physical system knows what it feels like to have an inside—a challenge referred to as the “hard problem” of consciousness. To arrive at a theory of consciousness, the hard problem has motivated development of phenomenological approaches that adopt assumptions of what properties consciousness has based on first-hand experience and, from these, derive the physical processes that give rise to these properties. A leading theory adopting this approach is Integrated Information Theory (IIT), which assumes our subjective experience is a “unified whole”, subsequently yielding a requirement for physical feedback as a necessary condition for consciousness. Here, we develop a mathematical framework to assess the validity of this assumption by testing it in the context of isomorphic physical systems with and without feedback. The isomorphism allows us to isolate changes in Φ without affecting the size or functionality of the original system. Indeed, the only mathematical difference between a “conscious” system with Φ > 0 and an isomorphic “philosophical zombie” with Φ = 0 is a permutation of the binary labels used to internally represent functional states. This implies Φ is sensitive to functionally arbitrary aspects of a particular labeling scheme, with no clear justification in terms of phenomenological differences. In light of this, we argue any quantitative theory of consciousness, including IIT, should be invariant under isomorphisms if it is to avoid the existence of isomorphic philosophical zombies and the epistemological problems they pose.

Topological Characteristics and Automatic Generation of Structural Synthesis of Spatial Mechanisms: Part II — Automatic Generation of Structural Types of Kinematic Chains

1992 ◽  
Author(s):  
Ting-Li Yang ◽  
Fang-Hua Yao
Keyword(s):  
Kinematic Chain ◽  
Automatic Generation ◽  
Structural Synthesis ◽  
Kinematic Chains ◽  
Automatic Program ◽  
Spatial Mechanisms ◽  
Structural Types ◽  
Topological Characteristics ◽  
Linear Graphs ◽  
Independent Loops

Abstract Based on the single-opened chain constraints and the network topological characteristics of mechanisms, a powerful new method for structural synthesis of spatial kinematic chain with plane and nonplane linear graphs has been developed. This permits the development of a highly efficient and completely automatic program for the computer-generated enumeration of structural types of mechanisms. The method is illustrated by applying to the case of kinematic chains with up to six independent loops on a personal computer.

Automatic synthesis of the complete set of contracted graphs for planar kinematic chains with up to seven independent loops

2021 ◽  
Vol 156 ◽  
pp. 104144
Author(s):  
Liang Sun ◽  
Rongjiang Cui ◽  
Wenjian Yang ◽  
Zhizheng Ye ◽  
Yuzhu Zhou ◽  
...  
Keyword(s):  
Automatic Synthesis ◽  
Kinematic Chains ◽  
Complete Set ◽  
Independent Loops

A Study on Determining Loops of Planar Kinematic Chains

1994 ◽  
Vol 208 (1) ◽  
pp. 59-63 ◽  
Author(s):  
W Li ◽  
Z Wang ◽  
H Li
Keyword(s):  
Kinematic Chain ◽  
Automatic Generation ◽  
Maximum Length ◽  
Small Length ◽  
Kinematic Chains ◽  
New Concepts ◽  
Large Length ◽  
First Time ◽  
Independent Loops

This paper presents for the first time a method for the automatic generation of independent and peripheral loops of planar kinematic chains. In order to implement this method, three laws are considered and some new concepts, for instance same-position link, similar loop, loop-link vector and loop-joint vector, are defined. By using structural matrices of planar kinematic chains, independent loops are generated in the order from those with small length to those with large length. Next, one peripheral loop with the maximum length is generated. Finally a loop-link matrix and a loop-joint matrix are obtained to express all independent loops and the peripheral loop in a planar kinematic chain.

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