Mobility of Single Loop Linkages: A Final Word?

2007 ◽  
Author(s):  
Jose´ Mari´a Rico ◽  
J. Jesu´s Cervantes ◽  
Juan Rocha ◽  
Jaime Gallardo ◽  
Luis Daniel Aguilera ◽  
...  
Keyword(s):  
Mobility Analysis ◽  
Additional Insight ◽  
Final Word ◽  
Single Loop ◽  
Kinematic Chains ◽  
Recent Developments ◽  
The Subject ◽  
Insight Into

Setting aside paradoxical linkages such as Bennett’s, Bricard’s or Goldberg’s, the mobility of single loop linkages seemed, with the developments on mobility analysis carried out in the last five years, a closed chapter in kinematic research. However, recent developments on the mobility of parallel platforms have shed additional insight into the problem. This contribution attempts to unify the results obtained in the last five years in the area of mobility of single-loop kinematic chains to state what appears to be a final word on the subject.

Virtual Chain Approach for Mobility Analysis of Multiloop Deployable Mechanisms

2013 ◽  
Vol 135 (11) ◽  
Author(s):  
Hailin Huang ◽  
Zongquan Deng ◽  
Xiaozhi Qi ◽  
Bing Li
Keyword(s):  
Relative Motion ◽  
Twist Angle ◽  
Open Loop ◽  
Mobility Analysis ◽  
Link Length ◽  
Flexible Links ◽  
Single Loop ◽  
Kinematic Chains ◽  
In Series ◽  
Insight Into

In this paper, we present a virtual chain approach for the mobility analysis of multiloop deployable mechanisms. First, the relative motion of the links of single-loop units in multiloop mechanisms are analyzed using the equivalent motion of certain types of open-loop virtual kinematic chains; these kinematic chains comprise some types of joints connected in series by flexible links. This reveals that the links in these virtual chains are not rigid when the mechanism is moving. The parameters of these virtual kinematic chains (such as the link length, the twist angle of two adjacent revolute joint axes, and so on) are variable. By using this approach that involves equivalent kinematic chains, the multiloop mechanisms can be considered equivalent to single-loop mechanisms with flexible links; the closure equations of such multiloop mechanisms can also be derived. The analytical procedures are explained using examples of multiloop mechanisms in which Myard mechanisms as used as the basic single-loop units. A prototype is also fabricated to demonstrate the feasibility of the proposed multiloop mechanism. The proposed method yields a more intuitive and straightforward insight into the mobility of complicated multiloop mechanisms.

scholarly journals Teaching Object-Oriented Programming is more than teaching: Object-Oriented Programming Languages

1988 ◽  
Vol 17 (251) ◽  
Author(s):  
Jørgen Lindskov Knudsen ◽  
Ole Lehrmann Madsen
Keyword(s):  
Programming Languages ◽  
Theoretical Foundation ◽  
Object Oriented ◽  
Research Area ◽  
Object Oriented Programming ◽  
Additional Insight ◽  
Solid Ground ◽  
Approach To Teaching ◽  
The Subject ◽  
Insight Into

<p>One of the important obligations of an expanding research area is to discuss how to approach the teaching of the subject. Without this discussion, we may find that the word is not spread properly, and thus that the results are not properly utilized in in dustry. Furthermore, discussing teaching the research area gives additional insight into the research area and its underlying theoretical foundation. In this paper we will report on our approach to teaching programming languages as a whole and especially teaching object-oriented programming.</p><p>The prime message to be told is that working from a theoretical foundation pays off. Without a theoretical foundation, the discussions are often centered around features of different languages. With a foundation, discussions may be conducted on solid ground. Furthermore, the students have significantly fewer difficulties in grasping the concrete programming languages when they have been presented with the theoretical foundation than without it.</p>

A brief history and recent developments in day‐of‐the‐week effect literature

2011 ◽  
Vol 37 (9) ◽  
pp. 808-816 ◽  
Author(s):  
James Philpot ◽  
Craig A. Peterson
Keyword(s):  
Research Question ◽  
Weekend Effect ◽  
Content Type ◽  
Recent Developments ◽  
Research Findings ◽  
The Subject ◽  
Day Of The Week ◽  
Practical Implications ◽  
Effect Literature ◽  
Insight Into

PurposeThe purpose of this paper is to provide a brief review of pre‐2003 work on the weekend effect and then discuss how recent selected work has extended our knowledge of the subject.Design/methodology/approachResults of recently published studies are organized and summarized by research question and outcomes.FindingsWhile early literature found a fairly consistent weekend effect, with positive returns on Fridays and negative returns on Mondays, more recent research shows the effect moving to other days, reversing or vanishing.Research limitations/implicationsWhile it is difficult to compare studies made across different time periods, the direction of present research gives insight into how markets are adjusting to the weekend effect anomaly.Practical implicationsInvestors may find it very hard to adequately identify a trading strategy based on current research.Originality/valueThis work conveniently synthesizes and presents current research findings from a variety of published sources.

An Essay on the Heat of Transport in Solids and a Partial Guide to the Literature

2015 ◽  
Vol 4 ◽  
pp. 57-68 ◽  
Author(s):  
A.B. Lidiard
Keyword(s):  
Soret Effect ◽  
Transport Coefficients ◽  
Simulation Method ◽  
Transport Parameters ◽  
Additional Insight ◽  
Heat Of Transport ◽  
Materials Modelling ◽  
The Subject ◽  
The One ◽  
Insight Into

This article reviews the subject of the Soret effect and Thermodiffusion in solids more generally. In doing so it draws upon computer simulations made with a method (the Grout-Gillan method) derived from the Green-Kubo approach to transport coefficients in solids. The insights into the make-up of heats of transport parameters, Q*, so obtained are described and used to provide additional insight into measured heats of transport in situations where no reliable theories or simulations exist. These insights also point to the relations between heats of transport on the one hand and phonon thermal conductivity and focussed collision sequences on the other. These relations point to circumstances where the heat of transport may be small (e.g. low coordination in the lattice) or can be estimated from heats of activation for atom movements. In other cases the Grout-Gillan simulation method may offer the most reliable approach. These new insights are expected to be useful in materials modelling.

A Systematic Formulation of Overconstraint Conditions in Kinematic Chains by Displacement Groups

2005 ◽  
Author(s):  
Carlo Galletti ◽  
Pietro Fanghella ◽  
Elena Giannotti
Keyword(s):  
Dynamic Analysis ◽  
Systematic Approach ◽  
Computer Code ◽  
Computer Implementation ◽  
Mobility Analysis ◽  
Kinematic Synthesis ◽  
Single Loop ◽  
Kinematic Chains ◽  
Geometric Data ◽  
Systematic Formulation

The paper describes a systematic approach to define geometrical and dimensional overconstraint conditions for single-loop kinematic chains of both “banal” and “exceptional” types. The approach is an application of the theory of displacement groups. It presents several interesting features: it can be easily integrated with mobility analysis; it makes use of geometric data local to links and does not require a preliminary mechanism assembly nor a given initial congruent position; it is systematic and can be suitably implemented in a computer code; it suggests where geometrical and dimensional tolerances have to be located; it can be embedded in other group-based approaches, like kinematic synthesis or dynamic analysis. After a brief summary of the properties of displacement groups and their operations, the paper shows how they can be used to formulate systematically the overconstraint conditions in kinematic chains. A computer implementation of the approach is also outlined, and several examples with different complexities are given.

Mobility Analysis of Symmetric Deployable Mechanisms Involved in a Coplanar 2-Twist Screw System

2015 ◽  
Vol 8 (1) ◽  
Author(s):  
Bing Li ◽  
Hailin Huang ◽  
Zongquan Deng
Keyword(s):  
Traditional Approach ◽  
Mobility Analysis ◽  
Kinematic Chains ◽  
Insight Into

In this paper, an intuitive approach for the mobility analysis of deployable mechanisms involved in a special screw system with two coplanar twist vectors is proposed. First, the coplanar screw system with a pair of parallel/concurrent zero pitch screws is analyzed, and the intuitive allowable mobility set for the screw system is described. Next, kinematic chains containing the coplanar screw system are enumerated. The proposed approach is used to explain the mobility of the deployable Bennett mechanism, Myard mechanism, and Bricard mechanism; some novel deployable mechanisms could be found based on the analysis. Furthermore, it is shown that the proposed approach can be applied to the mobility analysis of multiloop deployable mechanisms and is found to be more intuitive than the traditional approach, which provides a straightforward insight into the mobility of complicated mechanisms.

Mobility Analysis of Parallel Mechanisms Based on Screw Theory and the Concept of Equivalent Serial Kinematic Chain

2005 ◽  
Author(s):  
Xianwen Kong ◽  
Cle´ment M. Gosselin
Keyword(s):  
Systematic Approach ◽  
Screw Theory ◽  
Kinematic Chain ◽  
Second Step ◽  
Parallel Mechanisms ◽  
Mobility Analysis ◽  
Single Loop ◽  
Kinematic Chains ◽  
Serial Chain ◽  
Parallel Kinematic

This paper presents a systematic approach for the mobility analysis of parallel mechanisms. The method is based on screw theory and the concept of equivalent serial chain. An equivalent serial kinematic chain of a k-legged PKC (parallel kinematic chain) is defined as a serial kinematic chain which has the same twist system and the wrench system as the k-legged PKC. Using the proposed approach, the mobility analysis of a PKC is performed in two steps. The first step is the instantaneous mobility analysis, and the second step is the full-cycle mobility inspection. The first step is dealt with based on screw theory. The second step is performed with the aid of the concept of equivalent serial chain and the types of multi-DOF overconstrained single-loop kinematic chains. The proposed approach is illustrated with several examples.

Events and festivals in Asia and the Middle East/North Africa (MENA) region

2012 ◽  
Vol 3 (1) ◽  
pp. 4-8 ◽  
Author(s):  
Karin Weber ◽  
Jane Ali‐Knight
Keyword(s):  
Mena Region ◽  
Content Type ◽  
Qualitative Approaches ◽  
Recent Developments ◽  
Individual Contributions ◽  
Key Issues ◽  
The Subject ◽  
The Individual ◽  
Insight Into ◽  
Selection Of

PurposeThis editorial aims to provide a brief overview of recent developments in the events industry in general, and in Asia and the MENA region in particular. The discussion forms a prelude for the individual contributions of this special issue.Design/methodology/approachThe papers cover a variety of different research methods and methodologies including both quantitative and qualitative approaches.FindingsSetting the stage for the selection of papers is a thought‐provoking introduction, followed by six papers that aim to provide insights into key issues by examining pertinent literature, addressing relevant research questions, and providing applied and theoretical outcomes relevant to both academics and practitioners in the event and festival fields. These papers cover the variety, scope and diversity of events in Asia and MENA region, with a mixture of papers that examine event‐specific aspects and those that approach the subject from a broader destination/policy perspective.Originality/valueThe selection of papers are unique as they provide a thorough and extensive insight into the opportunities and challenges facing emergent festival and event destinations in Asia and the MENA region.

Synthesis of Deployable/Foldable Single Loop Mechanisms With Revolute Joints

2011 ◽  
Vol 3 (3) ◽  
Author(s):  
Zongquan Deng ◽  
Hailin Huang ◽  
Bing Li ◽  
Rongqiang Liu
Keyword(s):  
Computer Aided Design ◽  
Geometric Approach ◽  
Mobility Analysis ◽  
Design Models ◽  
Single Loop ◽  
Kinematic Chains ◽  
Design And Synthesis ◽  
Revolute Joints ◽  
Computer Aided ◽  
Aided Design

This paper presents a geometric approach for design and synthesis of deployable/foldable single loop mechanisms with pure revolute joints. The basic kinematic chains with symmetric mobility are first synthesized, and an intuitive geometric method is proposed for the mobility analysis of these kinematic chains. The deployable/foldable single loop mechanisms can be regarded as a combination of the basic kinematic chains with nontrivial mobility intersection, under this approach, the 5R to 8R single loop mechanisms with symmetric mobility are synthesized systematically. The method for determining the positions of the joint axes on polyhedral links is also proposed, so that the mechanism can be fully deployed or fully folded without suffering from physical interference. Under this framework, a class of novel deployable/foldable single loop mechanisms is developed. The computer-aided design models for typical examples are built to illustrate their feasibility.

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