Trajectory compensation for multi-robot coordinated lifting system considering elastic catenary of the rope

The multi-robot coordinated lifting system is an unconstrained system with a rigid and flexible coupling.The deformation of the flexible rope causes errors in the movement trajectory of the lifting system.Based on the kinematic and dynamic analysis of the lifting system,the elastic catenary mod-el considering the elasticity and mass of the flexible rope is established,and the effect of the deform-ation of the flexible rope on the position and posture of the suspended object is analyzed.According to the deformation of flexible rope,a real-time trajectory compensation method is proposed based on the compensation principle of position and posture.Under the lifting task of the low-speed move-ment,this is compared with that of the system which neglects the deformation of the flexible rope.The trajectoy of the lifting system considering the deformation of flexible rope.The results show that the mass and elasticity of the flexible rope can not be neglected.Meanwhile,the proposed trajectory compensation method can improve the movement accuracy of the lifting system,which verifies the ef-fectiveness of this compensation method.The research results provide the basis for trajectory plan-ning and coordinated control of the lifting system。

RAO Logic for Multiagent Framework

In this paper, we deal with how agents reason about knowledgeof others in multiagent system. We first present a knowledge representation frame-work called reasoning about others (RAO) which is designed specifically to representconcepts and rules used in reasoning about knowledge of others. From a class ofsentences usually taken by people in daily life to reason about others, a rule calledposition exchange principle (PEP) is abstracted. PEP is described as an axiomscheme in RAO and regarded as a basic rule for agents to reason about others, andfurther it has the similar form and role to modus ponens and (K) axiom of knowl-edge logic. The relationship between speech acts and common sense is also discussedwhich is necessary for RAO. Based on ideas from situation calculus, this relationshipis characterized by an axiom schema in RAO. Our theories are also demonstrated byan example.

Multiple Choice Items in Testing

Language testing is very important and necessary,and moreover as we all know,nowadays,in English language testing, the muhiple-choice item is most widely used and many users regard the multiple-choice item as the most flexible and probably the most effective of the objective item types.The multiple-choice item has its characteristics,advantages and disadvantages.We should bring out its strengths to make up for its weaknesses and use it appropriately.Although it has its limitations,it is suitable for large-scale tests and tests dealing with wide-range knowledge.We should correctly ap- ply testing principles and methods in order to make testing more effective and reliable.

Anti-Monopoly Regulation of Digital Platforms

Characterized as they are by dynamic competition,cross-border operation,the network effect and oligopoly competition,digital platforms present a serious and complex monopoly problem,one that undermines competition,damages consumers’ interests,suppresses the vitality of innovation and hinders high-quality development.They should therefore be brought under stricter anti-monopoly regulation.The traditional regulatory cycle of “stricter regulation brings everything to a standstill;looser regulation brings chaos in its wake” is a chronic problem in China’s market regulation,so the anti-monopoly regulation of digital platforms needs to avoid this regulatory paradox.To address digital platforms’ two-sided markets,dynamic competition and disruptive innovation,we need to create appropriate new theories of anti-monopoly regulation by establishing the principle of positive,inclusive and prudent regulation based on the concept of modesty.In the current context,efforts to strengthen regulation do not lay undue emphasis on tighter regulation and heavier penalties,but rather focus on regulatory transformation and innovation,aiming thereby to effectively improve regulation.Good law is the premise of good governance.It is necessary to speed up the revision of the Anti-Monopoly Law to include provisions for improving digital competition rules in order to provide high-quality regulatory systems.Actively promoting efficient,inclusive and prudent regulation,fair and impartial regulation,collaborative and integrated regulation,incentive-based regulation,credit regulation and intelligent regulation on the basis of good law,along with technology-enabled regulation,is a good governance approach to realizing anti-monopoly platform regulations.

THE SYMMETRIC POSITIVE SOLUTIONS OF 2n-ORDER BOUNDARY VALUE PROBLEMS ON TIME SCALES

In this paper, we are concerned with the symmetric positive solutions of a 2n-order boundary value problems on time scales. By using induction principle,the symmetric form of the Green＇s function is established. In order to construct a necessary and sufficient condition for the existence result, the method of iterative technique will be used. As an application, an example is given to illustrate our main result.