Shuhong Zhang and Mianyun Chen
The system with partial unknown structure, parameters and characteristics is called a grey system. Grey system theory is a newly developed theory to deal with the problem of…
Abstract
The system with partial unknown structure, parameters and characteristics is called a grey system. Grey system theory is a newly developed theory to deal with the problem of uncertainties in the case with “poor” information and has widely been used in many fields. The grey prediction SCGM(1,1) model has been used widely. In this paper, the characteristics of SCGM(1,1) model are systematically studied. Some new existing forms of SCGM(1,1) are derived including exponential form, α, β parameter form, scale form and recursive form. The parameter range suitable for SCGM(1,1) modeling has been studied based on strict proof. The prohibited area and the area not suitable or suitable for modeling of SCGM(1,1) model are divided clearly according to the developing coefficient a. Then, the discrete form of developing coefficient a is given. Based on the discrete form of developing coefficient a, a new grey modeling method avoiding complex matrix calculation is presented.
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Yongbing Chen, Yexin Song and Mianyun Chen
The purpose of this paper is to identify the Nomoto ship model parameters accurately, in order to produce a very close match between the predictions based on the model and the…
Abstract
Purpose
The purpose of this paper is to identify the Nomoto ship model parameters accurately, in order to produce a very close match between the predictions based on the model and the full‐scale trials.
Design/methodology/approach
Various ship maneuvering mathematical models have been used when describing the ship dynamics behavior. The Nomoto ship model is a class of simplified hydrodynamic derivative type models which are the most widely used, accepted and perhaps well developed. To determine the model parameters accurately, particle swarm optimization (PSO) is chosen as an evolution algorithm in this paper. This arithmetic can guarantee the convergence and global optimization ability, and avoid sinking into a local optimal solution.
Findings
The process of PSO for identifying the Nomoto ship model parameters is given.
Research limitations/implications
Availability of the full‐scale trial data are the main limitations.
Practical implications
The ship model parameters provide very useful advice in ship's autopilot process.
Originality/value
The paper presents a new parameter identification method for the second‐order Nomoto ship model based on PSO.
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Van‐Tsai Liu, Chien‐Hung Liu, Hau‐Wei Li, Chieh‐Li Chen, Chun‐Liang Lin and Yu‐Chen Lin
The purpose of this paper is to develop the multi‐degree‐of‐freedom measurement system to test, verify, and control the nano‐measuring machine.
Abstract
Purpose
The purpose of this paper is to develop the multi‐degree‐of‐freedom measurement system to test, verify, and control the nano‐measuring machine.
Design/methodology/approach
A generic differential model approach is constructed to numerically describe the hysteresis effects of piezoelectric actuators. Based on the generic differential model, a feedforward compensator with a proportional integral (PI) type controller is designed to compensate for the hysteresis nonlinearity of a piezoelectric actuated three degree‐of‐freedom coplanar nanostage which can provide high‐precision applications.
Findings
The Z‐tilts (z, pitch, and roll motion) error compensation stage of the nano‐measuring machine is accomplished. Moreover, a high‐resolution laser interferometer is used to measure position accurately.
Originality/value
This paper contributes to develop a tracking control design method for the piezoelectric motion platform which combines a closed‐loop feedforward compensator with a PI type controller.
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Shulin Liu, Rui Ma, Rui Cong, Hui Wang and Haifeng Zhao
Embedding dimension determination in phase space reconstruction is difficult. The purpose of this paper is to present a new approach for embedding dimension determination based on…
Abstract
Purpose
Embedding dimension determination in phase space reconstruction is difficult. The purpose of this paper is to present a new approach for embedding dimension determination based on empirical mode, showing that embedding dimensions for phase space reconstruction could be easily determined according to the number of intrinsic mode functions decomposed by empirical mode decomposition.
Design/methodology/approach
Through the relation analysis of intrinsic mode functions and embedding dimensions, the approach for embedding dimension determination by the number of intrinsic mode functions is presented. First, a time series is decomposed into several intrinsic mode functions. Second, correlation analysis between intrinsic mode functions and original signals is investigated, and then false intrinsic mode functions could be eliminated by the analysis of correlation coefficient thresholds, which makes the embedding dimension precise. Finally, the method presented is applied to the Lorenz system, Chen's system, and the Duffing equation. Simulation results prove this method is feasible.
Findings
A new approach for embedding dimension determination based on empirical mode decomposition is presented. Compared with G‐P algorithms, this new method is effective and decreases computational complexity.
Research limitations/implications
This method provides an effective qualitative criterion to the selection of embedding dimensions in phase space reconstruction.
Practical implications
This method could be used to determine embedding dimensions of phase space reconstruction and degree‐of‐freedom of nonlinear dynamical systems.
Originality/value
The paper proposes a new method of embedding dimension determination in phase space reconstruction.
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Zhijie Chen, Weizhen Chen and Qile Chen
The purpose of this paper is to propose a new group decision‐making approach, which can only use simple mathematical calculations to perform a group decision‐making task.
Abstract
Purpose
The purpose of this paper is to propose a new group decision‐making approach, which can only use simple mathematical calculations to perform a group decision‐making task.
Design/methodology/approach
The large column and large row (LCLR) method is designed and applied.
Findings
The paper finds four propositions to support LCLR methods to be a simple and effectual means for group decision making.
Research limitations/implications
The aggregated matrix constructed in LCLR methods should be generated from non‐contradictory circles.
Practical implications
Effective group decision‐making results can be obtained by easily used methods, not necessarily by using complex mathematics technology to conduct the task.
Originality/value
The new approach based on LCLR methods proposed in this paper may be one of the most easily used and effective means for group decision making.
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Tong Xiaojun, Chen Mianyun and Li Zhijun
Based on ideal absolute errors and relative errors, a new grey model‐GMp(1,1) model is presented. The existence problem of its solution is also solved based on a few conditions…
Abstract
Based on ideal absolute errors and relative errors, a new grey model‐GMp(1,1) model is presented. The existence problem of its solution is also solved based on a few conditions. Then, MGMp(1,n) model is presented. These optimized models GMp(1,n) and MGMp(1,n) have good anti‐noise property to absolute and relative errors. Examples illustrate that they have very good fitting and forecasting results.
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Dejun Chen, Zude Zhou, Yingzhe Ma and D.T. Pham
The purpose of this paper is to create a platform framework based on agent for virtual enterprise (VE) with the characteristic of supply chain by adopting multi‐agent technology.
Abstract
Purpose
The purpose of this paper is to create a platform framework based on agent for virtual enterprise (VE) with the characteristic of supply chain by adopting multi‐agent technology.
Design/methodology/approach
According to the system hierarchy theory and the features of VE with the characteristic of supply chain, the conception and organization structure of supply chain‐oriented VE are proposed. Combined with characters of multi‐agent, a platform framework based on agent for VE with the characteristic of supply chain is created. Aiming at complexity of net node of running platform framework, two‐layer architecture mode, which are information alternation layer and basic function layer inside net node based on agent, are designed. The modes are proved to be reasonable in the management of the system and networks resources.
Findings
The theory base of realization of the VE based on agent with the characteristic of supply chain is found.
Research limitations/implications
The reasonable basic function design of various agents are main limitations.
Practical implications
The paper presents a very useful tool for the operation and management of VE.
Originality/value
A new approach and scheme for VE with the characteristic of supply chain is presented. This paper is aimed at researchers and engineers.
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Jiang Guo, Yajin Liu, Xianglian Xu and Qijuan Chen
The purpose of this paper is to obtain the characteristic parameters of dynamic trend for hydro turbine governors, and take these as the inputs of the neural network to realize…
Abstract
Purpose
The purpose of this paper is to obtain the characteristic parameters of dynamic trend for hydro turbine governors, and take these as the inputs of the neural network to realize the diagnosis of the system.
Design/methodology/approach
Computer simulation technique has become an important tool in the science research and development. Because of the different degree defaults of the traditional modeling method, a distributed bond graph modeling (BGD) method is presented in this paper. Fault diagnosis and identification have been widely developed in recent years, while many kinds of diagnosis methods have been used in this area. Since it is difficult to get the characteristic parameters of dynamic trend, a new methodology is proposed which integrates BGD and neural network. It gets the characteristic parameters by simulation to the system, and takes these as the inputs of the neural network to realize the diagnosis of the system.
Findings
The paper presents the need for application of two models – conventional procedure and bond graph model approaches.
Practical implications
The paper is a very useful diagnosis tool for operators.
Originality/value
A new methodology is proposed which integrates BGD and neural network. The paper is aimed at operational researches and engineers, the results from simulations are reported and commented in the paper.
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The purpose of this paper is to study the relationship of broad‐spectrum analysis and pansystems methodology from the fundamental questions of the study of broad‐spectrum analysis.
Abstract
Purpose
The purpose of this paper is to study the relationship of broad‐spectrum analysis and pansystems methodology from the fundamental questions of the study of broad‐spectrum analysis.
Design/methodology/approach
By means of structure analysis and comparison method, the paper gives an introduction to the inner features and connections of broad‐spectrum analysis and pansystems methodology, respectively.
Findings
The opinion that pansystems methodology applies in the two features of broad‐spectrum analysis is put forward, and three aspects in the application of broad‐spectrum analysis in pansystems methodology are analyzed.
Research limitations/implications
The details of the structural models in this paper have to be worked out.
Practical implications
The paper contributes to understanding the features of broad‐spectrum analysis and pansystems methodology.
Originality/value
The paper reveals the original relationship between broad‐spectrum analysis and pansystems methodology, which embodies the value of pansystems methodology to broad‐spectrum analysis.