Dan Ling

Hierarchical Colored Petri Nets based components for workflow systems

Workflow systems have benefited the enterprise and customer in many aspects. But with the increasing complexity of the system, workflow design becomes a complicated and time-consuming process. In this paper, we model the system based on the Hierarchical Colored Petri Nets (HCPN) to avoid the complexity of the system, and the super nets of the model are abstracted as independent components to increase the flexibility, acceptability and maintainability of the system. Another important characteristic of this model is its convenience for reuse and workflow mining. The development process of the overhead traveling crane was given to demonstrate the proposed method.

New hybrid real-coded genetic algorithm

Real-coded Genetic Algorithms (RGAs) usually meet the demand of continuous and continuous/discreet mixed space problems and have been widely applied in many fields. The paper proposed a new Hybrid Real-coded Genetic Algorithm (NHRGA), in which the idea of Particle Swarm Optimization (PSO) is introduced into mutation operator and physics field theory is also employed in algorithm operators. The NHRGA reduces the possibility of trapping into the local optimal solutions and improves the computation efficiency. A practical engineering example is given to demonstrate computation efficiency and robustness of the proposed method.

Equipment reliability analysis based on the Mean-rank method of two-parameter Weibull distribution

Weibull distribution is a continuous probability distribution model and it has been widely used in reliability engineering. When we use Least-squares method to estimate the parameters of Weibull distribution, the empirical distribution function of life model is a key factor in accuracy. Typically to some complex mechanical products in the life test of reliability, the test sample is incomplete because of the test time, conditions, cost and other factors. If we directly use the approximate Median-rank formula to calculate the equation, it will cause large errors. In this paper, we use the Mean-rank method to calculate the equation. According to the Mean-rank method increment formula by statisticians, we can insert it into approximate Median-rank formula to get the sample empirical distribution. This method can improve the precision of parameter estimation.

Reliability analysis of distribution system based on the minimum cut-set method

As the end point of power delivery, a distribution system is directly connected with the consumers. It has complex structures and various operation modes which make the reliability even more important. However, the traditional FMEA cannot be applied to the complex distribution system which contains ring networks. Taking the capacity constraint of distribution system into consideration, this paper analyzes the reliability of IEEE DRTS system with FMEA based on the minimum cut set.

Curve fitting with weight assignment under evidence theory combination rule

In engineering practices, curve fitting is a common method to evaluate the performance of machines or equipments using the collected data. If the collected data works as a whole and can not be divided into groups, conventional curve fitting methods can be used to perform the task. Researchers have proposed some improved methods with higher precision and computational efficiency, in order to handle some special situations. Another special situation, however, involves the collected data that consist of more than one sample set, which show obvious differences in collection methods, collection districts and other aspects one could meet. If we treat this collected data as one set, the information reflecting the differences may be ignored and lost in the curve fitting procedure. D-S evidence theory is a widely used method to solve multiple-source uncertain and imprecise information fusion. In this paper, the evidence theory combination rule is introduced to curve fitting preprocessing for weight factor assignment according to the fusion result, so as to address this special situation.

Reliability assessment of ring-standby structure based on monte carlo simulation

Ring-standby is a type of structure that has been used in complex systems with high reliability requirement. This paper presents a Monte Carlo based reliability evaluation method for this type of structure. The analysis results obtained from this method are compared with those from Markov and Dynamic Fault Tree (DFT) approaches. It is shown that the Monte Carlo simulation can yield additional useful information on the complex ring-standby structure.

Study for Public Transport Vehicle Location and Navigation System Based on GPRS

Based on analysis requirement of function for public transport vehicle location and navigation system, and the characteristic of General Packet Radio Service (GPRS), the method of making up public transport vehicle location and navigation system using GPRS communications platform is studied. The system architecture for public transport vehicle location and navigation system based on GPRS is put forward. The system composition and function is described

Notice of Retraction Fatigue life assessment of welded structures by effective notch stress approach

This paper is concerned with the calculation of stress in the region of interest in complex welded structures. However, analysis of welded structures still remains a challenge for the analyst and in fact cannot be considered as fully resolved for practical applications. The purpose of this paper is to provide some discussion on selected methods recommended by International Institute of Welding (IIW). Then a practical example of boogie frame is presented to illustrate the effective notch stress method and the concept of submodel.

A Method for Multiaxial Fatigue Reliability Analysis Based on Mixed Weibull Distribution

The fatigue life of mechanical element is a random variable in nature following some kind of statistical distribution.In this paper, a method for reliability life prediction considering life randomness is proposed. Firstly, the Smith-Watson-Topper (SWT) model is used to describe the relationship of the maximum normal stress and strain range on the critical plane. Secondly, the maximum normal stress and strain range on the critical plane are calculated by finite element analysis. Thirdly, fatigue life samples are generated using Monte Carlo simulation method, and the mixed Weibull distribution is used to model the distribution of fatigue life of turbine discs. Finally, the proposed method is validated by comparing the prediction results from the proposed method, the observed cumulative failure probability based on median rank, and the standard two-parameter Weibull distribution.Copyright

Concurrent Engineering Based Collaborative Design Under Network Environment

Concurrent Engineering (CE) is a popular method employed in product development. It treats the whole product design process by the consideration of product quality, cost, rate of progress, and demands of customers. The development of computer and network technologies provides a strong support to the realization of CE in practice. Aiming at the characteristics of CE and network collaborative design, this paper built network collaborative design system frame. Through the analysis of the network collaborative design modes based on CE, this paper provided a novel network collaborative design integration model. This model can integrate the product design information, design process, and knowledge. Intelligent collaboration was considered in the proposed model. The study showed that the proposed model considered main factors such as information, knowledge, and design process in collaborative design. It has potential application in CE fields.