According to the technological requirements of float disc brake caliper during processing, special fixture of the caliper is researched based on 3D design in this paper. Through the design and kinematics simulation for special fixture 3D model, it is convenient to forecast assembly interference of lathe fixture and add the mass of lead brick accurately before prototype is made. Therefore, it solves the vibration problem of special fixture due to the unbalance mass and improves the run-out tolerance precision of cylinder hole of the workpiece compared with machine tool spindle. These means ensure the processing quality of the cylinder hole in brake caliper.
Using the established evaluation indicator system of province-territory logistics development, we adopted the non-linear principal component analysis method to carry on the appraisal of the present situation of logistics service system in Heilongjiang Province, analyzed the level of logistics service system in different areas quantitatively. Then we proposed the Heilongjiang Province-territory logistics development can be divided into Ha-Da-Qi, Ha-Mu-Sui and Jiamusi urban cluster as the three main logistics regions. At last, we formulated corresponding development strategy according to their different characteristics.
PID control is used widely in hydraulic servo control system. The PID control parameters are very important to performance of hydraulic servo control system and how to find rapidly the optimum values of PID control parameters is very difficult problem. Based on Matlab/simulink software and taking the IATE standards of the optimization design as objective function, a global search optimization method, called Evolutionary Cellular Automata Algorithm which has a digging operator and two learning operators (dual arithmetic crossover operator and chaos-peak-jumping operator) was applied for the optimization of the three parameters of PID controller of electric-hydraulic servo system of 6-DOF parallel platform. Simulation results show that the proposed parameter optimum method is an effective tuning strategy and has good performance.
We considered the single machine scheduling with fixed delivery dates and temporary storage. The objective is to minimize the sum of the makespan and the total inventory costs. We showed that the problem is strongly NP-hard and polynomial-time approximation algorithm with a fixed performance ratio does not exist for the problem unless P=NP. A polynomial 3/2-approximation algorithm for the case with period delivery times was presented and the performance ratio of 3/2 can not be improved unless P=NP.
Supplier selection is a multi-criteria problem including various factors. It is increasingly becoming a strategic issue for companies in supply chains and it is usually made by multiple decision makers according to multiple criteria. Vendor selection has an important impact on the competitiveness of firms. Considering to its complexity, the work will focus especially on the final selection stage with the method of fuzzy-ANP. We use ANP when considering the feedback and the relations between those factors. Due to complexity in assessing supplier selection performance, it is difficult for decision-makers to provide exact numerical values for the factors. Therefore, a fuzzy ANP method was taken to calculate the weights of each factor of the model, which can solve problems in an uncertain condition effectively.
In recent years, the situation of food safety has been better than before in our country, but we are still facing severe challenge as there are often food safety issues in circulation field, so strengthening food safety management in circulation is the keystone in food safety work in China. 2008 Olympic Games in Beijing and 2010 World Expo in Shanghai will further promote economic development, in which food safety is very important. There is much food safety experience and measures to ensure food circulation safety abroad well worthy of our learning. HACCP Certification System is generally applied in the world and is helpful to strengthen food safety in the circulation of our country. Through analysis of factors causing food safety hazards, this thesis puts forward the existing food safety issues in the circulation field of our nation and focuses on research how HACCP enhances the safety of food circulation.
The present study on product service system (PSS) paid little attention to strategic lifecycle perspective, herein lost strategic sustainable for PSS, firms and service supply chains (SSC). To improve it, this paper critically reviewed the study on PSS, firm, and SSC etc. with strategic and tactical lifecycle perspective. Based on this review, it redefined PSS and put forward an evolution framework of PSS for firms across SSC with integrated lifecycle perspective. This framework might give a new approach on the evolution mechanism of PSS for firms across SSC.
The regional logistics industry is a very important mainstay industry of the regional economy, and it has an huge effect upon the regional economy development. According to the characteristics of region logistics system, the synergetic development significations of region logistics system are analyzed, and the synergetic development mechanism of regional logistics system is put forward based on the region economy convergency theory in order to effectively adjusting the regional logistics industry structure and accelerating the synergetic evolution of regional logistics system. Moreover, the synergy relation degree model between region logistics system and regional economy is built to find out the order parameter and development rules of region logistics system and guide the regional industry adjustment and economy development.
Motivated by increased use in practice and increased interest in the media and among academics, a performance evaluation system was built based on Economic Value Added (EVA) and Balanced Scorecard (BSC) for logistics enterprises. Correlation test and linear regression were run to give empirical support for the system. Leading the long-term vision, EVA is at the top of this system. Other measures distributed in four perspectives - Financial, Customer, Internal business process and Learning and growth - are aimed to a high EVA. EVA gets significantly positive Kendall's correlation with strategic objective whose proxy is corporate value. In linear regression whose dependent was EVA, operation cost, the first five customers' revenue ratio, audited internal control report and staff educational ratio were used to represent the four perspectives respectively. The first and the third measures have significant coefficients consistent with theoretic analysis.
The aim of this paper is to study a mixed integer nonlinear programming model including forward logistics and reverse logistics. The problem is how to select plants, stores and collection points to constitute a closed-loop network, and how to expend the chosen plants, stores and collection points. Differential evolution algorithm is applied to solve the problem. The differential evolution algorithm originally is for global optimization over continuous spaces. According to the characteristics of the model, mapping method is developed to handle discrete variables. This study offers the improved differential evolution algorithm that optimizes the forward and reverse logistics simultaneously. Result shows the algorithm has a rapid convergence rate.
As grocery shopping shifted from traditional to online environment, consumer logistics that shoppers once completed by themselves has been undertaken by E-Grocers(Online Grocers). Consequently the principal-agent relationship is built between online shoppers and E-Grocers due to the information asymmetry. The Principal-Agent Problem in this context was identified and explained by using the principal-agent theory and a mathematical model was constructed. The results indicate that, when the surplus benefit is nearly dependent on online shoppers completely, e-grocers will make effort to reduce logistics cost, improve logistics services and avoid the moral hazard on the conditions of building a thorough evaluating system for the service quality of consumer logistics and an effective incentive mechanism, redesigning a coordination mechanism and cultivating an e-grocery shopping market with the development of online grocery shopping market and consumer logistics outsourcing market.
Knowledge sharing can make organizational knowledge freely flow in definite range to benefit for knowledge application and innovation. But employees don't share their knowledge actively. The purpose of this paper is designing effective incentive mechanism of employee knowledge sharing on the basic of comprehensive management pattern to implement knowledge sharing. Through applying principal-agent theory and mathematical analysis method, optimal incentive mechanism of employee knowledge sharing was designed, then four conductive significant properties were analyzed. The results show that the important influencial factors on employee knowledge sharing are reward incentive and management incentive of enterprise, sharing cost and psychological sensitive coefficient of employee, investment intensity and operation efficiency of management system. The paper supplies theoretical basis and practical guide to promote staff knowledge sharing for enterprise manager.
The purpose of studying coordinated development degree of supply and demand is to measure the operational compatibility of city distribution system. A model of coordinated development degree of supply and demand is developed with coordinate factors and development factors. Two aspects of supply and demand are considered in the process of designing the model and index system. Empirical sample data is collected from supply and demand of city distribution in Beijing and Shanghai to verify the validity of the model. Key index defining coordinated development degree of supply and demand is concluded and the improvement measures are proposed correspondingly.
It is difficult to have good performance to control large delay time system. A neural network identification method for nonlinear system's delay time was discussed. Using the abrupt mutation resulted from the training error sum square of the real output and the expected output of the network, this method changed the input sample period of the neural network so that it could discriminate the delay time of the nonlinear model. Combining the discrimination of neural network system with long time delay and the control method based on model prediction, searching PID controller parameters based on ant colony optimization algorithm, it was applied to control boiler combustion system. The simulation results show that this scheme has much better advantage of celerity and robustness.
3G Era, it is the great strategic significance for operators and service providers to establish a solid cooperation to improve the competitiveness of the mobile service chain. To explore the contract mechanism between the operators and service providers, this paper studied the operation model of the major operators and providers in the Zhejiang Province, analyzed the existing models of cooperation, based on the supply chain contract mechanism, proposed the multi-contract mechanism, tried to coordinate the supply chain system, builded a supply chain model based on the service, analysed the profit function, combined actual case analysis, and drawn the conclusion that the multi-contract based business can enhance the competitiveness of the mobile services supply chain.
The simple trust evaluation methods that result in a final trust level (FTL) value can't be able to evaluate service trust trend (STT). Furthermore, statistical trust values include some unfair and questionable trust values caused by subjective or objective factors. In response to these problems in trust management, an approach called two-way trust evaluation based on feedback is presented. This approach adopted the fitting a-ary quadratic trend curve to evaluate STT. According to the fitting a-ary quadratic trend curve, replace unfair and questionable trust values with STT expectations. Meanwhile, send feedbacks for these clients who sent unfair and questionable trust values to the trust management system and realize two-way trust evaluation based on these feedbacks. Experimental data show that this approach is able to evaluate STT, lessen the trust evaluation errors and enhance the fairness and rationality of trust evaluation.
This paper considers the problem associated with the stability analysis and stabilization for singular systems with multiple time-varying delays. The delay-dependent stability criterion and the method of designing state feedback stabilization controller are obtained by using Lyapunov second method and LMI techniques. Numerical examples illustrate the efficiency and feasibility of our method.
