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For many optimization problems such as optimal techniques, compositions, producing process, the optimizing objectives in systems are complex relations with respect to a great deal of parameters. Generally, the objective function is hardly obtained, even the searching objective is unquantifiable. So it is difficult to model and optimize the complex systems to some extent.

To the above purpose, a novel approach is presented in this paper. It firstly utilizes the excellent fitting performance of neural network (NN) combined with expert knowledge (EK) to obtain the objective function, and secondly searches the optimal influential parameters with genetic algorithm (GA).

Peaks function inside Matlab and the acural application of comprehensive performance optimization in analog PID control system are studied, respectively. The results of simulation and the actual experiment both show that the modeling and optimizing method presented in the paper are effective.

Expert knowledge is needed for the fuzzy/unquantifiable objective.

The paper presents a useful way to model and optimize complex systems.

The combined approach based on NN, EK and GA is firstly presented and is effectively used in modeling and optimizing complex systems.

The purpose of this paper is to present a novel dynamometer employing direct torque control (DTC) method, which has wide application prospects in the industry field.

Conventional dynamometers such as eddy dynamometers waste energy, waste water, and operate inconveniently. In this paper, a novel digital electric power dynamometer is proposed which uses a three‐phase squirrel‐cage induction machine as the loading machine. The system uses a digital signal processor named TMS320LF2407A as the controller to control the three‐phase induction machine employing an improved DTC for precise torque tracking. The power dynamometer is in generating mode, using the common‐DC‐bus to implement energy circulating or through the energy regenerating unit feeding back the networks energy. A direct‐torque‐controller dynamometer allows very fast torque responses and flexible control. The load torque is regulated conveniently and swiftly.

Simulations and experiment results show that the design of the electronic power dynamometer based on improved DTC is proper, the control is simple, and digitized and is simple to use.

The precise torque controls are the main limitations for the high‐performance power dynamometer applied. Torque ripples should be small.

Power dynamometer based on DTC is one of the novel ones worth being generalized in place of conventional dynamometers.

The new approach of a novel digital power dynamometer based on an improved DTC is introduced.

Purpose – To provide marketing and managerial insights to western companies selling denim jeans in China, specifically in Shanghai. Understanding consumers' perceptions of Western‐branded jeans in a cultural‐specific marketplace is the primary focus. Design/methodology/approach – Combined methods included observation of shoppers wearing jeans in two malls in Shanghai and an anonymous survey. A total of 219 surveys were analyzed and consumer‐perceived jeans attributes or related concepts were tabulated. Findings – About one third of the observed shoppers were wearing jeans, which signified a relatively high popularity of jeans as casual wear in Shanghai. The design and fashion of jeans were deemed highly critical but were superseded by comfort and fit. Shanghai consumers distinguished brand origins only between the West and the East instead of by specific countries. Dissatisfaction with price and fit were identified. Research limitations/implications – Questions were designed to screen out respondents who had not purchased and had no desire to purchase western denim jeans brands. Limiting the sample in this way offered some control for behavioral patterns, but conclusions are limited. Practical implications – Content analysis of an open‐ended question about consumers' perceptions of western‐branded jeans helped discern attributes of jeans that consumers deemed most important. Marketers of western jeans can develop effective marketing strategies in tune with consumer preferences. Originality/value – This paper researched consumers' perceptions of western denim jeans, a type of world dress, in a booming but foreign market in western eyes. The open‐ended question solicited consumers' free responses, which in turn helped pin‐point attributes of jeans that Chinese consumers value the most.