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The steady and reliable operation of a ship's diesel engine is important to the ship's electrical power system and the engine's performance, and stable control of rotational speed is crucial to a diesel engine's emission, economy and power performance. A ship's diesel engine is a nonlinear and timevarying system. A traditional proportional-integral-derivative (PID) controller cannot regulate the speed under different working conditions. In this paper, a nonlinear mathematical model for speed regulation of diesel engines is established according to experiments and a multi-sliding surface variable structure controller for speed regulation of diesel engine is established by sliding mode control. A bulk cargo ship 500-I was analysed as an example. The MATLAB/Simulink simulation took the navigation environment and the effect of the ship propeller on the diesel engine into consideration. A simulation model considering the whole ship-engine-propeller system is built and some conclusions can be drawn from the simulation. The multi-sliding surface control can restrain the overshoot and realize a quick track of the targeted value with high accuracy and strong robustness. In addition, the fuel consumption and CO 2 emission of this sliding mode variable structure control is reduced by 4.6% compared with traditional PID control.

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This paper addresses the operational decisions and coordination of the supply chain in the presence of risk aversion, where the risk averse retailer’s performance is measured by a combination of the expected profit and conditional value-at-risk (CVaR). Such performance measure reflects the desire of the retailer to maximize the expected profit on one hand and to control the downside risk of the profit on the other hand. The impact of risk aversion on the supply chain’s decision and performance is also explored. To overcome the inefficiency due to the double marginalization and the aggravation resulting from risk aversion, we investigate the buy-back contract to coordinate the supply chain. Such contract can largely increase the supply chain’s profit, especially when the retailer is more risk averse. Lastly, we extend such risk measure to the widely-used business model nowadays — platform selling model, and explore the impact of the allocation rule on the manufacturer’s decision.