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This article reviews the operations management (OM) research on service outsourcing, a common practice among current businesses. We focus on recent literature in three areas: capacity planning and supplier coordination, service outsourcing under information asymmetry, and quality concerns. Additionally, a mathematical framework is presented that can be used to analyze service outsourcing supply chains. We conclude with discussions on some promising future research areas.

The rheological regulation of the "three high" (high temperature, high density and high salinity) waterbased drilling fluid is a worldwide problem due to the combined influence of temperature, solid content and salinity. This paper investigates the factors and regulation methods about rheological property of "three high" water based drilling fluid, and the effects of clay, salinity and weighting materials on the drilling fluid rheology. The experimental results show that base mud compound bentonite with attapulgite had good salt resistance and temperature resistance. The clay content should be kept close to 2% in high density mud (ρ=2.0g/cm 3), to control drilling fluid rheology. The sequence of rheological parameters of the "three high" water-based drilling fluid with same density was: manganese oxide> micronized barite> barite> ilmenite powder. When barite compounded with ilmenite powder or micronized barite in the ratio of 1:1 to weight drilling fluid respectively, the rheology and filtration of the "three high" water-based drilling fluid performed well. Based on the optimization of a series of mud additives including fluid loss additive, thinner, anti-collapse filtration reducing agent, lubricant with salt and calcium resistance, a formula of the "three high"water-based drilling fluid system was prepared which had excellent rheology, filtration and sedimentation stability property with the density of 2.2g/cm 3 (180℃). The expansion rate of the drilling fluid was 1.84%, shale recovery rate was 85.73%, lubrication coefficient was 0.122, and resistanced to pollution of 1% CaCl2 and 10% poor clay. It also had excellent reservoir protection and plugging performance.

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A new algorithm is proposed for the optimization of grasping torques. Previous work revealed that the optimization of the contact force can be simplified as a linear programming problem by replacing the nonlinear friction cone with a polyhedral cone. On this basis, further simplification and linearization is completed for various grasp contact constraints of the grasping system, and an optimization model is established with the minimum sum-of-squares of joint torques as an objective function. A timely and effective algorithm based on key constraint sets is then established. This methodology optimizes the joint torque directly and facilitates the control of the dexterous hand. A numerical example and experimental results show that the optimization algorithm has high precision and good real-time performance. The joint torque output obtained using the proposed algorithm was 27.6% lower than the result of the previous algorithm. The optimization algorithm can thus be used for optimal grasping control of a dexterous hand.