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Recent years have witnessed substantial research efforts on computation offloading for mobile edge computing (MEC) systems. User mobility is an intrinsic trait of many MEC applications, which has posed significant challenges for realizing reliable computing. However, existing works studying this problem mainly focus on the movements of users while another high-dynamic behavior due to the randomness of computation task is largely ignored. To fill this gap, in this paper, we formulate the computation offloading decision problem in MEC system as a combinatorial optimization problem, and then we use Log-Sum-Exp function to approximate the optimal objective. Thereafter, we construct a Markov chain with steady-state distribution specifying to our problem in a distributed manner, such that the user mobility problem is transformed into the state transition problem. Moreover, this Markov chain is further extended to consider a dynamic scenario where the number of active users in the MEC system changes due to the random arrivals of new computation task or completions of old tasks. Numerical results show that our proposed computation offloading distributed algorithm can converge very fast to the optimal solution, and has a provable performance with a guaranteed loss bound. [ABSTRACT FROM AUTHOR]

Background/Aims: Somatostatin is regarded as a prophylactic agent on post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis (PEP), but studies are still controversial. Materials and Methods: Electronic databases, including PubMed, EMBASE, the Cochrane library, and the Science Citation Index, were searched to retrieve relevant trials. In addition, meeting abstracts and the reference lists of retrieved articles were reviewed for further relevant studies. Results: Eleven randomized controlled trials (RCTs), enrolling a total of 2869 patients, were included in the meta-analysis. After data were pooled from somatostatin trials, PEP occurred in 8.36% of controls versus 5.62% of the treated group, with a slight significance [relative risk (RR) =0.58, 95% confidence interval (CI) 0.35-0.98, P = 0.04]. The funnel plot showed no asymmetry with a negative slope (P Themeta= 0.108). The -analysis produced negative results for short-term infusion of somatostatin (RR = 1.40, 95% CI 0.93-2.12, P = 0.11), whereas a bolus or long-term injection of the drug proved effective (RR = 0.25,95% CI 0.13-0.47, P < 0.0001; RR = 0.44,95% CI 0.27-0.71, P = 0.0008). Postprocedure hyperamylasemia and pain was also observed in the meta=0.0008).-analysis, the pooled RR was significant for reduced risk of postprocedure hyperamylasemia (RR = 0.72, 95% CI 0.63 to 0.81, P < 0.00001), but not for the pain<0.00001), (RR = 0.67, 95% CI 0.42 to 1.08, P = 0.10). Conclusion: The current meta-analysis on the prophylactic use of somatostatin in patients undergoing ERCP documents a lack of benefit when given as short-term infusion, but showed an advantage of a single bolus or long-term injection. The beneficial effect of somatostatin, in reducing the incidence of postprocedural hyperamylasemia seems of marginal clinical significance. However, more new confirmatory data are needed to settle residual doubts. [ABSTRACT FROM AUTHOR]

By comparing simulations with experiment, we show that the effective refractive index of fused SiO2 can be locally reduced by (1.8 +- 0.2)% by femtosecond laser nanostructuring. We create a microlens of material containing a planar array of nanocracks embedded inside fused silica and probe how it refracts or absorbs light as a function of pulse energy. The self-generated microlens lowers the peak light intensity by deflecting the light around the focus. We obtain the refractive index by simulating the beam transport using the 3D wave equation in conjunction with the measured dimensions of the modified material. [ABSTRACT FROM AUTHOR]