Zhejiang Gongshang University

Abstract: As cloud-based services become more numerous and dynamic, resource provisioning becomes more and more challenging. A QoS constrained resource allocation problem is considered in this paper, in which service demanders intend to solve sophisticated parallel computing problem by requesting the usage of resources across a cloud-based network, and a cost of each computational service depends on the amount of computation. Game theory is used to solve the problem of resource allocation. A practical approximated solution with the following two steps is proposed. First, each participant solves its optimal problem independently, without consideration of the multiplexing of resource assignments. A Binary Integer Programming method is proposed to solve the independent optimization. Second, an evolutionary mechanism is designed, which changes multiplexed strategies of the initial optimal solutions of different participants with minimizing their efficiency losses. The algorithms in the evolutionary mechanism take both optimization and fairness into account. It is demonstrated that Nash equilibrium always exists if the resource allocation game has feasible solutions.

Abstract: With increasing demand for environment friendly aquaculture, the use of probiotics in aquaculture is now widely accepted. However, there is clearly a need in increasing our knowledge of intestinal microbiology and of effective preparation and safety evaluation of probiotics. This review provides a summary of the status and challenges of probiotic application in aquaculture. Our review is from the perspective of digestive tract, thereby taking into account the experiences in introducing the preparation, use and safety evaluation of probiotics in aquaculture. A better understanding of rationale, preparation and safety of probiotics in aquaculture may be of interest for commercial aquaculture.

Abstract: Food waste anaerobic fermentation was carried out under acidic conditions using inocula based on aerobic activated sludge (Inoculum AE) or anaerobic activated sludge (Inoculum AN) for volatile fatty acids (VFAs) production. The results showed that food waste hydrolysis increased obviously when Inoculum AN was used relative to Inoculum AE at any pH investigated. Hydrolysis at pH 4.0 and uncontrolled pH was higher than that at other pHs when either inoculum was used. Additionally, VFAs production at pH 6.0 was the highest, regardless of the inoculum used. The optimum VFA yields were 0.482 g/g VSS removal with Inoculum AE and 0.918 g/g VSS removal with Inoculum AN, which were observed after 4 d and 20 d of fermentation, respectively. VFAs composition analysis showed that butyrate acid was the prevalent acid at pH 6.0, followed by acetate acid and propionic acid.

Abstract: The effect of probiotics on growth performance and digestive enzyme activity of the shrimp Penaeus vannamei was investigated. Photosynthetic bacteria and Bacillus sp. were added to shrimp basal diets as probiotics at three concentrations: T-1, 2 g kg − 1 (1 g kg − 1 lyophilized photosynthetic bacteria cells (PSB) and 1 g kg − 1 lyophilized Bacillus sp. (BS)); T-2, 10 g kg − 1 (5 g kg − 1 PSB and 5 g kg − 1 BS); and T-3, 20 g kg − 1 (10 g kg − 1 PSB and 10 g kg − 1 BS). Twelve aquaria with three replicates for each treatment group and the Control group were used. After 28 days, shrimp receiving the diets supplemented with probiotics showed significantly better growth performance than those fed the basal diet (Control). The mean digestive enzyme activity of each treatment groups was significantly different ( P P

Abstract: 2-methylisoborneol (2-MIB) and geosmin are two odor-causing compounds that are difficult to remove and the cause of many consumer complaints. In this study, we assessed the degradation of 2-MIB and geosmin using a UV/persulfate process for the first time. The results showed that both 2-MIB and geosmin could be degraded effectively using this process. The process was modeled based on steady-state assumption with respect to the odor-causing compounds and either hydroxyl or sulfate radicals. The second order rate constants for 2-MIB and geosmin reacting with the sulfate radical ( SO 4 − ) were estimated to be (4.2 ± 0.6) × 10 8 M −1 s −1 and (7.6 ± 0.6) × 10 8 M −1 s −1 respectively at a pH of 7.0. The contributions of the hydroxyl radical (OH ) to 2-MIB and geosmin degradation were 3.5 times and 2.0 times higher, respectively, than the contribution from SO 4 − in Milli-Q water with 2 mM phosphate buffer at pH 7.0. The pseudo-first-order rate constants ( k o s ) of both 2-MIB and geosmin increased with increasing dosages of persulfate. Although pH did not affect the degradation of 2-MIB and geosmin directly, different scavenging effects of hydrogen phosphate and dihydrogen phosphate resulted in higher values of k o s for both 2-MIB and geosmin in acidic condition. Bicarbonate and natural organic matter (NOM) inhibited the degradation of both 2-MIB and geosmin dramatically through consuming OH and SO 4 − and were likely to be the main radical scavengers in natural waters when using UV/persulfate process to control 2-MIB and geosmin.