基于MapReduce模型带准备时间的平行机调度优化

研究了一类基于MapReduce模型的平行机调度问题.每个工件包含Map和Reduce两道加工工序,Map工序可以分割为若干个子任务,并且在多台平行机上同时并行加工,Reduce工序只有在该工件的所有Map工序的子任务加工完成后才能进行,而且Reduce只能在一台机器上加工且不可中断.结合工件具有释放时间和加工准备时间等约束,以最小化最大完工时间为目标,构建了混合整数规划模型,并设计了采用差分变异策略和逐维Levy扰动机制的改进正弦余弦算法来求解该模型.最后,利用数值仿真实验与标准正弦余弦算法及遗传算法进行对比,实验结果表明,运用改进正弦余弦算法求解的结果与下界值的平均相对偏差GAP为3.02%,较标准正弦余弦算法以及遗传算法的效果提升显著,显示了该改进算法的有效性.     

冰鲜杂鱼与颗粒饲料对斜带石斑鱼的对比饲养效果

选择冰鲜杂鱼和2个市场反映较好的石斑鱼配合饲料产品,分别对斜带石斑鱼(Epinephelus coioides)进行饲喂效果实验,通过生长性能、体成分、群体离散度以及养殖成本分析,评价冰鲜杂鱼和配合颗粒饲料在斜带石斑鱼养殖效果上的优劣.同一批培育的斜带石斑鱼幼鱼,随机分成3组(冰鲜杂鱼组、石斑鱼颗粒饲料1组和石斑鱼颗粒...     

凝结芽孢杆菌的生物学特性及其在水产养殖中的应用

凝结芽孢杆菌(Bacillus coagulans)呈杆状,两端钝圆,为革兰氏阳性菌,能分解糖类生成L-乳酸,为同型乳酸发酵菌。凝结芽孢杆菌除具有和乳酸菌及双歧杆菌同样的营养和免疫功效外,还具有耐酸、耐热、耐盐、容易培养和保存的特点,在水产养殖中具有维持肠内的生态平衡,促进营养物质的吸收,提高机体免疫力,净化养殖水环境的作用。目前,凝结芽孢杆菌已作为饲料添加剂和水质改良剂在水产养殖中使用,具有很大的应用前景。     

Study on the influence of the subsurface buoy's vibration on the vector sensor due to ocean current

Subsurface buoy systems,especially equipped with the vector sensor,have more and more extensive applications in military and civilian regions.However,their acoustic performances are constrained by the vibration resulting from the unavoidable ocean current in some degree.The influence of such vibrations is quantitatively analyzed by means of modeling the simplified models of two deployment configurations involving the positive buoyant buoy and neutral buoy system.The corresponding formulas are deduced respectively for the deployment configuration buoy systems in the motion state firstly.Then the simulation software is developed and some numerical simulations are put up via the Runge-Kutta method.The simulation results and theoretical analysis indicate that the neutral buoy will be an excellent design protocol in engineering application in comparison with the positive buoyant buoy.     

盐度胁迫对非洲斑节对虾生理特征的影响

为探讨不同盐度梯度下非洲斑节对虾(Penaeus monodon)的盐度耐受性,本研究测定了盐度胁迫下对虾生长、渗透、抗氧化及消化指标的变化.实验设置4个盐度梯度(20,30,40,50),以30盐度组作为对照,进行为期35 d的喂养实验.实验结束时计算增重率(Weight Gain Rate,WGR)、特定生长率(S...