一类脉冲扩散渔业系统的优化收获策略

研究了一类在周期环境中具有脉冲扩散和收获的近远海渔业模型的动力学行为和优化控制问题.利用脉冲微分系统的基本理论和一些分析技巧,研究获得了系统正周期解存在和稳定的条件.进一步,在系统保持周期变化的条件下,考虑收获成本因素,以最大经济净收益为目标,研究收获努力量对收益的影响,获得了最优控制策略及最优经济净收益的具体表达式.     

最佳整体印刷工艺流程

印刷业一直在重点研究一个问题:如何缩短工艺周期,让印刷品在最短的时间内交付给用户,而且印刷质量和成本收益间又有最优的组合和平衡.     

一类具有Beddington-DeAngelis功能反应捕食系统收获模型的稳定性

研究一类具有双线性密度制约及Beddington-DeAngelis功能反应的捕食系统收获模型.运用微分方程定性稳定性理论讨论系统正平衡点的性态,得到其局部渐近稳定及全局渐近稳定的充分条件,利用Pontryagin最大值原理得到系统的最优收获策略.     

周期脉冲L-V竞争系统解的全局渐近性质

研究一类具有脉冲效应的Lotka-Volterra周期竞争系统.利用脉冲微分系统的比较原理,Floquet理论及一些分析技巧研究了系统解的有界性及渐近性质,并建立了系统正周期解存在惟一及全局吸引的条件.最后用实例进行数值模拟,解释说明了所获得的主要结论.     

The global asymptotic properties of the solutions of periodic imulsive L-V competition system

研究一类具有脉冲效应的Lotka-Volterra周期竞争系统.利用脉冲微分系统的比较原理,Floquet理论及一些分析技巧研究了系统解的有界性及渐近性质,并建立了系统正周期解存在惟一及全局吸引的条件.最后用实例进行数值模拟,解释说明了所获得的主要结论.     

最佳整体印刷工艺流程

印刷业一直在重点研究一个问题 如何缩短工艺周期,让印刷品在最短的时间内交付给用户,而且印刷质量和成本收益间又有最优的组合和平衡。这需求导致各公司在印前传统工艺的基础上不断改进 如从最早的暗室拷贝到电分,到激光照排,到桌面出版系统,再到直接制版等等。而后端的油墨加印刷机的方式却因没有更优越的取代系统而延用至今并仍占主流。     

电力资产全寿命周期管理

资产全寿命周期管理是从长期效益出发,实现资产在整个寿命周期中收益和成本最优。对电网资产开展全寿命周期管理,将在确保规划合理、工程优质、电网安全、设备可靠的同时,延长资产使用寿命,降低整个寿命周期的成本投入,实现电力资产可靠性和经济性的综合优化,避免片面追求可靠性或经济性。     

具有脉冲的生态传染病模型周期解的存在性(英文)

研究了一个具有脉冲周期的传染病模型.利用Floquet理论给出了平凡周期解、半平凡周期解及无病周期解线性稳定的条件.利用重合度理论,得到了正周期解的存在性.给出了系统持久的充分条件.数值模拟验证了理论结果的正确性.     

一类具有分布时滞的脉冲Logistic系统的周期正解

利用Gaines和Mawhin的重合度理论,研究了一类具有分布时滞的脉冲Logstic系统,获得了该系统至少存在一个周期正解的充分条件.     

具有害虫综合控制策略的捕食系统的动态行为

研究了具有两种不同脉冲控制序列的捕食与被捕食模型的动态行为,通过随机的喷洒杀虫剂或投放自然天敌,得到了捕食系统害虫根除周期解的全局稳定性的临界值．数值模拟分析了喷洒杀虫剂和投放天敌的次数如何影响害虫综合控制,为成功的害虫控制策略提供依据．     

具密度制约的Holling Ⅱ类捕食收获系统的定性分析

研究一类具有双密度制约的HollingⅡ类功能反应的捕食系统收获模型,运用微分方程定性稳定性理论分析了模型平衡点的性态,给出了系统极限环不存在的充分条件,利用Pontryagin最大值原理得到系统的最优捕获策略.     

最优广告策略的随机控制模型研究

建立了一个关于广告策略的随机控制模型．在模型的基础上，研究了最优广告策略的存在性和充要条件．     

Economic evaluation of the breeding goal for Norwegian Red dairy cattle

In this paper, a translog profit function was applied to estimate the economic values of the traits included in the breeding goal for Norwegian Red dairy cattle. The following 10 traits are included in the breeding goal: milk, meat, mastitis resistance, fertility, calving difficulties, stillbirths, other diseases, udder, temperament, and legs. An empirical implementation that locally approximates the unknown true profit function was suggested and estimated, taking farm heterogeneity into account. The model was applied to a panel data set of 3,259 Norwegian dairy farms over the period 1999 to 2003. Panel data, also called longitudinal or cross-sectional time-series data, are multiple cases (cows, farms, countries, etc.) observed over 2 or more time periods. The data set consisted of farm-level data, including production and economic data from the farm and the estimated breeding values for each cow's sire. The estimated economic values make it possible to test whether genetic selection has been profitable for the farmer, and the extent to which the currently used economic values were optimal during the period 1999 to 2003. Although the translog profit function is quite flexible, it is rather complex, and a simplified version of the model, a Cobb-Douglas profit function, was also estimated. However, the hypothesis that this simpler function adequately describes the data compared with the full translog model was rejected. Further, the hypothesis that the estimated breeding values are profit neutral was rejected (i.e., the hypothesis that there are no interactions between input and output prices on one hand and estimated breeding values on the other). These results indicated that selection not only leads to a parallel shift in profits, but also to changes in input use. Seven of the 10 traits had a significant effect on the farmers’ profit. The 3 traits that were not significant were calving difficulty, stillbirth, and other diseases. The results showed that the breeding program for Norwegian Red cattle has been fairly successful in improving farmers’ profits. However, a slight modification of the breeding goal, such as a reduction in the weights for stillbirths and other diseases and an increase in the weights for meat and temperament, would increase farm profits.     

一类线性Normal脉冲系统的稳定性(英文)

讨论了一类线性正规脉冲系统的稳定性,给出了线性正规脉冲系统全局指数稳定和扰动系统全局指数稳定的充分条件,推广了已有结果.     

纸浆洗涤过程中稀释因子的优化

基于浆料洗涤系统的整体工程思想,对洗浆系统和蒸发系统进行了物料衡算,建立了纸浆洗涤用水和稀释因子的最优化模型,并通过罚函数,将约束问题转化为无约束问题,对模型进行了寻优控制.实践表明,该方法可以找到最优稀释因子,减少了费用,降低了生产成本.     

Heat removal from heat-sensitive foods: an economic approach to the transient behaviour of finned surfaces

The transient behaviour of a fin used to remove heat from the surface of a rectangular-shaped liquid food container is studied in dimensionless form leading to a single-term equation for the heat transferred in relation to time. For heat-sensitive foods the rate of heat removal is important so an economic value can be ascribed to such removal to balance the captial investment on finning the container. An optimal solution can be found in order to maximize the net profit involved using the fin length as the independent variable.     

棉田免耕套栽油菜施肥效果及肥料适宜用量研究

在棉田免耕套栽条件下,研究了油菜氮磷钾（NPK）肥施用效果及肥料适宜用量。结果表明,合理施用氮磷钾肥促进了油菜的营养生长和生殖生长,从而显著提高了油菜的产量和经济效益,N、P、K三要素增产效果依次为：N〉P〉K。通过对肥料效应模型的筛选,得出在试验条件下,油菜氮（N）、磷（P2O5）、钾（K2O）的适宜推荐用量分别为205kg／hm^2、76kg／hm^2、35kg／hm^2。     

新疆三个产地西拉葡萄成熟期品质变化及最适采收期预测

为研究新疆各产地西拉酿酒葡萄成熟指标的变化规律及其最适采收期,自果实转色期开始,以不同采收期哈密、昌吉及和硕西拉葡萄为研究对象,持续监控其理化指标和酚类物质含量变化,分析理化指标与多酚指标的相关性,并对不同产地及采收期的西拉酿酒葡萄进行主成分分析（PCA）,确定最适采收期。结果表明,不同采收期各产地西拉葡萄理化指标及多酚含量差异显著（P＜0.05）,且理化指标与多酚含量联系紧密;主成分分析结果表明,哈密、昌吉及和硕西拉葡萄最适采收期分别为9月9日、9月11日及9月3日。     

Lifetime profit as an individual trait and prediction of its breeding values in Spanish Holstein cows

Genetic parameters for lifetime profit and some productive traits were estimated from records of 42,401 Holstein cows with first calving before May 1996 from Navarra and Basque Autonomous Regions of Spain. Profit from the first, first two, and first three lactations were tested as early measures of profitability. Profit prediction was tested for another population of 2127 cows using selection indexes (Type-Production and economic indexes) and multitrait analysis for directly predicting profit from first-lactation records. High genetic correlations of actual profit with estimated profit from the first two or first three lactation records, (0.97 and 0.99, respectively) suggest that lifetime profit can be accurately estimated from data in second lactation. Profit was positively correlated to production traits (0.79 to 0.83), functional herd life (0.38), mature body weight (0.25), and days in milk (0.35), but genetic correlation was found to be close to zero with calving interval. Complicated relationships among profit and economic traits (i.e., calving interval, days in milk, and functional herd life) were found. Although the correlation between calving interval and profit was near zero, calving interval was the most important trait after production in prediction of sire profit by a stepwise regression analysis. Profit breeding values from multitrait analysis obtained higher correlation (0.48) with actual profit than Spanish official Type-Production index ICO (0.44) and economic index MEG (0.46). A correlation of 0.49 between profit breeding values and the economic index MEG2002, where stature and calving interval were included as new traits, was obtained.     

烤烟品种翠碧一号上部叶适宜采收方式研究

为探究翠碧一号上部叶最佳采收方式,提高烟叶质量和可用性。以翠碧一号上部充分成熟烟叶为材料,设置3片、4片、5片、6片一次逐叶采收和5片、6片一次带茎采收6个处理,研究了上部叶不同采收方式对烤后烟经济性状、外观、化学成分、感官及致香物质的影响。结果表明,翠碧一号上部叶不同采收方式的烤后烟质量存在显著差异,对等级结构、均价、中部烟比例和感官质量等进行综合分析看出,6片一次采收烤后烟叶整体质量和经济效益最好,其中6片一次逐叶采收方式更有利于提高上等烟比例、均价和中部烟比例,分别比对照提高了8.56%、4.95元/kg和8.15%,6片一次带茎采收方式更有利于提高上中等烟比例和致香物质含量,分别提高了8.13%、20.22%,且显著改善感官质量。可见,在生产实际中,翠碧一号上部叶最佳采收方式为6片叶充分成熟时一次采收烘烤。