电力系统电压稳定分析方法及应用

介绍了电力系统电压稳定性的概念及其分类,对电压稳定性的静、动态分析方法进行了介绍和比较,最后综合运用连续潮流法、模态分析法、分岔理论以及时域仿真法对WSCC9节点系统进行了电压稳定性分析,结果表明综合方法能充分利用各种方法的优点,分析的结果是有效可靠的。     

军队参加抢险救灾的性质定位

军队参加抢险救灾,是国家宪法和法律赋予我军的职责使命;实践人民军队宗旨和任务的具体行动;我军遂行非战争军事行动的重要内容。     

离散小波变换在被动声目标识别中的应用

研究了战场被动声目标鲁棒特征参数的提取,分析了战场声信号与语音信号特征的相似性,提出基于MFCC参数的战场声目标识别方法。针对战场环境存在强噪声干扰情况,提出一种改进的MFCC特征参数(DWTMFCC)提取方法,该方法将小波分析和MEL倒谱分析结合,提高了特征参数的鲁棒性。仿真结果表明:在噪声条件下,利用DWTMFCC参数进行声目标识别,平均识别率比MFCC参数高出3.134个百分点,信噪比为5dB时,识别率仍达到93.67%。     

A Markovian model for process setup and improvement

We examine the setup and improvement policies for a production process with multiple performance states. Assume that the production process deteriorates randomly over time, following a Markovian process with known transition probabilities. In order to reduce the production cost incurred because of process deterioration, the process is inspected at the end of each period. Then one of three actions may be taken: do nothing, perform routine process setup, or perform routine setup and process improvement. The routine setup operation returns the process to its best performance state, whereas the process improvement action may reduce future production and setup costs and improve the process-state transition probabilities. A discounted Markovian model is formulated to find the strategy that minimizes the total cost of operating the production process. © 1997 John Wiley & Sons, Inc. Naval Research Logistics 44: 383–400, 1997     

Bicriteria scheduling on a single batching machine with job transportation and deterioration considerations

We study a single batching machine scheduling problem with transportation and deterioration considerations arising from steel production. A set of jobs are transported, one at a time, by a vehicle from a holding area to the single batching machine. The machine can process several jobs simultaneously as a batch. The processing time of a job will increase if the duration from the time leaving the holding area to the start of its processing exceeds a given threshold. The time needed to process a batch is the longest of the job processing times in the batch. The problem is to determine the job sequence for transportation and the job batching for processing so as to minimize the makespan and the number of batches. We study four variations (P1, P2, P3, P4) of the problem with different treatments of the two criteria. We prove that all the four variations are strongly NP‐hard and further develop polynomial time algorithms for their special cases. For each of the first three variations, we propose a heuristic algorithm and analyze its worst‐case performance. For P4, which is to find the Pareto frontier, we provide a heuristic algorithm and an exact algorithm based on branch and bound. Computational experiments show that all the heuristic algorithms perform well on randomly generated problem instances, and the exact algorithm for P4 can obtain Pareto optimal schedules for small‐scale instances. © 2014 Wiley Periodicals, Inc. Naval Research Logistics 61: 269–285, 2014     

三补偿阳极的电场特性建模和优化计算

为深入研究阳极数量和安装位置对舰船电场特性的影响,在分析单个和两个阳极情况时电场特性的基础上,通过多群进化规划算法对电场分布进行优化计算,建立数学模型并仿真分析了采用三补偿阳极时舰船周围水下电场的分布情况,得到了三个补偿阳极对于舰船电场防护效果的影响.最后,进行实船安装三个阳极的电场测量分析实验,实验结果与仿真结果一致,证明该方法对舰船阳极的安装数量和位置有直接指导作用.     

农学专业教学生产实习问题探讨

农学专业是一门实践性非常强的专业,其中教学生产实习是专业教育过程中极为重要的环节,其成败直接影响农学专业学生的综合能力和水平。经过多年指导农学专业教学生产实习的实践,现就农学专业教学生产实习的特点和在新时期下存在的主要问题进行分析,并提出相应的改革措施。     

回归型支持向量机的机翼结冰冰型预测

飞机结冰严重威胁着飞行安全。针对机翼结冰冰型预测时不确定性因素较多、难以准确预测的问题,提出了一种基于回归型支持向量机的机翼结冰冰型预测方法。在建立冰型模型的基础上,利用回归型支持向量机(Support Vector Regression,SVR)获得冰型多项式系数,从而预测出相关飞行条件和大气条件下的冰型。仿真结果表明,该方法具有较好的预测能力,可以及时提供可靠的结冰信息,为保证结冰条件下的飞行安全提供了保障。     

简谐外磁场环境下海森堡XXZ模型的热力学纠缠

研究了在简谐外磁场环境下的海森堡XXZ模型,并通过计算解出热力学纠缠度。模拟表明,取不同的各向异性参数时,系统的热力学纠缠度对外部磁场和环境温度的变化比较敏感,并随简谐磁场的变化表现出周期性。固定各向异性参数时,热纠缠度随温度的增加呈现衰减趋势;增大各向异性参数时,热纠缠度则很快地趋于零,其对应临界温度也迅速降低。