舰船交流电力系统短路电流的改进算法及计算软件的编制

针对中国国家军用标准方法（ＧＪＢ－１７３）在计算某型舰船电力系统短路电流时误差较大的情况,提出了一种新的具有较高计算精度的短路电流计算方法——改进算法．提供了一套用ＶｉｓｕａｌＢａｓｉｃ５．０编制的短路电流计算软件,该软件具有良好的人机对话能力和友好的界面,使用方便,且有较强的通用性     

电化教材的本质与功能结构简析

本文从认识论和时空观的角度提出教材发展中的三种载体、三种型式;论述了电化教材是“形象”螺旋回归的必然;从传统教材的质变,引伸出电化教材的选择性功能结构及其五大要素;阐述了电化教材在内容选取、表述方法、过程控制、超越时空等方面的“滞后”、“同步”、“超前”机动的综合时空观及其现实意义;最后明确指出:电化教学理论的土壤在于电化教材的建设及其运用。     

圆柱壳承受水下爆炸作用时的动响应

本文提出了有限水域内水下爆炸实验设计的一般考虑方法,结合实验结果得到了各种条件(λ/D)下圆柱壳受水下爆炸作用时的壁压分布规律,采用塑性动力学中绝对最小原理对结构响应进行了数值计算,给出了冲击波作用下圆柱壳响应的一种偏安全估算方法。     

SC-3466高速数传系统中差错控制系统的设计与实现

我们研制了并行高速 HF-Modem SC-3466,它的最高数据传输率可达2400bit/s,具有多种功能可供用户自由选择,能满足用户对数字话音及一般数据传输的要求。本文详细讨论了本系统中差错控制编码、交错与去交错技术的设计与实现。     

相空间有限元方法在解二维中子输运方程中的应用

本文采用相空间有限元方法求解了柱形临界多群中子输运问题。其中对于方程中的坐标变量用分片连续线性多项式作为试探函数,对于方程中的角度变量用分片连续双线性多项式作为试探函数。整个求解空间区域和角度区域分别采用三角形和矩形单元划分,然后利用迦辽金方法得到一个以网格点处角通量为未知数的线性联立代数方程组,方程组中的系数矩阵的存储采用了压缩存储技术。最后用高斯消元法解此有限元方程组,表明相空间有限元方法计算收敛性较好、计算精度高。     

阵列排序器的VHDL设计方法

ＶＨＤＬ是数字电路设计和描述的标准语言。讨论了脉动阵列结构的排序运算器及其改进电路,它们简洁的ＶＨＤＬ描述,经计算机的综合自动生成ＦＰＧＡ或ＡＳＩＣ的门级网表。实践证明,应用ＶＨＤＬ可以极大地提高设计效率。     

Estimating the economic impact of the 1973 Navy base closing: Models,tests, and an ex post evaluation of the forecasting performance

In 1973 the Defense Department made plans to close many Navy bases in the United States. Hardest hit was Rhode Island which would suffer a loss of 45.61% of the total cutback of 42,812 jobs. This paper describes two models which were built to forecast the severity of the economic impact in Rhode Island: one used the reduced form equation approach, and the other the simultaneous equations system approach. Tests on multicollinearity, specification, and serial correlation were conducted. An ex post evaluation of these two models' performance in forecasting then concludes the paper.     

Economic ordering decisions with market choice flexibility

Standard approaches to classical inventory control problems treat satisfying a predefined demand level as a constraint. In many practical contexts, however, total demand is comprised of separate demands from different markets or customers. It is not always clear that constraining a producer to satisfy all markets is an optimal approach. Since the inventory‐related cost of an item depends on total demand volume, no clear method exists for determining a market's profitability a priori, based simply on per unit revenue and cost. Moreover, capacity constraints often limit a producer's ability to meet all demands. This paper presents models to address economic ordering decisions when a producer can choose whether to satisfy multiple markets. These models result in a set of nonlinear binary integer programming problems that, in the uncapacitated case, lend themselves to efficient solution due to their special structure. The capacitated versions can be cast as nonlinear knapsack problems, for which we propose a heuristic solution approach that is asymptotically optimal in the number of markets. The models generalize the classical EOQ and EPQ problems and lead to interesting optimization problems with intuitively appealing solution properties and interesting implications for inventory and pricing management. © 2003 Wiley Periodicals, Inc. Naval Research Logistics, 2004.     

Mitigation effects on the reflected overpressure of blast shock with water surrounding an explosive in a confined space

The mitigation of blast shock with water has broad application prospects. Understanding the mitigation effects on the reflected overpressure of the explosion shock with water surrounding an explosive in a confined space is of great significance for military explosives safety applications. To estimate the effects of the parameters on the reflected overpressure of blasted shock wave, a series of experiments were carried out in confined containers with spherical explosives immersed in a certain thickness of water, and numerical simulations were conducted to explore the corresponding mechanisms. The results reveal that the reflected overpressure is abnormally aggravated at a small scaled distance. This aggravation is due to the high impulse of the bulk accelerated water shell converted from the explosion. With increasing scaled distance, the energy will be gradually dissipated. The mitigation effects will appear with the dispersed water phase front impacting at a larger scaled distance, except in the case of a dense water phase state. A critical scaled distance range of 0.7—0.8 m/kg1/3 for effective mitigation was found. It is suggested that the scaled distance of space walls should be larger than the critical value for a certain water-to-explosive weight ratio range (5—20).     

采用局域像素匹配的随机抽样一致改进算法

为提高图像拼接的配准精度和稳健性,提出基于局域像素匹配的随机抽样一致改进算法。在完成尺度不变特征变换算子或其他算子图像特征提取、特征匹配之后,利用独立于特征匹配点的局域像素,通过参考图像局域像素与映射的待拼接图像局域像素匹配,优选4对最佳特征匹配点,确定最佳单应矩阵。实验结果表明:与随机抽样一致经典算法相比,该方法未明显增加计算耗时,单应矩阵更准确,图像拼接稳健性更好。