Fishing and echolocation behavior of the greater bulldog bat,Noctilio leporinus,in the field

When hunting for fish Noctilio leporinus uses several strategies. In high search flight it flies within 20–50 cm of the water surface and emits groups of two to four echolocation signals, always containing at least one pure constant frequency (CF) pulse and one mixed CF-FM pulse consisting of a CF component which is followed by a frequency-modulated (FM) component. The pure CF signals are the longest, with an average duration of 13.3 ms and a maximum of 17 ms. The CF component of the CF-FM signals averages 8.9 ms, the FM sweeps 3.9 ms. The CF components have frequencies of 52.8–56.2 kHz and the FM components have an average bandwidth of 25.9 kHz. A bat in high search flight reacts to jumping fish with pointed dips at the spot where a fish has broken the surface. As it descends to the water surface the bat shows the typical approach pattern of all bats with decreasing pulse duration and pulse interval. A jumping fish reveals itself by a typical pattern of temporary echo glints, reflected back to the bat from its body and from the water disturbance. In low search flight N. leporinus drops to a height of only 4–10 cm, with body parallel to the water, legs extended straight back and turned slightly downward, and feet cocked somewhat above the line of the legs and poised within 2–4 cm of the water surface. In this situation N. leporinus emits long series of short CF-FM pulses with an average duration of 5.6 ms (CF 3.1 and FM 2.6) and an average pulse interval of 20 ms, indicating that it is looking for targets within a short range. N. leporinus also makes pointed dips during low search flight by rapidly snapping the feet into the water at the spot where it has localized a jumping fish or disturbance. In the random rake mode, N. leporinus drops to the water surface, lowers its feet and drags its claws through the water in relatively straight lines for up to 10m. The echolocation behavior is similar to that of high search flight. This indicates that in this hunting mode N. leporinus is not pursuing specific targets, and that raking is a random or statistical search for surface fishes. When raking, the bat uses two strategies. In directed random rake it rakes through patches of water where fish jumping activity is high. Our interpretation is that the bat detects this activity by echolocation but prefers not to concentrate on a single jumping fish. In the absence of jumping fish, after flying for several minutes without any dips, N. leporinus starts to make very long rakes in areas where it has hunted successfully before (memory-directed random rake). Hunting bats caught a fish approximately once in every 50–200 passes through the hunting area.     

A complete set of procedure for determination of multiresidue of pesticides in vegetables

A complete set of procedure for determination of multiresidue of pesticides in vegetables was presented in this paper.The complete set of procedure included three steps:bioassay,cholinesterase inhibition and GLC analysis.The samples could be identified to be contaminated with pesticides if 5% of house flies was knocked down in 50 tested house flies. Those samples contaminated with pesticides needed to be detected by AChE inhibition method.The qualitative and quantitative analyses were carried out by GLC.Recoveries ranged from 83.7% in Chinese cabbages to 105.6% in tomatoes for pyrethroids,and 84.0% in tomatoes to 102.7% in sweetbell redpeppes for organophosphorus compounds.Coefficients of variations ranged from 0.59% to organophosphorus compounds.Coefficients of variations ranged from 0.59% to 7.87% for pyrethroids. and 0.33% to 9.88% for organophosphorus compounds with vegetables. The complete set of procedure has been used successfully to analyze 7000 samples collected in Beijing. About 1% of the samp     

基于遗传集对分析的空气环境质量评价

集对分析是针对确定与不确定问题进行定量分析的一种方法,而表征差异度系数i的取值,一直没有确定的方法,即使在确定了同一度、差异度、对立度之后,整个联系数仍因i的不确定取值而呈现既确定又不确定的特征。文章将遗传算法应用于联系数表达式中i值的优化求解,使得联系数确定化,并结合实例对空气环境质量进行评价,评价结果与用其它方法评价结果比较表明该方法的可行性。     

基于重要度的系统可靠性分配方法

将系统的可靠性分配理论与故障树分析方法相结合,提出按故障树中各个基本事件(元件)的重要度大小进行可靠性分配的新方法.该方法可靠度的分配过程分两步:首先按可靠性再分配原理将系统的可靠度分配到各个最小割集;然后将需要调整可靠度的最小割集看成一个子系统,将最小割集的可靠度按基本事件重要度的大小分配到各个基本事件,即所谓二次分配模型.该方法不仅适用于仅有串、并联的简单系统,而且能够解决具有桥联结构的复杂系统的可靠性分配问题.     

Efficient Delineation of Nested Depression Hierarchy in Digital Elevation Models for Hydrological Analysis Using Level‐Set Method

In terrain analysis and hydrological modeling, surface depressions (or sinks) in a digital elevation model (DEM) are commonly treated as artifacts and thus filled and removed to create a depressionless DEM. Various algorithms have been developed to identify and fill depressions in DEMs during the past decades. However, few studies have attempted to delineate and quantify the nested hierarchy of actual depressions, which can provide crucial information for characterizing surface hydrologic connectivity and simulating the fill‐merge‐spill hydrological process. In this paper, we present an innovative and efficient algorithm for delineating and quantifying nested depressions in DEMs using the level‐set method based on graph theory. The proposed level‐set method emulates water level decreasing from the spill point along the depression boundary to the lowest point at the bottom of a depression. By tracing the dynamic topological changes (i.e., depression splitting/merging) within a compound depression, the level‐set method can construct topological graphs and derive geometric properties of the nested depressions. The experimental results of two fine‐resolution Light Detection and Ranging‐derived DEMs show that the raster‐based level‐set algorithm is much more efficient (~150 times faster) than the vector‐based contour tree method. The proposed level‐set algorithm has great potential for being applied to large‐scale ecohydrological analysis and watershed modeling.     

Estimation of Normal Variance Based on Balanced and Unbalanced Ranked Set Samples

In this paper we address the problem of estimation of the variance of a normal population based on a balanced as well as an unbalanced ranked set sample (RSS), which is a modification of the original RSS of McIntyre (1952).We have proposed several methods of estimation of variance by combining different unbiased between and within estimators, and compared their performances     

RS-PSO-ELM下腐蚀管道失效压力预测

为提高腐蚀管道失效压力的预测精度并简化其计算过程,提出基于粗糙集(RS)和粒子群算法(PSO)融合极限学习机(ELM)的腐蚀管道失效压力预测模型。通过属性约简提取影响失效压力的关键因素,选用PSO优化ELM的输入权值和隐含层偏差,将归一化的核心指标数据代入计算。结果表明:该模型预测结果与实际值基本一致,与单一ELM模型相比,预测结果的均方差(MSE)降至0.255;与其他蚀管道失效压力评价模型相比,该模型预测结果的绝对误差平均值降至0.32。     

建筑安全事故应急措施推理研究

为了加强对建筑安全事故历史案例经验的利用,提高建筑安全事故应急管理的信息化水平,对如何利用智能化技术制定事故应急措施进行研究。将规则推理引入案例推理中,建立了建筑安全事故应急措施推理模型。通过计算综合相似度,在案例库中检索出相似案例的基础上,根据关键属性运用规则推理对相似案例的应急措施进行适用性修改。计算特征属性权重时,利用灰色关联分析法对传统粗糙集方法进行改进,对冗余属性提出了灰色重要度的概念,避免了冗余属性权重为0的情况。选取基坑事故案例对模型进行实例分析,结果表明:建筑安全事故应急措施推理模型具有普遍适用性,可应用于事故应急管理。     

区域水资源可持续利用评价指标体系构建

基于区域水资源可持续利用评价指标体系（Indicators System for Sustainability AssessmentofWater Resources Use, ISSAWRU）构建的一般方法与步骤,论文围绕初始、优化和评价检验三个过程构建ISSAWRU;针对ISSAWRU构建中的指标信息重复和干扰问题,提出相关分析与粗糙集Horafa 属性约简算法相结合的方法实现指标体系的优化,并采用灰色系统理论与粗糙集耦合的评价方法对优化结果进行评价检验。以福建省为例,9 个设区市为研究单元,依据可持续发展理论,从水资源条件、开发利用状况、生态环境和社会经济四个方面,构建由30 项指标组成的初始ISSAWRU,通过筛选得到由12 项指标构成的优化ISSAWRU,进而对这两套指标体系进行评价。结果分析表明：相关分析与粗糙集Horafa 属性约简算法相结合的指标信息优化方案是可靠的;筛除重复和干扰指标信息,简化了繁杂的指标体系,降低了后续评价的计算复杂度,并且信息筛选后的优化ISSAWRU比初始ISSAWRU评价结果更合理。     

矿井风门闭锁系统

为了实现煤矿安全生产,各矿必须建立稳定的矿井通风系统.介绍一种可靠的井下通风设施-新型机械传动风门闭锁系统,已投入应用并取得良好效果.