Modeling Cyber Loss Severity Using a Spliced Regression Distribution with Mixture Components

Cyber losses in terms of number of records breached under cyber incidents commonly feature a significant portion of zeros, specific characteristics of mid-range losses and large losses, which make it hard to model the whole range of the losses using a standard loss distribution. We tackle this modeling problem by proposing a three-component spliced regression model that can simultaneously model zeros, moderate and large losses and consider heterogeneous effects in mixture components. To apply our proposed model to Privacy Right Clearinghouse (PRC) data breach chronology, we segment geographical groups using unsupervised cluster analysis, and utilize a covariate-dependent probability to model zero losses, finite mixture distributions for moderate body and an extreme value distribution for large losses capturing the heavy-tailed nature of the loss data. Parameters and coefficients are estimated using the Expectation-Maximization (EM) algorithm. Combining with our frequency model (generalized linear mixed model) for data breaches, aggregate loss distributions are investigated and applications on cyber insurance pricing and risk management are discussed.

Effects of Light and Temperature on Uptake andDistribution of Nitrogen, Phosphorus and Potassiumof Cucumber in Solar Greenhouse

The influence of light and temperature conditions inside solar greenhouse of winter-spring and autumn-winter crop in northern China on uptake and distribution of nitrogen. phosphorus and potassium of cucumber was studied. The results showed that plant root development and uptake and distribution of N, P and K benefited more from inside light and temperature changes in winter-spring crop. Root volume and root activity increased more rapidly in winter-spring than in autumn-winter. Uptake of total N, P2O5 and K2O increased with plant development in winter-spring, and declined in autumn-winter crop. Distribution of total N, P2O5 and K2O at different part of cucumber at fruit bearing stage was significantly influenced by inside light and temperature of solar greenhouse. Total N, P2O5 and K2O were mainly distributed to leaves and stems at early stage, and increasingly to fruits after fruit bearing.

Calculation methods of lubricant film pressure distribution of radial grooved thrust bearings

In order to calculate the pressure distribution of radial grooved thrust bearing, analytical and numerical methods were applied respectively. Grooved region and land region were linked by u- sing the mass conservations principle at the groove/land boundary in each method. The block-weight approach was implemented to deal with the non-coincidence of mesh and radial groove pattern in nu- merical method. It was observed that the numerical solutions had higher precision as mesh number exceed 70 x 70, and the relaxation iteration of differential scheme presented the fastest convergence speed when relaxation factor was close to 1.94.

Vibration analysis of foam plates based on cell volume distribution

In this paper, vibration analysis of irregular-closed-cell foam plates is per- formed. A cell volume distribution coefficient is introduced to modify the original Gibson- Ashby equations of effective Young＇s modulus of foam materials. A Burr distribution is imported to describe the cell volume distribution situation. Three Burr distribution pa- rameters are obtained and related to the cell volume range and the diversity. Based on the plate theory and the effective modulus theory, the natural frequency of foam plates is calculated with the change of the cell volume distribution parameters. The relationship between the frequencies and the cell volumes are derived. The scale factor of the average cell size is introduced and proved to be an important factor to the performance of the foam plate. The result is shown by the existing theory of size effects. It is determined that the cell volume distribution has an impact on the natural frequency of the plate structure based on the cell volume range, the diversity, and the average size, and the impact can lead to optimization of the synthesis procedure.

区域地震记录揭示的2023年甘肃积石山6.2级地震震源破裂过程

基于有限断层模型反演方法,利用区域宽频带地震波形数据,反演了2023年12月18日甘肃临夏积石山6.2级地震的震源破裂过程,获得了积石山地震破裂滑动时空分布:此次地震是逆冲兼少量走滑型地震,破裂持续时间约为9 s,主体能量在前6 s释放,地震破裂主要沿断层走向向NW方向拓展,计算得到的标量地震矩为1.39×10^(18)N·m,相当于M_(W)6.02,破裂尺度约10 km左右,最大同震滑动量为35 cm。

铝型材静电粉末喷涂模型的研究与应用

针对实际生产中企业为实现铝型材表面均匀涂层而耗费巨大人力物力的问题,提出了一种适用于生产实际的变高斯分布模型。通过对铝型材静电粉末喷涂影响因素的分析,使用控制变量法进行定点和连续喷涂实验,获得涂层厚度实验数据,基于高斯分布对定点实验数据进行拟合,对于拟合模型存在的远离中心截面偏差问题,采用变峰值宽度的方式对模型进行优化修正,进一步提高了模型与实验数据的拟合程度,在此基础上,通过实验数据分析了静电电压、粉末流量、喷涂速度对膜厚分布的影响,建立了不同参数下静电粉末喷涂涂层的变高斯分布模型。最后进行了喷涂实验,铝型材成品的膜厚分布情况符合模型仿真预测的结果,表明该模型能准确预测不同参数下铝型材的膜厚分布情况,在生产实际中,模型的应用可以为均匀涂层提供可靠的仿真参考和生产指导,有效减少企业调试参数的次数,提高了企业的生产效率。

乌溪江水库富营养化程度及其影响因子时空分布探讨

了解乌溪江水库主要水质指标的时空分布特征,探究其营养化程度的变化趋势,可为改善乌溪江水库水质、维护其生态系统提供数据参考。2019-2020年,对丽水市乌溪江水库的7个采样点(S1~S7)的水温(WT)、水深(WD)、pH、总氮(TN)、总磷(TP)、叶绿素a(Chl-a)等理化因子进行监测,并分析对比综合营养指数和理化因子等关键指标在不同时期的分布特征。结果显示,乌溪江水库的营养盐浓度呈现春夏高秋冬低、从上游(S1)至下游(S7)逐渐下降的趋势,平均综合营养指数从47.1(S1)下降到32.5(S7),整体上属于中营养化水库。TP浓度在0.002~0.040 mg/L,平均值为0.012 mg/L;TN浓度在0.412~2.826 mg/L,氮的主要赋存形式为硝酸盐。Chl-a含量均值为3.77μg/L,河流区的Chl-a含量显著高于下游的过渡区和湖泊区。分析表明汛期地表径流带来的富营养化压力最大,同时也是氮磷等外源性营养盐输入水体的主要途径;WT、p H、TP与Chl-a含量中等程度相关,水库生态系统具备很强的净化能力,但近年来富营养化程度加剧。

郑州市中心城区高铁锰地下水成因与分布规律

于2020年在郑州市中心城区布设273个监测点采集浅层地下水样品,分析地下水中铁和锰的空间分布特征。结果表明,研究区浅层地下水出现高铁锰现象的原因为区内第四纪中更新统和上更新统沉积物中铁锰质结核及浸染经淋溶进入地下水;浅层地下水中铁和锰含量具有伴生关系,铁锰超标区域相对集中,高铁锰区主要分布在黄河南岸局部地区;该区域浅层地下水为还原环境,有利于铁和锰的富集,pH值大多在7.1~8.0范围内,呈弱碱性,沿地下水径流方向,铁和锰含量随硝酸盐含量增加而降低,随硫酸盐和氯化物含量增加而增加。

综合性体育馆暖通空调设计的要点分析

通过对综合性体育馆空调负荷分析,赛时及赛后负荷组成,空调负荷分布特点指导冷热源选型及多种能源形式配置。分析比赛区空间气流组织形式及围绕二次回风的设计方法。比较了多种能源方案及气流组织,对冷热源的设计选型原则及BIM(Building Information Modeling,建筑信息模型)技术的应用进行总结。

Floristic diversity, regeneration status, and vegetation structure of woodlands in Metema Area, Amhara National Regional State, North-western Ethiopia

We studied woodland vegetation in broad-leaved deciduous woodlands of Metema in northwestern Amhara regional state, Ethiopia Our objective was to describe plant species composition, diversity, re- generation status, and population structure by a selective approach with a systematic sampling design. A total of 74 quadrats （each for 25 m x 25 m, spaced at intervals of 150--200 m） were sampled along established tran- sect lines following the homogeneity of the vegetation. Vegetation data including cover-abundance, height, diameter at breast height （DBH）, and numbers of seedlings and saplings of woody species were analyzed using Excel spreadsheet, Shannon Weiner diversity index, and PAST version 1.62. A total of 87 vascular plant species of 74 genera and 36 families were recorded. The dominant family was Fabaceae represented by 16 （18.39 %） species of 13 genera. Shannon Weiner diversity and evenness were 3.67 and 0.82, respectively, which showed that the area was en- dowed with rich floral diversity evenly distributed. The vegetation structure, as quantified by cumulative diameter class frequency distribution, plotted as an interrupted inverted-J- shape pattern with a sharp decrease in the 2nd diameter class. This indicated poor vegetation structure. The diameter classes frequency distributions of selected species plotted in four general patterns i.e., interrupted Inverted-J-shape, J-shape, Bell-shape and Irregular-shape. In conclusion, although the area showed high floral diversity and evenness, woody species including Sterculea setigera, Boswellia papyrifera, and Pterocarpus lucens showed lowest recruitment of seedlings and saplings.

急性缺血性脑血管病患者脑动脉粥样硬化性狭窄分布及危险因素

目的分析急性缺血性脑血管病患者脑动脉粥样硬化性狭窄的分布情况及危险因素。方法选取江苏大学附属徐州医院神经外科2018-02—2021-02收治的256例急性缺血性脑血管病患者为研究对象,分析病例资料和数字血管造影检查结果,探讨动脉粥样硬化性狭窄分布情况和危险因素。结果256例患者有狭窄病变600支,407支为颅内动脉狭窄,占67.83%;193例为颅外动脉狭窄,占32.17%。前循环和后循环分别为412支和188支,分别占68.67%和31.33%;107支血管累及大脑中动脉,占17.83%,为最常见累及血管。重度狭窄患者C反应蛋白(2.45±0.48)ng/L,白细胞介素-6水平(268.96±37.12)pg/L,中度狭窄患者C反应蛋白和白细胞介素-6水平分别为(2.36±0.54)mg/L和(252.55±43.72)pg/L;轻度狭窄患者C反应蛋白和白细胞介素-6水平分别为(2.21±0.32)mg/L和(244.78±40.32)pg/L,组间对比有统计学差异(P<0.05)。Logistic多因素分析显示,颅内动脉狭窄以高血压和糖尿病为独立危险因素;颅外动脉狭窄以性别、年龄、高血压和糖尿病为独立危险因素;同时狭窄者以性别、年龄、高血压、冠心病和糖尿病为独立危险因素,均存在统计学差异(P<0.05)。结论急性缺血性脑血管病患者脑动脉粥样硬化性狭窄以颅内动脉狭窄为主,前循环狭窄更为多发,主要累及大脑中动脉,脑动脉粥样硬化性狭窄以高血压和糖尿病为独立危险因素。

Improved quantum randomness amplification with finite number of untrusted devices based on a novel extractor

Quantum randomness amplification protocols have increasingly attracted attention tbr their tantastic ability to ampllI~, weak randomness to almost ideal randomness by utilizing quantum systems. Recently, a realistic noise-tolerant randomness amplification protocol using a finite number of untrusted devices was proposed. The protocol has the composable security against non-signalling eavesdroppers and could produce a single bit of randomness from weak randomness sources, which is certified by the violation of certain Bell inequalities. However, the protocol has a non-ignorable limitation on the min- entropy of independent sources. In this paper, we further develop the randomness amplification method and present a novel quantum randomness amplification protocol based on an explicit non-malleable two independent-source randomness extractor, which could remarkably reduce the above-mentioned specific limitation. Moreover, the composable security of our improved protocol is also proposed. Our results could significantly expand the application range for practical quantum randomness amplification, and provide a new insight on the practical design method for randomness extraction.

发动机涡轮叶片孔探眼动行为的研究

高压涡轮叶片的孔探检测是航空发动机维修中最重要的检测项目,为了研究不同经验下的发动机涡轮叶片孔探的眼动行为,通过眼动仪获取不同孔探人员检测过程中的眼动数据,并依据高压涡轮叶片的本体结构将检测过程中人员的视野平面划分成了4块注视区域,并利用马尔可夫链理论对叶根、叶尖、叶身、前缘这4块注视区域进行求解,获取了视觉一步转移概率以及注意力平稳分布矩阵,根据计算结果发现熟练孔探人员在检测过程中会反复确认涡轮叶片的前缘和叶尖这两个特定结构区域是否存在故障,而非熟练孔探人员则没有一定的针对性更偏向视野平面的全域搜索,可见通过该研究能有效了解经验丰富的孔探人员在孔探过程中的视觉搜索模式,帮助缺乏检测经验的人员学习孔探检测技巧,提升检测效率。

城市地下工程典型爆炸危险源辨识

二十一世纪,在国内外飞速发展的城市地下工程施工和运营过程中,突发爆炸事件频频发生,造成巨大的人员伤亡和严重的财产损失。本文研究了城市地下工程典型爆炸危险源,整理已有的爆炸危险源分类方法,提出针对城市地下工程典型爆炸危险源的分类方法。分析了城市地下工程爆源的空间分布特征,描述了城市地下工程突发爆炸的可能位置。同时给出了城市地下工程各类爆炸的发生原因,分析了城市地下工程典型突发爆炸的诱发机理及条件,总结了对应的预防措施。本文针对城市地下工程典型爆炸危险源进行辨识,期望帮助企业和政府做好预防措施和应急预案,降低城市地下工程爆炸事故的发生率。

基于主从博弈的配电网与多微网双层优化研究

针对配电网与多微网系统(multi-microgrids,MMG)间的电能交互和能源协调问题,提出了一种配电网运营商(distribution system operator,DSO)设定电能交互价格的方法,以协调MMG系统的能量交易。构建了DSO与MMG的电能交易框架,分析了两者的主从博弈关系,并引进P2G与CCS联合装置(P2G-CCS)改进传统CHP机组,以降低碳排放;建立了基于Stackelberg理论的DSO与MMG主从博弈优化模型,通过上层DSO设定电能交互价格,引导下层MMG系统运行优化,使其对DSO的决策进行响应;利用二分法分布式优化算法结合CPLEX求解器对所建立模型进行求解。结果表明,该文提出的博弈模型有效地协调了MMG的优化运行,在碳排放方面,证明了CCS-P2G的引入,有效减少了微网运行过程中的碳排放量。

混合型MMC器件损耗分布优化控制方法

全桥-半桥1:1混合型MMC在正常稳态下工作于半桥型MMC模式,全桥及半桥子模块充放电行为几乎一致,子模块器件损耗分布极不均衡,特别是在逆变工况下,半桥子模块下部IGBT损耗尤为突出。为此,提出了基于全、半桥两类子模块差异化控制的器件损耗分布优化方法。首先,解析计算子模块器件损耗,以明确损耗不平衡的原因。其次,为改善器件损耗分布,在不影响设备输出外特性前提下,提出全/半桥模组解耦控制方法。然后,通过分析模组平均开关函数对器件通态及开关损耗的影响机理,以降低半桥子模块下部IGBT损耗为目标,推导出最优模组平均开关函数。最后,通过MATLAB/Simulink及PLECS仿真验证解耦控制策略的可行性及其对损耗分布优化的有效性。

水杨酸甲酯缓释调控果园捕食性瓢虫控害效果

【目的】利用化学信息素调控天敌昆虫是害虫绿色防控的重要措施之一。明确应用新型缓释材料释放水杨酸甲酯对苹果园捕食性瓢虫的调控作用,以及对苹果绣线菊蚜的防治效果。【方法】连续2 a(年)调查了苹果园内苹果绣线菊蚜的种群消长动态以确定水杨酸甲酯的使用时间,处理区采用5×5的布局均匀悬挂水杨酸甲酯PE缓释管防治绣线菊蚜,分别以未做任何防治的果园和化学防治的果园为对照,调查捕食性瓢虫及苹果绣线菊蚜种群发生动态以及检测水杨酸甲酯缓释速率,并使用5种常用聚集度指标参数法分析水杨酸甲酯对捕食性瓢虫及苹果绣线菊蚜空间分布特征的影响。【结果】北京地区苹果园苹果绣线菊蚜的发生高峰期在5月底至6月中旬,在发生高峰期前1周悬挂水杨酸甲酯PE缓释管,处理区内捕食性瓢虫数量显著高于化学防治区,并且显著降低了苹果绣线菊蚜的发生数量;空间分布结果显示苹果绣线菊蚜在各苹果园区内均表现出边缘型聚集分布的特征。此外,研究结果也表明水杨酸甲酯PE缓释管的释放速率约为0.68 g·周^(-1)。【结论】水杨酸甲酯PE缓释管在果园持效期可超过4周,可以提高捕食性瓢虫的种群数量并降低苹果绣线菊蚜的发生数量,最高密度的苹果绣线菊蚜出现在水杨酸甲酯PE缓释管处理园区的边缘。

沙钢5800m^(3)高炉渣皮脱落的影响因素探析

沙钢5800m^(3)高炉炉墙热负荷不稳定,渣皮频繁脱落,炉况长期顺行难以维持。从操作制度和原燃料质量两方面对渣皮脱落的影响进行了分析,认为:①将中心气流指数Z值控制在11.5左右、边沿气流指数W值控制在0.6左右,既能稳定中心煤气流,又能发展边缘气流;②将边沿焦炭负荷控制在3.8,同时尽可能减少布料矩阵的变动,能够较好地调节煤气流分布;③将风口回旋区占比控制在0.48~0.52、鼓风动能控制在153kJ/s左右,能够吹透中心,增加炉缸的活跃性;(4)将铁水温度控制在1505℃以上、[Si]保持在0.40%~0.45%,有利于提高渣皮的稳定性。

喷嘴特性对双旋流燃烧室出口温度分布影响的实验研究

本文以双旋流全环燃烧室为试验对象,在高温高压试验条件下,通过调整全环燃油喷嘴的流量离散度和径向位置来研究其对出口温度分布的影响。试验结果表明,当喷嘴燃油流量离散度控制在±4%以内时,采用简单的大、小流量喷嘴间隔搭配的方案即可保证出口温度分布的均匀性;当燃油流量离散度放大到4%~8%时,采用本实验研究的搭配方案仍可保证出口温度分布的均匀性;当燃油流量离散度放大到10%时,通过调整喷嘴搭配方案已经无法保证出口温度分布均匀性。燃油喷嘴径向位置较火焰筒头部中心线偏离旋流杯腔道高度的11.5%以内时,不影响出口温度分布的均匀性。

国际人道法视角下疫苗接种的法律问题研究

明确国际人道法视角下疫苗接种的性质和范围;针对在战争及武装冲突时期国际疫苗分配失序、医务人员在疫苗接种的医务行为中决策的道德困境与特殊医务标志的保护困境,提出国际疫苗资源再分配、在国际人道法下尊重和保护并禁止惩罚从事任何符合医疗道德行为之医务工作人员的主张;就疫苗的人道主义通道和授权非政府组织提供人道主义援助等规则的完善,提出建设性的意见。