Designing a Protection Scheme in Micro-Grid Systems with DG Using Central Protection Unite and Multiple Setting Group Protection Relays

Distributed generators now is widely used in electrical power networks, in some cases it works seasonally, and some types works at special weather conditions like photo voltaic systems and wind energy, and due to this continuous changes in generation condition, the fault current level in network will be affected, this changes in fault current level will affect in the coordination between protection relays and to keep the coordination at right way, an adaptive protection system is required that can adaptive its setting according to generation changes, the fault current level in each case is evaluated using ETAP software, and the required relay setting in each case is also evaluated using Grey Wolf Optimizer (GWO) algorithm, and to select suitable setting which required in each condition, to select the active setting group of protection relay according to generation capacity, central protection unite can be used, and to improve protection stability and minimizing relays tripping time, a proposed method for selecting suitable backup relay is used, which leads to decrease relays tripping time and increase system stability, output settings for relays in all cases achieved our constrains.

Android Malware Detection with Contrasting Permission Patterns

As the risk of malware is sharply increasing in Android platform,Android malware detection has become an important research topic.Existing works have demonstrated that required permissions of Android applications are valuable for malware analysis,but how to exploit those permission patterns for malware detection remains an open issue.In this paper,we introduce the contrasting permission patterns to characterize the essential differences between malwares and clean applications from the permission aspect Then a framework based on contrasting permission patterns is presented for Android malware detection.According to the proposed framework,an ensemble classifier,Enclamald,is further developed to detect whether an application is potentially malicious.Every contrasting permission pattern is acting as a weak classifier in Enclamald,and the weighted predictions of involved weak classifiers are aggregated to the final result.Experiments on real-world applications validate that the proposed Enclamald classifier outperforms commonly used classifiers for Android Malware Detection.

Function S-rough Sets and Their Law Characteristic

Function S-rough sets(Function Singular rough sets) are defined by R-function equivalence class which has dynamic characteristic, and a function is s law, function S-rough sets have law characteristic. Function S-rough sets has these forms: function one direction S-rough sets, function two direction S-rough sets and dual of function one direction S-rough sets. This paper presents the law characteristic of function one direction S-rough sets and puts forward the theorems of law-chain-attribute and law-belt. Function S-rough sets is s new research direction of the rough sets theory.

CONE-DIRECTED CONTINGENT DERIVATIVES AND GENERALIZED PREINVEX SET-VALUED OPTIMIZATION

By using cone-directed contingent derivatives, the unified necessary and sufficient optimality conditions are given for weakly and strongly minimal elements respectively in generalized preinvex set-valued optimization.

A NOTE ON THE JULIA SETS OF ENTIRE SOLUTIONS TO DELAY DIFFERENTIAL EQUATIONS

Let f be an entire solution of the Tumura-Clunie type non-linear delay differential equation.We mainly investigate the dynamical properties of Julia sets of f,and the lower bound estimates of the measure of related limiting directions is verified.

THE REGULARITY OF RANDOM GRAPH DIRECTED SELF-SIMILAR SETS

A set in Rd is called regular if its Hausdorff dimension coincides with its upper box counting dimension. It is proved that a random graph-directed self-similar set is regular a.e..

Contrast Test Between Direct Seeding and Seedling Transplanting of Diwangcai

To improve the yield of Diwangcai and explore its best cultivation way,direct seeding and seedling transplanting of Diwangcai were contrasted. The results showed that cumulative annual yield of Diwangcai by seedling transplanting was 16% higher than that by direct seeding.

S-rough sets and the discovery of F-hiding knowledge

Singular rough sets （S-rough sets） have three classes of forms： one-directional S-rough sets, dual of onedirectional S-rough sets, and two-directional S-rough sets. Dynamic, hereditary, mnemonic, and hiding properties are the basic characteristics of S-rough sets. By using the S-rough sets, the concepts of f-hiding knowledge, F-hiding knowledge, hiding degree, and hiding dependence degree are given. Then, both the hiding theorem and the hiding dependence theorem of hiding knowledge are proposed. Finally, an application of hiding knowledge is discussed.

Automatic Optimization of Chirp Setting Parameters in Medical Ultrasound Contrast Imaging

Medical ultrasound contrast imaging is a powerful modality undergoing successive developments in the last decade to date Lately, pulse inversion has been used in both ultrasound tissue harmonic and contrast imaging. However, there was a tradeoff between resolution and penetration. Chirp excitations partially solved the tradeoff, but the chirp setting parameters were not optimized. The present work proposes for the first time combining chirp inversion with ultrasound contrast imaging, with the motivation to improve the contrast, by automatically optimizing the setting parameters of chirp excitation, it is thus an optimal command problem. Linear chirps, 5 μm diameter microbubbles and gradient ascent algorithm were simulated to optimize the chirp setting parameters. Simulations exhibited a gain of 5 dB by automatic optimization of chirp inversion relative to pulse inversion. The automatic optimization process was quite fast. Combining chirp inversion with ultrasound contrast imaging led to a maximum backscattered power permitting high contrast outcomes and optimum parameters.

新质生产力视域下高等教育强国建设的实践路向——基于64个国家的比较分析

探究新质生产力视域下高等教育强国建设的实践路向,对于推进高等教育高质量发展,提升国际竞争力具有重要意义。研究基于新质生产力视角,以64个国家为样本,构建出高等教育强国建设的分析框架,提炼出入学与人才培养能力、科研与学科建设能力、知识与技术创新能力、全球影响力4个条件变量,并运用模糊集定性比较分析方法(fs QCA),探索条件变量之间的“多向互动”以及不同条件组合对高等教育强国建设产生的“联合效应”。研究发现,单一条件无法单独构成高等教育强国建设的必要条件;高等教育强国高水平建设路径有两条,分别是高等教育人才培养与科研学科建设的内生发展型、知识与技术创新赋能高等教育全球影响力的外生驱动型。为加快推进高等教育强国建设,应突破单一要素攻关,发挥多要素间的耦合协同,共同推进高等教育强国建设;立足人才培养与科研学科建设,释放高等教育强国建设的内生动力,提升服务新质生产力的能力;聚焦知识技术创新与全球影响力,激活高等教育强国建设的外源动力,培育发展新质生产力的新动能。

基于联合方向梯度和均值对比度的红外弱小目标检测方法

针对小目标在整幅图像中占比很低,且目标周围存在大量杂波,提出了一种基于联合方向梯度(Associated Directional Gradient,ADG)和均值对比度(Mean Contrast,MC)的红外弱小目标检测算法。该算法由两个模块组成:ADG利用红外弱小目标的高斯分布模型,将单一方向的梯度与一个相邻方向上的梯度相加组成新的联合梯度特征,增强真实目标、抑制背景杂波的同时能够消除高亮边缘对目标检测效果的影响;MC融入方向信息来计算目标的多方向对比度,选用多方向对比度的最小值抑制结构噪声,并将均值滤波的思想引入对比度的计算,抑制背景中的孤立噪声,进一步降低检测的虚警率。在实际红外图像上的实验结果表明,该算法在增强目标信噪比和抑制背景噪声方面,能够取得较好效果。

基于重叠网格的船舶航向稳定性数值研究

基于重叠网格技术,采用URANS粘性数值模拟方法,对标准船模KVLCC2裸船体的航向稳定性进行了数值预报。基于STAR-CCM+平台,采用重叠网格技术和切割体网格,根据SIMMAN2014提供的标准算例,对KVLCC2进行了斜航运动和纯艏摇运动的数值模拟,得到了横向力和转首力矩的历时曲线,并根据操纵性数学模型推倒出水动力导数,并计算稳定性衡准数,所有计算结果同模型试验数据吻合较好,验证了采用当前处理方法预报航向稳定性的可靠性。

高压直流输电保护定值整定依据及配合关系探讨

在中国30余年的高压直流输电工程实践中形成了一套高压直流输电保护系统定值体系。文中结合近年来在应用中出现的复杂案例,对以下保护的定值整定依据开展了进一步探讨:阀短路保护启动定值需避开与换流阀并联的阻容回路的充电电流;换流器过流保护过负荷段定值整定依据是直流控制系统失控造成直流运行电流超过控制的过负荷目标值,以及控制目标电流超过所设定的运行时间;直流低电压保护阈值及延时定值的整定需兼顾保护的后备功能,不确保与换相失败保护双桥原理长延时段配合。另外,深入探讨了交直流系统间、金属回线运行方式下直流保护间,以及高压线路再启动与低压再启动间的定值配合问题。最后,提出了高压直流输电保护系统的定值及定值间的配合应有一定的规范性和适度的灵活性的建议。

基于原型对比学习的开放集识别方法

开放集识别的目标是识别出未知类样本,同时保持对已知类样本的分类能力.现有的判别式开放集识别方法忽视了已知类过度占用特征空间和模型训练过程缺乏未知类信息的问题,导致未知类样本容易被误分类为已知类.为此,提出一种结合原型对比学习的开放集识别方法.引入对比学习和类原型理论,使用编码器和投影网络对开放集识别问题进行建模,设计原型对比损失函数,使用梯度下降法学习模型参数,最小化样本与其对应的类原型之间的距离和最大化样本与其他类原型间的距离,促使样本在特征空间中向类原型靠近,从而缓解已知类过度占用特征空间的问题.此外,设计混合样本对比损失函数,提出样本生成方法OSR-Mix以生成未知类样本,从而在模型训练过程有效地补充未知类信息.在4个公开数据集上的实验结果表明,与主流的开放集识别方法相比,本文提出的方法在AUROC和F1分数上均有明显的优势.

集值映射的Michel-Penot方向导数与Michel-Penot次微分

采用标量化方法,研究集值映射的方向导数和次微分.借助Gerstewizt函数,给出了集值映射的Michel-Penot方向导数和Michel-Penot次微分的概念,研究了它们的性质,建立了它们的计算法则,并利用Michel-Penot次微分给出了无约束集值优化问题的优化条件.

中英高等教育管理体系构建方向的差异性对比研究

随着国际、国内环境的不断变化和高等教育管理内部模式的不完善,高等教育管理体系弊病丛生,羁绊高等教育的发展。该文通过中英高等教育管理体系建构方向的差异性对比,拟从中找出值得借鉴的教育管理方法。通过对比分析发现,中国高等教育管理体系在社会教育资源管理、课程设置合理性评价、教育模式的时代适应性方面存在发展优势,同时发现英国高等教育管理体系中的个性化、人性化、开放性发展理念的意义与价值。当今时代,我国高等教育管理需要进一步创新,以适应不断变化的时代发展;体系需要进一步完备,不断满足师生的各种需求。若能将英国高等教育管理体系中的自由、民主、个性化、人本化、开放性和时效性等理念融入其中,将对中国高等教育管理体系的深层次优化产生积极的影响。

基于改进粗糙集的低照度遥感图像对比度增强方法

为解决图像增强后存在的噪声问题,文章提出基于改进粗糙集的低照度遥感图像对比度增强方法。该方法先基于改进粗糙集进行低照度遥感图像预处理,后自适应调整低照度遥感图像,采用提高饱和度、恢复色彩等操作,完成对图像的对比度增强处理。实验结果表明,文章所提方法的应用使图像的对比度指标得到了显著提升,应用效果更优。

不同发酵方式对酸豇豆品质的影响

以新鲜豇豆为原料,采用自然发酵(CK组)、接种商业菌种(CS组)、接种自筛直投式菌剂(DVS组)3种方式发酵豇豆,测定发酵过程中发酵液的总酸、pH值及发酵成熟后豇豆的盐度、亚硝酸盐、氨基酸态氮、游离氨基酸、乳酸菌数、色差、感官品质、质构特性,分析发酵方式对酸豇豆品质的影响。结果表明,在发酵过程中,DVS组的总酸增长速度最快,在1~6 d均高于CS组、CK组;CS组、DVS组的pH值下降速率比CK组快,在7 d时CS组p H值最低,DVS组仅次于CS组;在发酵至第7天时,DVS组菌落总数分别比CK组、CS组高33.86%、42.31%。发酵成熟后,DVS组的盐度、亚硝酸盐、b^(*)值最低,氨基酸态氮、游离氨基酸、乳酸菌数、感官评分、硬度、粘力、胶着性、咀嚼性最高,L^(*)值、a^(*)值、弹性与其他发酵方式无显著性差异(P>0.05)。综合可知,DVS组不仅发酵启动快,且酸豇豆成品的综合品质更优。

直投式酵母菌发酵对江蓠腥味及膳食纤维性质的影响

海藻是重要的海洋生物资源,富含多种生物学功能的膳食纤维。传统工艺制备的海藻膳食纤维具有较强的腥味,影响其在食品中的应用。以江蓠为原料,研究直投式酵母菌发酵对江蓠腥味及其膳食纤维性质的影响。研究表明,优化得到酵母菌直投式发酵剂发酵脱腥的温度为25℃、活化菌液稀释倍数为4、江蓠与稀释菌液比例为1∶20(g/mL)、发酵时间为4 h。发酵后,江蓠样品的腥味强度评分由2.28上升至9.67,腥味成分中的正己醛、1-辛烯-3-醇、(Z)-4-癸烯醛、(Z),(Z)-2,4-癸二烯醛含量明显下降。发酵前后,江蓠膳食纤维的持水性分别为29.20、30.50g/g、持油性分别为5.73、6.09 g/g、白度分别为1.86%和1.77%、凝胶强度分别为355、463 N·mm。综上,江蓠进行直投酵母菌发酵后,能较好地降低其腥味,且对江蓠膳食纤维的性质影响较小。

TABLE BASED METHOD FOR COMPETENCE SET EXPANSION

Each directed graph with the asymmetric costs defined over its arcs,can be represented by a table,which we call an expansion table.The basic properties of cycles and spanning tables of the expansion table corresponding to the cycles and spanning trees of the directed graph is first explored.An algorithm is then derived to find a minimum spanning table corresponding to a minimum spanning tree in the directed graph.Finally,how to use the algorithm to find the optimal expansion of competence set and related problems are discussed.