检索结果-南通市图书馆

Analysis of blockchain protocol against static adversarial miners corrupted by long delay attackers

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2020年第3期63卷 49-63页

作者： Quan YUAN Puwen WEI Keting JIA haiyang xue Key Laboratory of Cryptologic Technology and Information Security Ministry of EducationShandong University Department of Computer Science and Technology Tsinghua University State Key Laboratory of Information Security Institute of Information EngineeringChinese Academy of Sciences Data Assurance and Communication Security Research Center Chinese Academy of Sciences

Bitcoin, which was initially introduced by Nakamoto, is the most disruptive and impactive cryptocurrency. The core Bitcoin technology is the so-called blockchain protocol. In recent years, several studies have focused on rigorous analyses of the security of Nakamoto’s blockchain protocol in an asynchronous network where network delay must be considered. Wei, Yuan, and Zheng investigated the effect of a long delay attack against Nakamoto’s blockchain protocol. However, their proof only holds in the honest miner setting. In this study, we improve Wei, Yuan and Zheng’s result using a stronger model where the adversary can perform long delay attacks and corrupt a certain fraction of the miners. We propose a method to analyze the converge event and demonstrate that the properties of chain growth, common prefix, and chain quality still hold with reasonable parameters in our stronger model.

关键词： blockchain bitcoin random oracle delay consensus protocol

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

小口径组合桩在滑坡抢险中的设计方法探讨

路基工程 2024年第1期 191-197页

作者：薛海洋赵青海姚裕春中铁二院工程集团有限责任公司成都610031

为适应滑坡抢险工程的时效性和安全性,在分析小口径组合桩加固机理的基础上,提出设计流程、计算方法及具体参数取值,并应用于某铁路大临道路工程修建期间诱发的一处滑坡整治工程中,通过监控量测和数值模拟分析,验证该设计方法在抢险工... 详细信息

为适应滑坡抢险工程的时效性和安全性,在分析小口径组合桩加固机理的基础上,提出设计流程、计算方法及具体参数取值,并应用于某铁路大临道路工程修建期间诱发的一处滑坡整治工程中,通过监控量测和数值模拟分析,验证该设计方法在抢险工程中的可行性。工程效果证明,计算方法及具体参数取值较为合理。

关键词：工程滑坡抢险整治措施小口径组合桩设计方法参数取值

Fault Attacks on Hyperelliptic Curve Discrete Logarithm Problem over Finite Fields

在线全文

学校读者我要写书评

暂无评论

China Communications 2012年第11期9卷 150-161页

作者： Wang Mingqiang xue haiyang Zhan Tao School of Mathematics Shandong University Jinan 250100 P. R. China State Key Laboratory of Information Security Institute of Information Engineering Chinese Academy of Sciences Beijing 100864. P. R. China

In this paper, we present two explicit invalid-curve attacks on the genus 2 hyperelliptic curve over a finite field. First, we propose two explicit attack models by injecting a one-bit fault in a given divisor. Then, we discuss the construction of an invalid curve based on the faulted divisor. Our attacks are based on the fact that the Hyperelliptic Curve Scalar Multiplication (HECSM) algorithm does not utilize the curve parameters and We consider three hyperelliptic curves as the attack targets. For curve with security level 186 (in bits), our attack method can get the weakest invalid curve with security level 42 (in bits); there are 93 invalid curves with security level less than 50. We also estimate the theoretical probability of getting a weak hyperelliptic curve whose cardinality is a smooth integer. Finally, we show that the complexity of the fault attack is subexponential if the attacker can freely inject a fault in the input divisor. Cryptosystems based on the genus 2 hyperelliptic curves cannot work against our attack algorithm in practice.

关键词：椭圆曲线离散对数问题攻击模式有限域故障椭圆曲线密码体制超椭圆曲线安全级别攻击算法

Fault attacks on hyperelliptic curve discrete logarithm problem over binary field

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2014年第3期57卷 187-203页

作者： WANG MingQiang xue haiyang ZHAN Tao School of Mathematics Shandong University

In this paper,we present invalid-curve attacks that apply to the hyperelliptic curve scalar multiplication(HECSM)algorithm proposed by Avanzi et al.on the genus 2 hyperelliptic curve over binary field.We observe some new properties of the HECSM.Our attacks are based on these new properties and the observation that the parameters f0and f1of the hyperelliptic curve equation are not utilized for the HECSM.We show that with diferent"values"for curve parameters f0,f1,there exsit cryptographically weak groups in the Koblitz hyperelliptic curve.Also,we compute the theoretical probability of getting a weak Jacobian group of hyperelliptic curve whose cardinality is an smooth integer.

关键词： hyperelliptic curve discrete logarithm binary field genus cryptosystem

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

660MW锅炉水冷壁管道泄漏分析

金属加工（热加工） 2024年第6期 45-49页

作者：杜佼伟李霄吕品正张正华肖世俊薛海洋西安石油大学材料科学与工程学院陕西西安710016 陕西君创智盈能源科技有限公司陕西西安710016

火电厂锅炉材料失效泄漏是机组非计划停运的主要原因之一,导致因材料失效而泄漏的原因错综复杂,但鳍片焊接引起的失效泄漏相对较少。以某电厂660MW机组锅炉侧墙垂直水冷壁泄漏为基础,通过金属材料宏观分析、力学分析、金相检测等方法对... 详细信息

火电厂锅炉材料失效泄漏是机组非计划停运的主要原因之一,导致因材料失效而泄漏的原因错综复杂,但鳍片焊接引起的失效泄漏相对较少。以某电厂660MW机组锅炉侧墙垂直水冷壁泄漏为基础,通过金属材料宏观分析、力学分析、金相检测等方法对失效管道进行试验,并结合现场实际情况分析泄漏原因。试验结果表明:本次管道泄漏为管道鳍片拉裂,裂纹扩展至水冷壁管道,导致管道在高温、高压下爆管泄漏。

关键词：水冷壁鳍片裂纹泄漏分析

Machine learning for predicting fatigue properties of additively manufactured materials

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2024年第4期37卷 1-22页

作者： Min YI Ming xue Peihong CONG Yang SONG haiyang ZHANG Lingfeng WANG Liucheng ZHOU Yinghong LI Wanlin GUO State Key Laboratory of Mechanics and Control for Aerospace Structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China Institute for Frontier Science Nanjing University of Aeronautics and AstronauticsNanjing 210016China College of Aerospace Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China Shenyang Engine Research Institute Shenyang 110015China Liaoning Key Laboratory of Impact Dynamics on Aero Engine Shenyang 110015China Science and Technology on Plasma Dynamics Laboratory Air Force Engineering UniversityXi’an 710038China

Fatigue properties of materials by Additive Manufacturing(AM) depend on many factors such as AM processing parameter, microstructure, residual stress, surface roughness, porosities, post-treatments, etc. Their evaluation inevitably requires these factors combined as many as possible, thus resulting in low efficiency and high cost. In recent years, their assessment by leveraging the power of Machine Learning(ML) has gained increasing attentions. A comprehensive overview on the state-of-the-art progress of applying ML strategies to predict fatigue properties of AM materials, as well as their dependence on AM processing and post-processing parameters such as laser power, scanning speed, layer height, hatch distance, built direction, post-heat temperature,etc., were presented. A few attempts in employing Feedforward Neural Network(FNN), Convolutional Neural Network(CNN), Adaptive Network-Based Fuzzy Inference System(ANFIS), Support Vector Machine(SVM) and Random Forest(RF) to predict fatigue life and RF to predict fatigue crack growth rate are summarized. The ML models for predicting AM materials' fatigue properties are found intrinsically similar to the commonly used ones, but are modified to involve AM features. Finally, an outlook for challenges(i.e., small dataset, multifarious features,overfitting, low interpretability, and unable extension from AM material data to structure life) and potential solutions for the ML prediction of AM materials' fatigue properties is provided.

关键词： Additive manufacturing Machine learning Fatigue life Fatigue crack growth rate Prediction

Experimental study on the segregation of primary silicon from the hypereutectic Al-Si melts in the electromagnetic directional solidification

在线全文

学校读者我要写书评

暂无评论

Experimental study on the segregation of primary silicon fro...

蝇克跳小蜂属1中国新记录种(膜翅目:跳小蜂科)

2014中国功能材料科技与产业高层论坛

作者： haiyang xue Guoqiang Lv Wenhui Ma Xi Yang Daotong Chen Shaoyuan Li Faculty of Metallurgical and Energy Engineering Kunming University of Science and Technology State Key Laboratory of Complex Nonferrous Metal Resources Cleaning Utilization in Yunnan Province Engineering Research Center for Silicon Metallurgy and Silicon Materials of Yunnan Provincial Universities

Solar grade silicon and modified Al-Si alloys are widely used in the world.These two favored materials are expected to obtain by the electromagnetic directional solidification of hypereutectic Al-Simelts.The segregation of hypereutectic Al-Si alloy is feasible with respect to the process of either pull-up or drop-down in electromagnetic directional solidification.To explore the segregation efficiency,experiments have been conducted in a high-frequency induction furnace with different pulling conditions of hypereutectic Al-Si.The results show that the segregation efficiency of dropping-down is higher than that of pulling-up;the slower dropping-down rate lead to higher segregation efficiency in the electromagnetic directional solidification;decreasing the induction current cannot increase the segregation efficiency;increasing the temperature gradient may promote the separation efficiency.A separation mechanism model responsible for the formation of the distribution of primary silicon in the cross-sections is also proposed.Wish to provide theoretical basis for the more efficiency of the segregation of hypereutectic Al-Si melts.

关键词： Solar grade silicon Hypereutectic Al-Si melts Electromagnetic directional solidification Segregation efficiency Separation mechanism

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

南京林业大学学报（自然科学版） 2024年第1期48卷 214-218页

作者：张丞慧祖国浩王海洋薛昊天津农学院园艺园林学院天津300392

【目的】进一步丰富我国及天津市的生物多样性,为跳小蜂科物种的系统发育研究奠定基础。【方法】在天津市天津农学院东校区内开展了跳小蜂的采集工作。利用马来氏网采集昆虫标本,并将其保存于含有无水乙醇的收集瓶中。将采集的昆虫标本... 详细信息

【目的】进一步丰富我国及天津市的生物多样性,为跳小蜂科物种的系统发育研究奠定基础。【方法】在天津市天津农学院东校区内开展了跳小蜂的采集工作。利用马来氏网采集昆虫标本,并将其保存于含有无水乙醇的收集瓶中。将采集的昆虫标本带回实验室后,在体视显微镜下根据其形态学特征分拣出跳小蜂科昆虫标本,对目标昆虫进行解剖,并置于5%(体积分数)NaOH溶液中透明后,利用阿拉伯树胶封片法分别将解剖下来的头、胸腹、触角、前翅、后翅、前足、中足、后足等部位压制成玻片标本。用带刻度的目镜在体视显微镜下对各特征部位进行测量,并对各特征部位拍照。最后,依据小蜂的形态特征进行分类鉴定。【结果】对标本进行鉴定认为是蝇克跳小蜂属1中国新记录种。该种雌蜂体长1.10~1.42 mm,大体黑褐色;翅透明;前足腿节基部和端部、中足腿节黄褐色,中足基节褐色,所有胫节和跗节黄褐色;头部长为宽的83%,额顶宽为头宽的0.37倍,具清晰的载毛刻窝;触角柄节中部膨大,长为最宽处的4倍,各索节均宽大于长,棒节3节,长于各索节长度之和,端部有明显的斜切;上颚3齿,后齿较圆钝;胸部密被刚毛,中胸盾片具鳞形刻纹,小盾片具多边形网纹;前翅长约为宽的2倍,无毛斜带开放;中足胫节距为中足胫节长的1/3,略短于中足基跗节;腹部心形,产卵器略伸出。此外,提供了该种雌性成虫的形态特征图及该属中国已知种雌性检索表。【结论】经鉴定证实,检视标本为中国新记录种——敌扑蝇克跳小蜂(Exoristobia dipterae)。

关键词：小蜂总科跳小蜂科蝇克跳小蜂属寄生蜂生物多样性

在线全文

学校读者我要写书评

暂无评论

工业导爆索自动化生产关键技术的研究

煤矿爆破 2023年第4期41卷 16-19页

作者：薛海洋曲思佳徐翠荣湖北帅力化工有限公司湖北咸宁437300

实现工业导爆索自动化生产可改善索类火工产品生产过程的安全性,降低工人劳动强度,提高索类火工品生产效率。重点介绍采用自动循环贮药-供药传送装置,并采用隔爆与防护门联动技术,使各制索机组和炸药暂存间室互为独立系统,实现导爆索生... 详细信息

实现工业导爆索自动化生产可改善索类火工产品生产过程的安全性,降低工人劳动强度,提高索类火工品生产效率。重点介绍采用自动循环贮药-供药传送装置,并采用隔爆与防护门联动技术,使各制索机组和炸药暂存间室互为独立系统,实现导爆索生产过程中药剂传送和添加操作的自动化、制索机组不停机自动添加药等。试生产结果表明:项目工艺技术及设备均能适用于现有导爆索生产技术改造要求,达到安全、技术、质量及效率等技术经济指标要求。

关键词：工业导爆索药剂传输添加药自动化