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Analyzing Ethereum Smart Contract Vulnerabilities at Scale Based on Inter-Contract Dependency

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Computer Modeling in Engineering & Sciences 2023年第5期135卷 1625-1647页

作者： Qiuyun Lyu Chenhao Ma yanzhao shen Shaopeng Jiao Yipeng Sun Liqin Hu School of Cyberspace Hangzhou Dianzi UniversityHangzhou310018China Research and Development Department Shandong Institute of BlockchainJinan250102China Security Team Shanghai Anshi Network TechnologyLtd.Shanghai200233China

Smart contracts running on public blockchains are permissionless and decentralized,attracting both developers and malicious ***,the world’s largest decentralized application platform on which more than 40 million smart contracts are running,is frequently challenged by smart contract ***’s worse,since the homogeneity of a wide range of smart contracts and the increase in inter-contract dependencies,a vulnerability in a certain smart contract could affect a large number of other contracts in ***,little is known about how vulnerable contracts affect other on-chain contracts and which contracts can be ***,we first present the contract dependency graph(CDG)to perform a vulnerability analysis for Ethereum smart contracts,where CDG characterizes inter-contract dependencies formed by DELEGATECALL-type internal transaction in ***,three generic definitions of security violations against CDG are given for finding respective potential victim contracts affected by different types of vulnerable ***,we construct the CDG with 195,247 smart contracts active in the latest blocks of the Ethereum and verify the above security violations against CDG by detecting three representative known *** to previous large-scale vulnerability analysis,our analysis scheme marks potential victim contracts that can be affected by different types of vulnerable contracts,and identify their possible risks based on the type of security violation actually *** analysis results show that the proportion of potential victim contracts reaches 14.7%,far more than that of corresponding vulnerable contracts(less than 0.02%)in CDG.

关键词： Smart contract vulnerability smart contract homogeneity contract dependency graph automated analysis

Research Development and Perspective on Slow Slip, Tremors, and Slow Earthquakes

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Earthquake Research in China 2007年第4期21卷 355-364页

作者： Wang yanzhao shen Zhengkang State Key Laboratory of Earthquake Dynamics Institute of Geology CEA Beijing 100029 China

Seismological and geodetic observations indicate that slow slip sometimes occurs in active fault zones beneath the seismogenic depth, and large slow slip can result in transient ground motion. Slow earthquakes, on the other hand, emit tremor-like signals within a narrow frequency band, and usually produce no catastrophic consequences. In general, slow slip and slow earthquakes probably correspond to deformation processes associated with releasing elastic energy in fault zones, and understanding their mechanisms may help improve our understanding of fault zone dynamic processes. This article reviews the research progress on slow slip and slow earthquakes over the last decade. Crustal motion and tremor activities associated with slow slip and slow earthquakes have been investigated extensively, mainly involving locating sources of slow slip and slow earthquakes and numerical modeling of their processes. In the meantime, debates have continued about slow slip and slow earthquakes, such as their origins, relationship, and mechanisms.

关键词： GPS observations Slow earthquake Slow slip Tremor Earthquake prediction

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一种开关电流型的ΣΔ调制器

清华大学学报（自然科学版） 1999年第S1期39卷 101-104页

作者：许刚沈延钊清华大学微电子研究所

为了推广开关电流电路技术（ＳＩ）的应用，引用了新型的两步采样开关电流技术（Ｓ２Ｉ），对该电路中减小时钟馈漏效应的几种方法进行了分析。利用差分平衡结构的Ｓ２Ｉ存储单元设计了平衡Ｓ２Ｉ积分器，并在此基础上设计出一种平衡差... 详细信息

为了推广开关电流电路技术（ＳＩ）的应用，引用了新型的两步采样开关电流技术（Ｓ２Ｉ），对该电路中减小时钟馈漏效应的几种方法进行了分析。利用差分平衡结构的Ｓ２Ｉ存储单元设计了平衡Ｓ２Ｉ积分器，并在此基础上设计出一种平衡差分结构的二阶ΣΔ调制器。该调制器能够完全与标准ＣＭＯＳ数字工艺兼容。利用标准１．２μｍ数字ＣＭＯＳ工艺的ＨＳＰＩＣＥ模型参数进行模拟，并用ＭＡＴＬＡＢ对ＨＳＰＩＣＥ输出结果进行了分析，验证了ΣΔ调制器的功能。

关键词：开关电流两步采样开关电流技术(S2I) ΣΔ调制器

A 5V 8b 40MSample/s Pipelined Analog-to-Digital Converter

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A 5V 8b 40MSample/s Pipelined Analog-to-Digital Converter

2004 7th International Conference on Solid-State and Integrated Circuits Technology（ICSICT 2004）

作者： Xue Liang shen yanzhao Zhang Xiangmin Institute of Microelectronics Tsinghua University Beijing 100084 China

＜正＞In this paper,a 5V 8b 40Msamp les/s pipelined A/D converter is *** A/D converter contains seven stages and each stage realizes a resolution of *** reduce both linear and nonlinear errors,bottom-plate sampling,bootstrap and digital correction techniques are applied in ADC *** clocks are necessary for those *** results are obtained,with 1MHz input signal,the ADC acquired SNDR of 48.2dB,SFDR of 58.2dB and 7.8 *** chip is fabricated in 0.35 m N-well CMOS technology and occupies an area of 4 mm2.

关键词： A/D Pipelined Bootstrap Bottom-Plate Sampling

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一种低功耗扩展计数型模数变换器设计

固体电子学研究与进展 2012年第4期32卷 386-391页

作者：陈宏雷伍冬沈延钊许军清华大学微电子学研究所北京100084

扩展计数型模数变换器(ADC)结合了ΣΔ调制器高精度和Nyquist速率ADC速度相对较快的优点,因而获得了广泛的重视。设计了一种13bit的扩展计数型ADC,设计中采用了1.5bit量化技术和硬件复用技术,其中,1.5bit量化技术降低了系统对比较器精... 详细信息

扩展计数型模数变换器(ADC)结合了ΣΔ调制器高精度和Nyquist速率ADC速度相对较快的优点,因而获得了广泛的重视。设计了一种13bit的扩展计数型ADC,设计中采用了1.5bit量化技术和硬件复用技术,其中,1.5bit量化技术降低了系统对比较器精度的要求,因而可使用动态比较器来降低系统的功耗。硬件复用技术利用了扩展计数型ADC两步变换分时操作的特点,采用同一套模拟器件实现了两个变换过程,既降低了系统功耗,又减小了核心电路的面积。上述设计采用0.18μm CMOS混合信号工艺流片验证,芯片核心部分的面积只有0.06mm2。测试结果表明该ADC的有效位数(ENOB)为10.6bit,在19.5ks/s的转换频率下功耗只有115μW。

关键词：扩展计数型模数变换 ΣΔ调制器硬件复用

Transient Characteristics and Accommodative Current Limiting Strategy for Bidirectional Interlinking Converters in Hybrid AC/DC Microgrids

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CSEE Journal of Power and Energy Systems 2024年第4期10卷 1575-1588页

作者： Xia shen Zhikang Shuai Wen Huang Chao shen Yang shen Z.John shen College of Electrical and Information Engineering Hunan UniversityChangsha 410082China Department of Electrical and Computer Engineering Illinois Institute of TechnologyChicagoIL 60616 USA

Bidirectional interlinking converter(BIC)is the core equipment in a hybrid AC/DC microgrid connected between AC and DC ***,the variety of control modes and flexible bidirectional power flow complicate the influence of AC faults on BIC itself and on DC sub-grid,which potentially threaten both converter safety and system *** study first investigates AC fault influence on the BIC and DC bus voltage under different BIC control modes and different pre-fault operation states,by developing a mathematical model and equivalent sequence ***,based on the analysis results,a general accommodative current limiting strategy is proposed for BIC without limitations to specific mode or operation *** amplitude is predicted and constrained according to the critical requirements to protect the BIC and relieving the AC fault influence on the DC bus *** with conventional methods,potential current limit failure and distortions under asymmetric faults can also be ***,experiments verify feasibility of the proposed method.

关键词： Bidirectional interlinking converter current limiting fault characteristic hybrid AC/DC microgrid variation/oscillation of DC bus voltage

Rational Solutions of First Order Algebraic Ordinary Differential Equations

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Journal of Systems Science & Complexity 2024年第2期37卷 567-580页

作者： FENG Shuang shen Liyong School of Physical and Mathematical Sciences Nanjing Tech UniversityNanjing 211816China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China

Let f(t,y,y')=∑ _(i=0)^(n )a_(i)(t,y)y'^(i)=0 be an irreducible first order ordinary differential equation with polynomial *** in 1998 proved that there exists a constant C such that every rational solution of f(t,y,y')=0 is of degree not greater than *** show that this degree bound C depends not only on the degrees of f in t,y,y' but also on the coefficients of f viewed as the polynomial in t,y,y'.In this paper,the authors show that if f satisfies deg(f,y)0,then the degree bound C only depends on the degrees of f in t,y,y',and furthermore we present an explicit expression for C in terms of the degrees of f in t,y,y'.

关键词： Degree bound first order AODE height rational solution

Influence of erosion voids and traffic loads on buried large-diameter reinforced concrete pipes

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Underground Space 2024年第4期17卷 120-131页

作者： Ming Xu Dawei shen Department of Civil Engineering Tsinghua UniversityBeijing 100084China Beijing Institute of Technology Beijing 100081China

Geotechnical centrifuge tests were conducted to examine the influence of invert voids and surface traffic loads on 1400 mm diameter reinforced concrete pipes buried with a shallow soil cover depth of 700 *** formation beneath the pipe was simulated during centrifuge *** test results revealed that before void formation,the surface load directly above the middle of the pipe caused a significant increase in not only the circumferential bending moments but also the longitudinal bending moments,the latter of which was considerable and could not be *** formation beneath the middle of the pipe led to a reduction in both the circumferential bending moments and longitudinal bending moments at all measuring positions,i.e.,crown,springline,and *** most significant reduction occurred at the invert,and there was even a reversal in the sign of the invert longitudinal bending moment.A comparison was made between centrifuge tests with erosion voids and surface loads at different horizontal positions,which had a marked influence even when the positions differed by half a pipe *** rotation played an important role in relieving large bending moments of pipe barrels in a jointed pipeline when the void and surface load were located at the joint.

关键词： Centrifuge test Erosion void Reinforced concrete pipe Traffic loading Longitudinal bending moment Joint rotation

Large reversible magnetocaloric effect in antiferromagnetic Er_(3)Si_(2)C_(2) compound

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Journal of Rare Earths 2024年第8期42卷 1555-1559,I0005页

作者： Hao Sun Lu Tian Xinqiang Gao Zhaojun Mo Jun shen Baogen shen School of Rare Earths University of Science and Technology of ChinaHefei230026China Ganjiang Innovation Academy Chinese Academy of SciencesGanzhou341000China Department of Energy and Power Engineering School of Mechanical EngineeringBeijing Institute of TechnologyBeijing100081China

The magnetic properties,magnetic phase transition and magnetocaloric effects(MCE) of Er_(3)Si_(2)C_(2) compound were investigated based on theoretical calculations and experimental *** on the first principles calculations,the antiferromagnetic(AFM) ground state type in Er_(3)Si_(2)C_(2) compound was predicted and its electronic structure was *** experimental results show that Ei_(3)Si_(2)C_(2) compound is an AFM compound with the Neel temperature(T_(N) of 7 K and undergoes a field-induced firstorder magnetic phase transition from AFM to ferromagnetic(FM) under magnetic fields exceeding 0.6 T at 2 *** magnetic transition process of Er_(3)Si_(2)C_(2) compound was investigated and *** values of the maximum magnetic entropy change(-ΔS_(M)^(max)) and the refrigeration capacity(RC) are 17 J/(kg·K)and 193 J/kg under changing magnetic fields of 0-5 T,*** a potential cryogenic magnetic refrigerant,the Er_(3)Si_(2)C_(2) compound also provides an interesting research medium to study the magnetic phase transition process.

关键词： Magnetic materials Magnetocaloric Metamagnetic transitions Magnetic phase transition Rare earths