Fractional Order ［Proportional Integral］ Controllers Parameters Algorithm Based on the Vector Method

In forensic investigations,it is vital that the authenticity of digital evidence should be ensured. In addition,technical means should be provided to ensure that digital evidence collected cannot be misused for the purpose of perjury. In this paper,we present a method to ensure both authenticity and non-misuse of data extracted from wireless mobile devices. In the method,the device ID and a timestamp become a part of the original data and the Hash function is used to bind the data together. Encryption is applied to the data,which includes the digital evidence,the device ID and the timestamp. Both symmetric and asymmetric encryption systems are employed in the proposed method where a random session key is used to encrypt the data while the public key of the forensic server is used to encrypt the session key to ensure security and efficiency. With the several security mechanisms that we show are supported or can be implemented in wireless mobile devices such as the Android,we can ensure the authenticity and non-misuse of data evidence in digital forensics.     

EMD滤波方法在NMR测井中的应用

核磁共振测井中,回波信号的信噪比对T2谱反演及后续地层解释评价过程有重要影响。基于核磁共振测井信号与噪声的分析,提出了一种采用自适应性较强的经验模态分解（ EMD）算法对核磁共振测井原始数据作消噪处理。结果表明,采用该滤波算法,实验室回波数据信噪比由22 dB提高到46 dB,标准油井回波数据信噪比由11 dB提高到31 dB,反演得到的T2分布更加精确,多次重复测量中孔隙度结果有较高的一致性。     

电子数据取证研究综述

电子数据取证技术是信息安全研究领域的新课题,在安全事件应急响应和打击网络犯罪方面发挥巨大的作用,本文首先就电子数据取证的相关概念和工作特点进行了介绍,然后针对电子数据取证中的取证原则、取证模型、取证流程等核心问题进行了探讨,最后对取证的关键技术和新特点进行概述。     

Effects of Al:Si and (Al + Na):Si ratios on the properties of the international simple glass,part II: Structure

High-alumina containing high-level waste (HLW) will be vitrified at the Waste Treatment Plant at the Hanford Site. The resulting glasses, high in alumina, will have distinct composition-structure-property (C-S-P) relationships compared to previously studied HLW glasses. These C-S-P relationships determine the processability and product durability of glasses and therefore must be understood. The main purpose of this study is to understand the detailed structural changes caused by Al:Si and (Al + Na):Si substitutions in a simplified nuclear waste model glass (ISG, international simple glass) by combining experimental structural characterizations and molecular dynamics (MD) simulations. The structures of these two series of glasses were characterized by neutron total scattering and ²⁷Al, ²³Na, ²⁹Si, and ¹¹B solid-state nuclear magnetic resonance (NMR) spectroscopy. Additionally, MD simulations were used to generate atomistic structural models of the borosilicate glasses and simulation results were validated by the experimental structural data. Short-range (eg, bond distance, coordination number, etc) and medium-range (eg, oxygen speciation, network connectivity, polyhedral linkages) structural features of the borosilicate glasses were systematically investigated as a function of the degree of substitution. The results show that bond distance and coordination number of the cation-oxygen pairs are relatively insensitive to Al:Si and (Al + Na):Si substitutions with the exception of the B-O pair. Additionally, the Al:Si substitution results in an increase in tri-bridging oxygen species, whereas (Al + Na):Si substitution creates nonbridging oxygen species. Charge compensator preferences were found for Si-[NBO] (Na⁺), ^[3]B-[NBO] (Na⁺), ^[4]B (mostly Ca²⁺), ^[4]Al (nearly equally split Na⁺ and Ca²⁺), and ^[6]Zr (mostly Ca²⁺). The network former-BO-network former linkages preferences were also tabulated; Si-O-Al and Al-O-Al were preferred at the expense of lower Si-O-^[3]B and ^[3]B-O-^[3]B linkages. These results provide insights on the structural origins of property changes such as glass-transition temperature caused by the substitutions, providing a basis for future improvements of theoretical and computer simulation models.     

Predicting nepheline precipitation in waste glasses using ternary submixture model and machine learning

Nepheline precipitation in nuclear waste glasses during vitrification can be detrimental due to the negative effect on chemical durability often associated with its formation. Developing models to accurately predict nepheline precipitation from compositions is important for increasing waste loading since existing models can be overly conservative. In this study, an expanded dataset of 955 glasses, including 352 high-level waste glasses, was compiled from literature data. Previously developed submixture models were refitted using the new dataset, where a misclassification rate of 7.8% was achieved. In addition, nine machine learning (ML) algorithms (k-nearest neighbor, Gaussian process regression, artificial neural network, support vector machine, decision tree, etc.) were applied to evaluate their ability to predict nepheline precipitation from glass compositions. Model accuracy, precision, recall/sensitivity, and F1 scores were systemically compared between different ML algorithms and modeling protocols. Model prediction with an accuracy of ~0.9 (misclassification rate of ~10%) was observed for different algorithms under certain protocols. This study evaluated various ML models to predict nepheline precipitation in waste glasses, highlighting the importance of data preparation and modeling protocol, and their effect on model stability and reproducibility. The results provide insights into applying ML to predict glass properties and suggest areas for future research on modeling nepheline precipitation.     

核电工程材料的应力腐蚀破裂研究

采用慢应变速率试验(SSRT)和U型弯曲试验技术研究了水中杂质离子、溶解氧(DO)、外加电位以及温度等对核电工程材料304不锈钢(SS)、316SS以及A533B压力容器用钢在高温水中应力腐蚀破裂(SCC)的影响,并结合电化学测试和表面膜分析结果进行了讨论,还根据304SS的U型弯曲和SSRT结果的差异提出了SCC加速试验的选择原则建议。     

Analysis of failed nuclear plant components

Argonne National Laboratory has conducted analyses of failed components from nuclear power- gener-ating stations since 1974. The considerations involved in working with and analyzing radioactive compo-nents are reviewed here, and the decontamination of these components is discussed. Analyses of four failed components from nuclear plants are then described to illustrate the kinds of failures seen in serv-ice. The failures discussed are (1) intergranular stress- corrosion cracking of core spray injection piping in a boiling water reactor, (2) failure of canopy seal welds in adapter tube assemblies in the control rod drive head of a pressurized water reactor, (3) thermal fatigue of a recirculation pump shaft in a boiling water reactor, and (4) failure of pump seal wear rings by nickel leaching in a boiling water reactor. Work supported by Commonwealth Edison Company under ACK 85026.     

基于Word文档的数据隐藏方法

在分析当前数据隐藏与恢复相关技术研究基础上,参照微软官方最新公布的复合文档存储规范,从利用载体Word文档现有空间中未真正使用部分和适度扩展新空间两条思路出发,设计一种利用Word文档作载体隐藏秘密信息的解决方案,包括在文字、各种嵌入式对象及其相应控制结构数据中隐藏信息。实践表明,隐藏数据后的载体文档可以被正常拷贝和使用电子邮件传送,根据需要隐藏的信息随机选择使用该方案,被隐藏信息更不容易被侦测出来,被二次编辑后被隐藏信息一般不会被破坏,鲁棒性不错,具有一定的实用价值。     

微型核磁共振传感器实时监测汽轮机油老化状态

汽轮机油被广泛应用于火力发电厂汽轮机的调节系统,随着使用年限的增加,其润滑性能和电气性能会随之下降。针对汽轮机油老化状态缺少简单有效的实时监测手段这一问题,提出用核磁共振技术进行检测,并设计了一种方便实时监测的微型核磁共振传感器。传感器尺寸为30 mm ×30 mm ×36 mm,重107 g,可以浸泡在汽轮机油中对其进行检测。通过对来自两个发电厂的不同使用年限的汽轮机油进行测量实验发现：汽轮机油的核磁共振参数有效横向弛豫时间T2ef与纵向弛豫时间T1随着其使用年限的增加而减小。该传感器制作成本低,尺寸微小,操作方便,使得实时监测汽轮机油的老化状态成为一种可能。     

基于闪存冗余块的文件隐藏技术

为保护闪存型存储设备上的敏感文件,提出基于闪存冗余块的文件隐藏方法.该方法在分析Nand型flash特点及FAT32文件系统管理机制的基础上,将闪存中冗余的物理块有机组合以存储敏感文件,并采用与文为保护闪存型存储设备上的敏感文件,提出基于闪存冗余块的文件隐藏方法.该方法在分析Nand型flash特点及FAT32文件系统管理机制的基础上,将闪存中冗余的物理块有机组合以存储敏感文件,并采用与文件隐藏相似的方法恢复原始文件.实验结果表明,基于闪存冗余块的文件隐藏方法不占用闪存有效空间,具有隐蔽性高、鲁棒性强且隐藏容量大的特点,能有效抵抗软件取证攻击.