Side-Channel Analysis for the Authentication Protocols of CDMA Cellular Networks

Time-division multiple access (TDMA) and code-division multiple access (CDMA) are two technologies used in digital cellular networks. The authentication protocols of TDMA networks have been proven to be vulnerable to side-channel analysis (SCA), giving rise to a series of powerful SCA-based attacks against unprotected subscriber identity module (SIM) cards. CDMA networks have two authentication protocols, cellular authentication and voice encryption (CAVE) based authentication protocol and authentication and key agreement (AKA) based authentication protocol, which are used in different phases of the networks. However, there has been no SCA attack for these two protocols so far. In this paper, in order to figure out if the authentication protocols of CDMA networks are sufficiently secure against SCA, we investigate the two existing protocols and their cryptographic algorithms. We find the side-channel weaknesses of the two protocols when they are implemented on embedded systems. Based on these weaknesses, we propose specific attack strategies to recover their authentication keys for the two protocols, respectively. We verify our strategies on an 8-bit microcontroller and a real-world SIM card, showing that the authentication keys can be fully recovered within a few minutes with a limited number of power measurements. The successful experiments demonstrate the correctness and the effectiveness of our proposed strategies and prove that the unprotected implementations of the authentication protocols of CDMA networks cannot resist SCA.     

差异分布式存储系统应急资源优化调度仿真

针对当前存储系统应急资源调度方法存在的调度可靠性较低、实时性较差等问题,提出一种基于差异分布式存储系统的应急资源优化调度方法,利用属性信息划分应急资源样本集合,计算应急资源信息增益量和信息增益率,创建一个基于线性组合的综合变量,获取综合变量的方差,引入拉格朗日算法对应急资源做预处理操作,得出最佳的应急资源,并提取最佳应急资源的特征,完成对存储系统应急资源特征的提取。针对资源需求点所需的应急资源,利用不断靠近个体和群体历史最优两个位置,找出最优位置,将量子引入到粒子群优化算法中,更新粒子群,找到应急资源特征的最优分配方案,将方案对应的特征整合起来,找出与其相对的应急资源,实现对差异分布式存储系统应急资源的优化调度。仿真结果表明,所提方法的应急资源调度准确率高达99.99%,说明所提调度方法可以快速、可靠地调度存储系统中的应急资源。     

Probabilistic cost prediction for submarine power cable projects

It is estimated that Europe alone will need to add over 250,000 km of transmission capacity by 2050, if it is to meet renewable energy production goals while maintaining security of supply. Estimating the cost of new transmission infrastructure is difficult, but it is crucial to predict these costs as accurately as possible, given their importance to the energy transition. Transmission capacity expansion plans are often founded on optimistic projections of expansion costs. We present probabilistic predictive models of the cost of submarine power cables, which can be used by policymakers, industry, and academia to better approximate the true cost of transmission expansion plans. The models are both generalizable and well-specified for a variety of submarine applications, across a variety of regions. The best performing statistical learning model has slightly more predictive power than a simpler, linear econometric model. The specific decision context will determine whether the extra data gathering effort for the statistical learning model is worth the additional precision. A case study illustrates that incorporating the uncertainty associated with the cost prediction to calculate risk metrics - value-at-risk and conditional-value-at-risk - provides useful information to the decision-maker about cost variability and extremes.     

Hemodialysis‐induced bradycardia, “a plumbing issue”: Resolved with catheter repositioning

Sudden cardiac death (SCD) is reported as leading cause of death in patients on chronic hemodialysis. Arrhythmias are proposed to be a major predisposing factor for SCD. However, triggers for potentially lethal arrhythmias are not well understood. Here we describe a case of 72‐year‐old man on chronic hemodialysis via permanent Central venous catheter (CVC) who was admitted for evaluation after unwitnessed fall. Within 10 minutes of his first routine dialysis session in the hospital, he had cardiac‐arrest. He was successfully resuscitated within 3 minutes. The next day, fifteen minutes into the dialysis session, he had bradycardia with telemetry demonstrating long sinus pause and he lost consciousness. After few minutes of Advanced Cardiac Life Support (ACLS) he regained pulse and consciousness. Further review of the chest X‐ray revealed the tip of CVC to be directly touching the distal Superior Vena Cava (SVC) wall. We felt the catheter tip may have migrated after the fall and now is irritating the Sinoatrial node and triggering bradyarrhythmia. Next day, the CVC was exchanged, and the tip was placed higher up in superior vena‐cava. After repositioning, we started him on dialysis under intensive monitoring, and he tolerated well without any arrhythmia. Subsequent dialysis was uneventful. We describe a case of recurrent symptomatic intra‐dialytic bradycardia due to abnormal positioning of CVC that resolved after the repositioning of the catheter. This case in addition to similar case in nondialysis settlings provides additional insights into mechanisms of fatal arrhythmias in hemodialysis patient having CVC.     

深基坑工程的风险分析

由于勘察设计的局限性、施工过程中安全意识差、交叉施工等特点,深基坑工程存在地质条件、环境条件、设计方案、施工质量等风险源。深基坑风险分析是对风险的危害性进行系统识别和评估,为施工决策提供依据。     

RBAC系统的权限泄漏问题及分析方法

分析访问控制系统是否存在权限泄漏是评定访问控制系统安全的关键。由此,首先讨论了基于角色的访问控制系统中管理权限的信任委派关系,明确了权限泄漏的定义和基于角色的访问控制系统安全分析的基本含义,形式化描述了两类安全分析实例。然后,运用智能规划技术进行了基于角色的访问控制系统的安全分析,描述了安全分析实例的规划领域模型和规划问题系列的构建过程和规则,设计了相应的安全分析算法,并对分析过程进行了示例说明。     

发展循环经济实施企业可持续发展

本文阐述了循环经济、清洁生产和资源综合利用的内涵及其之间的关系,以广州石化多年来开展清洁生产审核和资源综合利用工作,发展循环经济所取得的成效为例,验证了以清洁生产和资源综合利用技术为手段,发展循环经济是企业实施可持续发展的必由之路。     

基于神经网络的UTRAN网络质量综合评价

为了评价3G无线网络UTRAN的运行质量,给出了3G无线网络UTRAN质量用户感知关键指标, 提出了利用基于前向单隐层BP神经网络方法的UTRAN网络质量综合评价模型. 该模型采用模糊综合评价算法构造训练样本集. 对比模糊综合评价算法对3G试验测试数据和该模型的评价结果可以看出,该模型能稳定、一致、可重复地评价UTRAN网络质量.     

小球藻对奶牛场沼液处理能力及生物质生产的探究

为资源化处理奶牛场沼液、探究小球藻Chlorella vulgaris NIES-227对奶牛场沼液的处理能力以及生物质利用潜力,在柱式光生物反应器中利用小球藻处理沼液占比分别为25%、50%、75%和 100% 4种不同浓度的未灭菌污水。研究结果显示,各浓度污水中总氮、总磷和COD的去除率分别为36.0%～92.5%、42.8%～100%和6.9%～32.2%。在沼液占比为25%的污水中氮磷的去除率最高,氨氮、总氮和总磷的去除效率分别可达99.9%、91.0%和100%。微藻在低浓度沼液（25%～50%）中生长状态良好,在沼液占比为50%的污水中可获得最高生物质产率393.6 mg/(L·d)。但是在高浓度沼液（75%～100%）中微藻生长受到一定抑制,导致氮磷的去除效果变差。培养期间细菌的数量增长显著,促进了COD的去除。各浓度沼液生物质中总脂、总糖和蛋白质含量分别为13.2%～32.2%、12.3%～27.6%和16.2%～30.9%。实验数据表明,低浓度沼液能产生更多高能量组分的生物质,适合用作生物燃料的开发;高浓度沼液能产生含较多蛋白质的生物质,更适合用作动物饲料。     

基于微藻培养的沼液处理相关耦合技术进展

基于微藻培养的沼液处理相关耦合技术是近些年沼液资源化处理利用领域的研究热点。本文综述了沼液处理与CO₂固定耦合技术、沼液处理与高值生物质生产耦合技术、沼液处理与生态农业耦合技术等耦合技术的研究发展现状与优缺点，并指出了各耦合技术发展的关键问题，如沼液处理与CO₂固定耦合技术中高CO₂耐受性藻株选育与固碳影响机理研究问题、沼液处理与高值生物质生产耦合技术中低成本、低能耗高值生物质生产技术开发问题、沼液处理与生态农业耦合技术系统性评价体系缺乏问题等。最后，为促进耦合技术突破现有瓶颈，从微藻选育、微藻培养、沼液处理与沼气工程综合经济性4个角度提出相关的建议。