Balancing large systems of national accounts

Systems of national accounts typically contain measurement errors. Official statisticians are prepared to give initial estimates with subjective information on the standard deviations of the measurement errors of these estimates. The systems should satisfy certain accountaing identities, that is, the total incomings into any account should match the total outgoings of the account. A least-squares procedure for the adjustment of large systems of national accounts is proposed, which adjusts the initial estimates so that they satisfy the accounting restrictions. The computational requirements of this adjustment procedure are enormous as the systems of national accounts are frequently very large. Hence, the problem is reformulated and a conjugate gradient algorithm which exploits the constraint sparcity and the specific structure of economic accounting matrices is proposed. The associated computer program is self-contained, relatively cheap, and has been applied to systems of up to 262 accounts.     

Algorithmic Debugging and Hypothetical Reasoning

This paper presents a generalization of Shapiro style algorithmic debugging for generalized Horn clause intuitionistic logic. This logic offers hypothetical reasoning and negation is defined not by failure but by inconsistency. We extend Shapiro's notion of intended interpretation, symptoms and errors and give formal results paralleling those known for definite clauses. We also show how a corresponding diagnosis module for RISC- a logic programming system for generalized Horn clause intuitionistic logic-can be defined by meta interpretation. In contrast to Shapiro's PROLOG modules ours work independently of the specific computation rule that in RISC may be specified by the user.     

一种锂电池多模组联合均衡系统的设计

车用动力电池组在充放电循环使用中容易出现一致性恶化的现象,这会导致电池容量衰减甚至引发安全问题。为了解决此问题,文中提出了一种基于CAN网络的锂电池多模组联合均衡系统。该系统能够级联多个均衡器,每个均衡器能够利用充电芯片对电池模组进行主动均衡,同时结合小电阻阵列进行被动均衡,并利用串联在均衡器外部的大功率电阻为电池模组提供快速放电均衡。通过设计有效的控制策略与均衡算法,实现了多个模组联合均衡的目的。仿真和实验对控制策略与均衡算法进行了验证,在实验中,电池组电压极差从均衡前的200 mV缩小为均衡后的20 mV,证明该均衡系统可以有效改善电池组的一致性情况。     

Improving quality of software product line by analysing inconsistencies in feature models using an ontological rule‐based approach

In software product line engineering, feature models (FMs) represent the variability and commonality of a family of software products. The development of FMs may introduce inaccurate feature relationships. These relationships may cause various types of defects such as inconsistencies, which deteriorate the quality of software products. Several researchers have worked on the identification of defects due to inconsistency in FMs, but only a few of them have explained their causes. In this paper, FM is transformed to predicate‐based feature model ontology using Prolog. Further, first‐order logic is employed for defining rules to identify defects due to inconsistency, the explanations for their causes, and suggestions for their corrections. The proposed approach is explained using an FM available in Software Product Line Online Tools repository. It is validated using 26 FMs of discrete sizes up to 5,543 features, generated using the FeatureIDE tool and real‐world FMs. Results indicate that the proposed methodology is effective, accurate, and scalable and improves software product line.     

热拌沥青混合料四点弯曲梁疲劳试验结果的不一致性及修正

设计了室内试验,对相同频率、相同应变、相同温度条件下的HMA试件在ASTM D7460和AASHTO T321两种规范下的四点弯曲梁疲劳试验结果进行了对比,发现存在较大的不一致性;从HMA的粘弹特性以及两种规范下的输入应变和输入荷载在试验中的实际响应出发,分析了实验结果出现不一致性的原因,即输入应变和实际应变的不一致导致了试验结果的不一致;提出了一种简便而有效的修正方法并进行了验证。研究结果有助于缩小在ASTM D7460和AASHTO T321两种规范下,同种HMA、相同试验条件得出的疲劳结果的不一致性,为路面设计、施工提供更加客观、准确的数据支撑。     

基于能观测性分析的机器人EKF-SLAM算法

针对传统EKF-SLAM算法中存在状态估计不一致的问题,从系统能观测性角度分析,提出一种增加观测性约束条件的算法,利用补偿矩阵U最优化求解约束条件,得到新的线性点,并通过优化系统的雅克比矩阵重构系统能观测矩阵,使得EKF-SLAM系统与非线性SLAM系统观测方程能观矩阵的秩保持一致.结果表明,所提出算法在状态估计的精确性和协方差一致性方面明显优于传统的EKF-SLAM算法,研究工作和结论对车辆自主驾驶有一定的参考价值.     

一种基于操作增量的分布式系统悔改方法

悔改技术是解决系统失效问题的途径,是保证系统和数据安全的有效手段.针对操作失误在系统失效诱因中的比重日益增大的问题,提出并实现了一种基于操作增量的分层悔改方法.首先,采用形式化描述语言对基于操作增量的悔改相关概念进行定义与规约;在此基础上,建立了一种分布式系统分层悔改模型,给出了操作增量的构建方法以及对错误操作的修复方法,并利用分级补偿策略解决悔改恢复过程可能出现的不一致性问题.实验结果表明,基于操作增量的悔改恢复方法与传统的卷回恢复方法相比,减小了恢复粒度、降低了恢复所需系统开销、提高了恢复速度,体现了更高的恢复效率.     

对贯标工作“两张皮”的探讨

作者通过对十多年贯标工作实践的总结和思考,认为贯标工作脱离实际、认证结果名不符实是其主要的弊病。本文通过对“两张皮”现象的原因分析,理出一条清除“两张皮”的思路,并在实际工作中进行尝试,取得点滴成效。希望通过本文与有识之士进行再探索,为贯标认证的真实有效,做点实际工作。