Construction of a control system for disturbance rejection using a dual observer

A well‐known control system which can reduce the adverse effects of disturbances is a disturbance observer. However, in many cases of mechanical systems, system disturbances which do not satisfy the matching condition may be imposed. Therefore, it may be difficult to reduce the adverse effects of the disturbances by the traditional disturbance observer. In this paper, a method of control system synthesis for disturbance rejection using a dual observer is proposed. This method is based on the zeroing induced by the disturbance localization problem. This problem may be solved by dividing the state space into observable subspace and unobservable subspace. As compared with an H_∞ controller based on perfect observation, the usefulness of the proposed control system for disturbance rejection is demonstrated by numerical simulations for a two‐mass spring system. © 2002 Scripta Technica, Electr Eng Jpn, 138(4): 50–60, 2002; DOI 10.1002/eej.1138     

Lubricating behavior of iron rhenate and its relation to matching pairs

The iron rhenate was compounded by chemical method, which may be generated during wear process of Fe-Re alloys at elevated temperature. The friction coefficient of iron rhenate has been determined by a pin-on-disc device. The results show that iron rhenate plays role of lubricating at RT-600 °C. The lubricating behavior is related to the matching pairs. The hardness of the materials of matching pairs, compatibility of iron rhenate with materials of matching pairs and surface roughness of disc affect the lubricating behavior of iron rhenate mostly. The principle of matching pairs is proposed. Project supported by the National Natural Science Foundation of China Synopsis of the first author Xiong Dangsheng. associated professor, born in 1960. Current research fields include high-temperature self-lubricating alloys and tribological properties of material.     

A portable stereo vision system for whole body surface imaging

This paper presents a whole body surface imaging system based on stereo vision technology. We have adopted a compact and economical configuration which involves only four stereo units to image the frontal and rear sides of the body. The success of the system depends on a stereo matching process that can effectively segment the body from the background in addition to recovering sufficient geometric details. For this purpose, we have developed a novel sub-pixel, dense stereo matching algorithm which includes two major phases. In the first phase, the foreground is accurately segmented with the help of a predefined virtual interface in the disparity space image, and a coarse disparity map is generated with block matching. In the second phase, local least squares matching is performed in combination with global optimization within a regularization framework, so as to ensure both accuracy and reliability. Our experimental results show that the system can realistically capture smooth and complete whole body shapes with high accuracy.     

组合式空调系统设计中机组选型方法探讨

对目前组合式空调机组在选型设计及使用中出现的问题进行了分析，运用空气处理设备选型的有关理论和计算方法，对舒适性空调系统中机组选型的一些问题和数据进行了简化和近似处理，提出了能够满足工程设计的要求的简便实用的选型方法。     

出钢顺立案模型在宝钢炼钢厂的应用

从基本概念和程序的具体实现两方面,阐述了出钢顺立案模型的功能、特点以及在生产实践中所取得的效果。     

Using multiple indexes for efficient subsequence matching in time-series databases

A time-series database is a set of data sequences, each of which is a list of changing values of an object in a given period of time. Subsequence matching is an operation that searches for such data subsequences whose changing patterns are similar to a query sequence in a time-series database. This paper addresses a performance issue of time-series subsequence matching. First, we quantitatively examine the performance degradation caused by the window size effect, and then show that the performance of subsequence matching with a single index is not satisfactory in real applications. We claim that index interpolation is a fairly effective tool to solve this problem. Index interpolation performs subsequence matching by selecting the most appropriate one from multiple indexes built on windows of their distinct sizes. For index interpolation, we need to decide the sizes of windows for multiple indexes to be built. In this paper, we solve the problem of selecting optimal window sizes from the perspective of physical database design. Given a set of pairs 〈length, frequency〉 of query sequences to be performed in a target application and a set of window sizes for building multiple indexes, we devise a formula that estimates the overall cost of all the subsequence matchings performed in a target application. By using this formula, we propose an algorithm that determines the optimal window sizes for maximizing the performance of entire subsequence matchings. We formally prove the optimality as well as the effectiveness of the algorithm. Finally, we show the superiority of our approach by performing extensive experiments with a real-life stock data set and a large volume of synthetic data sets.     

混合模式的入侵检测技术研究

针对传统入侵检测所采用模式匹配技术存在的弊端,介绍了协议分析技术在入侵检测中的应用,提出了一种混合模式的入侵检测技术,即混合使用特征匹配模式和协议分析技术,充分发挥两者的长处。研究表明,该模型提高了检测效率,减少了误报和漏报。     

基于免疫否定选择算法的机场航班延误状态检测与实现

把免疫算法中的否定选择算法运用到航班延误状态的诊断检测与预测中,将生物免疫系统机制与机场航班运行机制联系起来,建立了相应的自体集合、检测细胞、抗原信息及它们之间的匹配模型,给出了检测方法。首先根据机场航班运行数据生成航班检测的成熟检测器和记忆检测器,然后用否定选择算法和航班数据对检测器进行训练和改进,最后利用检测器中的信息对机场航班状态分段进行预测,获得每个时段的航班延误状况,为机场有关部门对航班延误应急处理提供决策支持。仿真实验表明,该方法能较准确地预测航班的延误状态,且实时性好。     

二连盆地气测解释失误层原因剖析

以往人们对气测解释评价成功的范例介绍较多,而对解释结论与试油结果不符合的层公开交流甚少。该文通过对气测解释失误层进行梳理,归纳了六条“认识不到位”等技术因素造成的解释失误和三条非技术因素造成的偏高解释,通过六个失败实例分析,总结、反思应吸取的教训,对今后的油气水层解释评价应有一定的借鉴意义。