导弹大扇面发射自动驾驶仪半实物仿真

介绍了某型反舰导弹大扇面(±70°)自动驾驶仪的半实物仿真方案。分析了仿真中碰到的几个技术问题,并提出了解决方法。给出了仿真结果,证明由半实物仿真校验后的数学摸型是十分准确的。     

Building a cascade detector and its applications in automatic target detection

A hierarchical classifier (cascade) is proposed for target detection. In building an optimal cascade we considered three heuristics: (1) use of a frontier-following approximation, (2) controlling error rates, and (3) weighting. Simulations of synthetic data with various underlying distributions were carried out. We found that a weighting heuristic is optimal in terms of both computational complexity and error rates. We initiate a systematic comparison of several potential heuristics that can be utilized in building a hierarchical model. A range of discussions regarding the implications and the promises of cascade architecture as well as of techniques that can be integrated into this framework is provided. The optimum heuristic--weighting algorithms--was applied to an IR data set. It was found that these algorithms outperform some state-of-the-art approaches that utilize the same type of simple classifier.     

A new full-text indexing model with low space overhead for chinese text retrieval

Text retrieval systems require an index to allow efficient retrieval of documents at the cost of some storage overhead. This paper proposes a novel full-text indexing model for Chinese text retrieval based on the concept of adjacency matrix of directed graph. Using this indexing model, on one hand, retrieval systems need to keep only the indexing data, instead of the indexing data and the original text data as the traditional retrieval systems always do. On the other hand, occurrences of index term are identified by labels of the so-called s-strings where the index term appears, rather than by its positions as in traditional indexing models. Consequently, system space cost as a whole can be reduced drastically while retrieval efficiency is maintained satisfactory. Experiments over several real-world Chinese text collections are carried out to demonstrate the effectiveness and efficiency of this model. In addition to Chinese, The proposed indexing model is also effective and efficient for text retrieval of other Oriental languages, such as Japanese and Korean. It is especially useful for digital library application areas where storage resource is very limited (e.g., e-books and CD-based text retrieval systems).     

Spray forming of ultra-fine SiC particle reinforced 5182 Al-Mg

This paper describes the spray forming of SiC particle reinforced Al metal matrix composites (MMCs) with particular emphasis on microstructure characterization of SiC particle distribution. A 5182 Al-Mg alloy was used as matrix material, and SiC particles with a mean diameter of 1.2 m and 2.0 m as reinforcement. The reinforcing particle distribution and microstructural characteristics of MMCs were analyzed in the current study using TEM, SEM and optical microscopy. The distribution of SiC particles in the as-spray deposited and hot-extruded conditions was characterized. SEM results indicate that the SiC particles are homogeneously distributed although some clustering was evident in the matrix. TEM and OM examinations show that most of SiC particles are present intergranularly in the Al matrix. EDS analysis indicated that Mg tends to segregate and form oxide phases in the vicinity of SiC particles and that there is no compositional variation of Mg across grain boundaries in the Al matrix.     

Satisfactory control of discrete-time linear periodic systems

In this paper satisfactory control for discrete-time linear periodic systems is studied. Based on a suitable time-invariant state sampled reformulation, periodic state feedback controller has been designed such that desired requirements of steady state covariance, H-infinity rejection bound and regional pole assignment for the periodic system are met simultaneously. By using satisfactory control theory, the problem of satisfactory periodic controller can be transformed into a linear programming problem subject to a set of linear matrix inequalities （LMIs）, and a feasible designing approach is presented via LMI technique. Numeric example validates the obtained conclusion.     

广义Julia集关于迭代参数的对称性分析

由迭代函数fω,c(z)=zω c(ω∈C,c∈C)构造了广义Julia集(简称广义J集),并通过对迭代函数fω,c(z)=zω c(ω∈C,c∈C)中参数ω,c的改变,根据逃逸时间算法,利用VC 编程得到了相应的广义J集图形.通过图形对比,给出了仅随参数c变化所得图形对称性的一个重要结论,并从理论上给予了证明.类似地,通过对参数ω,c同时变化所得图形的分析,得到了相应的结论.     

唐钢2560m^3高炉炉顶压力的控制

本文主要介绍唐钢2560m3高炉的顶压控制。主要包括顶压减压阀组控制、顶压TRT控制及顶压控制权的切换。     

2,2,2-胺三乙酰-苯胺及其稀土配合物的合成、表征与荧光性质

为了研究三脚架型配体稀土配合物的组成、可能的配位状态及荧光性质,合成了三脚架型配体--2,2,2-胺三乙酰苯胺(L)及其6个稀土配合物.用红外光谱,核磁共振波谱,元素分析,差热-热重,摩尔电导等方法表征了配体及其配合物的组成、配位形式及荧光性质.结果表明,L的化学式为C24H24N4O3,与稀土硝酸盐配位,且n(L):n(Re)=1:1,在DMF中为2:1型电解质,其中,2个NO3-均与金属离子以单齿形式配位;荧光分析表明Tb(Ⅲ)配合物的荧光强度与溶液的pH值有关,并且在中性溶液中荧光强度最大;在分子偶极矩较大的溶剂中,荧光强度最强.说明该配体是较好的稀土荧光敏化剂.     

钛合金表面微弧氧化膜层磨损性能研究

采用微弧氧化技术,以硅酸钠、磷酸钠溶液为电解液,在TC4钛合金表面制备出高硬度、高耐磨的微弧氧化膜层.用扫描电镜观测了膜层的显微结构,用X射线衍射分析其相组成,并对膜层进行了耐磨损和摩擦学性能实验.结果表明,膜层由过渡层、致密层和疏松层3层组成.其相组成主相为Al2TiO5,其次为Al2SiO5,并含有少量无定型SiO2.膜层的维氏硬度为8 470 MPa,是基体硬度的2倍多.采用45#钢作对磨副,载荷为5 kg,磨损时间20 min条件下,膜层的失重为0.25 mg,仅为基体的8%左右.     

Reward-based voltage scheduling for dynamic-priority hard real-time systems

Reward-based scheduling has been investigated for flexible applications in which an approximate but timely result is acceptable. Meanwhile, significant research efforts have been made on voltage scheduling which exploits the tradeoff between the processor speed and the energy consumption. In this paper, we address the combined scheduling problem of maximizing the total reward of hard real-time systems with a given energy budget. We present an optimal off-line algorithm and an efficient on-line algorithm for jobs with their own release-times/deadlines under Earliest-Deadline-First (EDF) scheduling. Experimental results show that the solution computed by the on-line algorithm is no more than 14% worse than the theoretical optimal solution obtained by the optimal off-line algorithm. This research was supported by the MIC (Ministry of Information and Communication), Korea, under the ITRC (Information Technology Research Center) support program supervised by the IITA (Institute of Information Technology Assessment). A preliminary version of this article was presented at Real-Time and Embedded Computing Systems and Applications (RTCSA’04).