An Initial Experimental Assessment of the Dynamic Modelling in UML

The goal of this empirical study is to compare the semantic comprehension of three different notations for representing the dynamic behaviour in unified modelling language (UML): (a) sequence diagrams, (b) collaboration diagrams, and (c) state diagrams. Eighteen students of Informatics analysed the three types of diagrams within three different application domains. We performed a 3 × 3 factorial experimental design with repeated measures. The metrics collected were total time and total score. The main conclusion of this study is that the comprehension of the dynamic modelling in object-oriented designs depends on the diagram type and on the complexity of the document. The software project design written in the UML notation is more comprehensible, when the dynamic behaviour is modelled in a sequence diagram. While if it is implemented using a collaboration diagram, the design turns out to be less comprehensible as the application domain, and consequently, the document is more complex.     

Total Volatile Organic Compounds (TVOC) in Indoor Air Quality Investigations*

Abstract The amount of volatile organic compounds (VOCs) in indoor air, usually called TVOC (total volatile organic compounds), has been measured using different definitions and techniques which yield different results. This report recommends a definition of TVOC referring to a specified range of VOCs and it proposes a method for the measurement of this TVOC entity. Within the specified range, the measured concentrations of identified VOCs (including 64 target compounds) are summed up, concentrations of non-identified compounds in toluene equivalents are added and, together with the identified VOCs, they give the TVOC value. The report reviews the TVOC concept with respect to its usefulness for exposure assessment and control and for the prediction of health or comfort effects. Although the report concludes that at present it is not possible to use TVOC as an effect predictor, it affirms the usefulness of TVOC for characterizing indoor pollution and for improving source control as required from the points of view of health, comfort, energy efficiency and sustainability.     

A parallel implementation of Flat Concurrent Prolog

Flat Concurrent Prolog is a simple, practical, concurrent programming language which has an efficient uniprocessor implementation. This paper describes an initial parallel implementation of the language; it consists of an interpreter implemented on an Intel iPSC Hypercube. The parallel execution of concurrent logic programming languages involves many nontrivial implementation problems. Some of these problems are well known and have been treated extensively in the literature. The most difficult task is to integrate problem solutions in a coherent and efficient manner. The algorithm presented has been useful in providing insights into the major problems and includes a number of novel ideas to simplify implementation. It does not attempt to solve all the problems involved but rather provides a workable basis for current and future research. The algorithm is under ongoing refinement, simplification and improvement.     

汾河二库建设中监理抽检的作用

本文阐述了汾河二库监理部现场抽样检验的工作内容、数据的统计分析及管理制度，提出了建立健全监理现场抽检的必要性。     

Two minimum spanning forest algorithms on fixed-size hypercube computers

Two parallel algorithms for finding minimum spanning forest (MSF) of a weighted undirected graph on hypercube computers, consisting of a fixed number of processors, are presented. One algorithm is suited for sparse graphs, the other for dense graphs. Our design strategy is based on successive elimination of non-MSF edges. The input graph is partitioned equally among different processors, which then repeatedly eliminate non-MSF edges and merge results to gradually construct the desired MSF of the entire graph. Low communication overhead is achieved by restricting the message-flow to between the neighboring processors in the hypercube topology. The correctness of our approach is due to a theorem which states that with total-ordered edges, if an edge of an arbitrary subgraph does not belong to its MSF, then it does not belong to the MSF of the entire graph. For a graph of n vertices and m edges, our first algorithm finds an MSF in O(m log m)/p) time using p processors for p ≤ (mlog m)/n(1+log(m/n)). The second algorithm, efficient for dense graphs, requires O(n²/p) time for p≤n/log n.     

十阶拉丁方的正交对的一个系列

本文给出了5个AR矩阵,由每个AR矩阵可以构造4对十阶正交拉丁方,它们组成一个完整的系列。     

Mixed size tournament selection

 In genetic algorithms, tournament schemes are often applied as selection operators. The advantage is simplicity and efficiency. On the other hand, major deficiencies related to tournament selection are the coarse scaling of the selection pressure and the poor sampling accuracy. We introduce a new variant of tournament selection which provides an adjustable probability distribution, a fine-tuning facility for the selection pressure and an improved sampling accuracy at the cost of a minimal increase of the complexity and with almost no loss of efficiency.     

Noise amplification analysis and comparison of two periodic nonuniform sampling reconstruction methods used in DPCA SAR

General Sampling Expansion Reconstruction Method （GSERM） and Digital Spectrum Reconstruction Method （DSRM）, which prove effective to reconstruct azimuth signal of Displaced Phase Center Apertures （DPCA） Synthetic Aperture Radar （SAR） system from its Periodic Non-Uniform Sampling （PNUS） data sequences, would amplify the noise and sidelobe clutter simultaneously in the reconstruction. This paper formulates the relation of the system transfer matrixes of the above two methods, gives the properties, such as periodicity, symmetry, and time-shift property, of their Noise and Sidelobe Clutter Amplification Factor （NSCAF）, and discovers that DSRM is more sensitive than GSERM in the white noise environment. In addition, criteria based on initial sampling point analysis for the robust PRF selection are suggested. Computer simulation results support these conclusions.     

煤矿井下复杂顶板巷道支护工艺研究与应用

针对新村煤业13111上顺槽掘进巷道顶底板软岩巷道顶板变形严重、支护困难等问题,通过从理论研究、取样分析、现场测试等方面进行研究,在此研究的基础上对原巷道施工断面、锚杆索支护参数、支护工艺等进行优化改进。经现场应用及测试结果显示,采用优化后的支护方案后,巷道围岩变形得到有效控制,工作面实现了安全高效回采。     

基于响应面法的某防护结构优化设计

为提高某防护型驾驶室底部类V形防护结构对爆炸冲击波的防护性能,利用尺寸优化和形状优化相结合的设计方法,进行了防护结构的优化设计。首先通过拉丁超立方试验设计建立了中心防护板最大位移和模型总质量的高精度响应面;再综合考虑板件厚度和边界形状的变化范围以及安全性和轻量化要求,运用可行方向优化算法对建立的响应面进行了求解计算,得到了一组最优值。结果表明优化后防护结构的防护性能得到了显著提升,为更多防护结构的设计提供了参考依据。