程序复杂性度量

本文力图阐明程序复杂性度量的有关定义、研究内容、技术和方法,并探讨它用软件产品的质量、交付的时间和费用的关系以及它在软件开发中的作用。

基于拓扑结构的程序复杂性度量研究

基于程序拓扑结构,分析传统McCabe复杂性度量法,提出封闭区域个数统计法和判定结点个数统计法两种快速、直观、简便的计算方法,并提出路径复杂度算法,由此定义判定树类拓扑结构程序以路径数即分支数作为程序复杂度,同时提出了降低复杂度的程序设计方法,以实例进行对比验证,实践证明该方法简单、可行、有效.

土地质量及其度量初步研究

土地质量研究是全球变化研究的前沿与热点,是土地利用/土地覆被变化(LUCC)研究的重要内容.界定土地质量的概念,研究土地质量变化,建立土地质量度量标准,具有重要的科学意义.土地质量是一个综合概念,是与农业生产、林业生产、环境保护与管理等各种土地利用的需求相关的土地条件.其内涵应该包括3部分,即土地的生态环境质量、土地的经济质量和土地的管理质量.土地的生态环境质量是指土地的自然属性和环境状况;土地的经济质量指土地的经济属性,反映土地的产出能力和区位条件;土地的管理质量是指土地的社会属性,反映人类活动对土地的影响.最后,提出了土地质量度量程序和土地质量度量指标体系框架.

浅谈软件度量

介绍软件工程学的一个重要分支——软件度量。包括软件度量的定义,软件度量在现代软件过程中的作用,软件度量的过程和相关的活动。

一类链状图的枚举特征

在并发程序复杂性度量研究中,作者曾定义了所谓B图,用以作为Ada并发程序中一种会合关系的模型.该文研究B图的一种特殊情况—BB图,一类链状图.n节点BB图是在n个节点、高为n-1的有向树上再添加若干条边,其约束条件是:每个节点的入度不大于二,每个节点的出度也不大于二.该文给出BB图图的若干若干枚举特征,并指出这些特征同第二类Stirling数的密切关系.

BB图的枚举特征

在并发程序复杂性度量研究中,我们曾定义了一种B图,用以作为Ada并发程序中一种会合关系的模型。我们将B图推广到BB图。n节点BB图是在n个节点的串联树上再添加若干条边,其约束条件是:每个节点的入度不大于二,每个节点的出度也不大于二。给出BB图的若干若干枚举特征,指出同第二类Stirling数的密切关系。

Effect of Relative Humidity on Catalytic Combustion of Toluene over Copper Based Catalysts with Different Supports

The copper based catalysts, CuO/T-Al2O3, CuO/y-Al2O3-cordierite （Cord） and CuO/Cord, were prepared by impregnation method. The catalytic activity of the catalysts was tested in absence and presence of water vapor,and the catalysts were characterized. Temperature program desorption （TPD） experiments or toluene and water on the catalysts were carried out. The influence of water vapor on the activity of the catalysts was discussed. Results showed that addition of the water vapor has a significant negative effect on the catalytic activity of the catalysts.The higher the concentration of the Water vapor in feed steam was, the lower the catalytic activity of the copper based catalysts became, which could be mainly ascribed to the competition of water molecules with toluene molecules for adsorption on the catalyst surfaces. TPD experiments showed that the strength of the interaction between water molecules and three catalysts followed the order： CuO/γ-Al2O3〉CuO/γ-Al2O3-Cord〉CuO/Cord. As a consequence of that, the degree of degradation in the catalytic activity of these three catalysts by the water vapor followed the order： CuO/γ-Al2O3〉CuO/y-Al2O3-Cord〉CuO/Cord. However, the negative effect of the water vapor was reversible.

QoS Routing Algorithm with Multi-Dimensions for Overlay Networks

Overlay networks have emerged as a useful approach to providing a general framework for new applications and services that are to be implemented without significantly changing the IP-layer network infrastructure.Overlay routing has been used as an alternative to the default best effort Internet routing for the absence of end-to-end Quality of Service(QoS). While the former has recently been investigated, the conflict of QoS restraints and resource optimization remains unsolved. Recent studies have shown that overlay paths can give better latency, loss rate and TCP throughput. In this paper, a multi-dimensional QoS objective model based on the analysis of multiple QoS constraints has been presented, and a routing algorithm to optimise the overlay resource of its nodes and links is then proposed.In fact, the algorithm obtained multiple QoS values using probability theory to achieve the routing according to the multi-dimensional QoS objective vector of the QoS objective model. Simulation results reveals that the algorithm works better than other existing algorithms in balancing the network resources, and applications with stringent QoS requirements could be run.

LO-RAY-LIGH@ Diffraction Gratings in UV-VIS Spectroscopy

It has been more than half a century since the release of the first Shimadzu UV-VIS （UV-visible） spectrophotometer QB-50 in 1952, and during this time more than 160,000 UV-VIS spectrometers have been produced and installed in a wide variety of different applications. A lot of technical innovations have been implemented to improve the performance and significantly reduce the stray light levels. The latest innovation during development of sophisticated spectrophotometers is based on a new holographic exposure method and optimized etching process which has made it possible to produce both high-efficient and exceptionally low stray light gratings. These LO-RAY-LIGH~ gratings have guaranteed values of stray light at the intermediate position between zero-order and first-order lights. The values are measured by Shimadzu＇s laser stray-light-measuring system. The latest development in the series of UV-VIS spectrophotometers is the UV-2700 which is a true double beam double monochromator system in a compact design for high-precision spectral analysis of a wide range of samples including organic and inorganic compounds, biological samples, optical materials and photovoltaics. The high performance optical system is designed with ＂LO-RAY-LIGH＂ diffraction gratings, featuring highest efficiency and exceptionally low stray light. The spectrophotometer operates in the wavelength range from 185 nm to 900 nm and allows highly sophisticated applications such as direct measurement of high density samples up to 8 absorbance units without dilution.

Development of Online Machining and Measurement System in Die and Mold Manufacturing： Concept and Fundamental Experiments

The corrective machining to compensate the resulting errors is usually tried at plural times based on the trial-and-error process when the machining is realized in die and mold manufacturing. This corrective machining has an influence on accuracy and efficiency and is an important factor. The measurement system for measuring the forms of die and mold at all times is essential in order to machine the die and mold with high accuracy and efficiency. However, the problems of management and operation errors are found in compensating process of die and mold machining. In this paper, an online machining and measurement system in die and mold manufacturing is developed in order to overcome these problems. In this online system, 2-axis control system is added to a surface roughness measuring instrument, and both NC machining program and measured data are linked and controlled using a same computer. Therefore, the machining and measurement can be recognized for consistent process, and can be realized on the machine. This system has the advantages such as the high accuracy, low-price, and online convenience and so on. The possibility of practical use of this online system was investigated by fundamental experiments.

Automatically Mining Application Signatures for Lightweight Deep Packet Inspection

Automatic signature generation approaches have been widely applied in recent traffic classification.However,they are not suitable for LightWeight Deep Packet Inspection(LW_DPI) since their generated signatures are matched through a search of the entire application data.On the basis of LW_DPI schemes,we present two Hierarchical Clustering(HC) algorithms:HC_TCP and HC_UDP,which can generate byte signatures from TCP and UDP packet payloads respectively.In particular,HC_TCP and HC_ UDP can extract the positions of byte signatures in packet payloads.Further,in order to deal with the case in which byte signatures cannot be derived,we develop an algorithm for generating bit signatures.Compared with the LASER algorithm and Suffix Tree(ST)-based algorithm,the proposed algorithms are better in terms of both classification accuracy and speed.Moreover,the experimental results indicate that,as long as the application-protocol header exists,it is possible to automatically derive reliable and accurate signatures combined with their positions in packet payloads.

Concentration–discharge patterns of weathering products from global rivers

Quantifying the functional relationships relating river discharge and weathering products places key constraints on the negative feedback between the silicate weathering and climate. In this study we analyze the concentration–discharge relationships of weathering products from global rivers using previously compiled time-series datasets for concentrations and discharge from global rivers. To analyze the nature of the covariation between specific discharge and concentrations, we use both a power law equation and a recently developed solute production equation. The solute production equation allows us to quantify weathering efficiency, or the resistance to dilution at high runoff, via the Damkohler coefficient. These results are also compared to those derived using average concentration–discharge pairs.Both the power law exponent and the Damkohler coefficient increase and asymptote as catchments exhibit increasingly chemostatic behavior, resulting in an inverse relationship between the two parameters. We also show that using thedistribution of average concentration–discharge pairs from global rivers, rather than fitting concentration–discharge relationships for each individual river, underestimates global median weathering efficiency by up to a factor of ～10. This study demonstrates the utility of long time-series sampling of global rivers to elucidate controlling processes needed to quantify patterns in global silicate weathering rates.

Variable Selection Procedures in Linear Regression Models with Screening Consistency Property

There are two fundamental goals in statistical learning： identifying relevant predictors and ensuring high prediction accuracy. The first goal, by means of variable selection, is of particular importance when the true underlying model has a sparse representation. Discovering relevant predictors can enhance the performance of the prediction for the fitted model. Usually an estimate is considered desirable if it is consistent in terms of both coefficient estimate and variable selection. Hence, before we try to estimate the regression coefficients β , it is preferable that we have a set of useful predictors m hand. The emphasis of our task in this paper is to propose a method, in the aim of identifying relevant predictors to ensure screening consistency in variable selection. The primary interest is on Orthogonal Matching Pursuit（OMP）.

Variation of Sediment Concentration and Its Drivers Under Different Soil Management Systems

In order to prevent soil erosion in southern China,a study was performed to determine the drivers of sediment concentration variation using simulated rainfall and four soil management systems under field condition.Four soil management systems,i.e.,forest and grass coverage(FG),forest coverage with disturbed soil surface(FD),contour tillage(CT) and downslope tillage(DT),were exposed to two rainfall intensities(40 and 54 mm h-1) using a portable rainfall simulator.The drivers of sediment concentration variation were determined by the variations of runoff rate and sediment concentration as well as their relationships.The effects of the four soil management systems in preventing water and soil losses were compared using runoff rates and sediment concentrations at steady state.At runoff initial stage,sediment concentration variation was mainly driven by rainfall and management.The degree of sediment concentration variation driven by flow varied with different soil management systems.Three best relationships between runoff rate and sediment concentration were identified,i.e.,reciprocal(CT),quadratic(FG and FD) and exponential(DT).At steady state,runoff rates of the four soil management systems varied slightly,whereas their sediment concentrations varied greatly.FG and CT were recommended as the best soil management systems for preventing water and soil losses.

Navigation using binary pulsars

The issue of navigation using binary pulsars is investigated in this paper.We show how the effect of the binary motion is incorporated in the navigation measurement equation.Necessary reference systems and time scales are introduced and the transformation between different time scales is derived.Based mainly on Damour and Deruelle's binary model and the TEMPO2 software,the timing model resolving the time delay from emission to arrival is established with the solar system,interstellar and binary system delays included,which retains all the terms exceeding 1 ns.The navigation measurement equation is thus built and the parameters needed are listed.A comparison is made between Sheikh's measurement equation and that in this paper.It is found that it is not necessary to introduce a fictitious SSB arrival time as Sheikh does.Near-Earth navigation for the Keplerian orbit in the case of observing one pulsar is investigated.The uncertainties of the orbit parameters are derived using the least square fitting method,which reveals that observing one pulsar enables one to navigate near-Earth spacecraft.

Complete Ricci solitons on Finsler manifolds

The geometric flow theory and its applications turned into one of the most intensively developing branches of modern geometry. Here, a brief introduction to Finslerian Ricci flow and their self-similar solutions known as Ricci solitons are given and some recent results are presented. They are a generalization of Einstein metrics and are previously developed by the present authors for Finsler manifolds. In the present work, it is shown that a complete shrinking Ricci soliton Finsler manifold has a finite fundamental group.

Ferroelectric materials for vibrational energy harvesting

Energy harvesting is an appealing technology that makes use of the ambient energy which is otherwise wasted. Piezoelectric materials directly convert the elastic energy to the electric energy, and thus have a great advantage in scavenging vibrational energy for simplicity in device structure with relatively high power density. This paper provides an overview on the research of piezoelectric materials in energy harvesting in recent decades, from basics of piezoelectricity and working principle of energy harvesting with piezoelectric materials, to the progress of development of high-performance piezoelectrics including ceramics, single crystals and polymers, then to experimental attempts on the device fabrication and optimization, finally to perspective applications of piezoelectric energy harvesting(PEH). The criteria for selection of materials for PEH applications are introduced. Not only the figure of merit but also maximum allowable stress of materials are taken into account in the evaluation of their potential in achieving high energy density and output power density. The influence of the device configuration on the performance is also acknowledged and discussed. The magnitude and distribution of induced stress in the piezoelectric unit upon excitation by the vibration source play an important role in determining the output power density and can be tuned via proper design of device configuration without changing its resonant frequency. Approaches to address the issue of frequency match accompanying with the resonant mode are illustrated with literature examples. Usage of PEH devices can be extended to a variety of vibration sources in everyday life as well as in nature. Some appealing applications of PEH, such as in implantable and wearable devices, are reviewed.