AN ALGORITHM FOR AUTOMATICALLY GENERATING BLACK-BOX TEST CASES

Selection of test cases plays a key role in improving testing efficiency. Black-box testing is an important way of testing, and its validity lies on the selection of test cases in some sense. A reasonable and effective method about the selection and generation of test cases is urgently needed. This letter first introduces some usualmethods on black-box test case generation,then proposes a new algorithm based on interface parameters and discusses its properties, finally shows the effectiveness of the algorithm.

使用C语言编程的安全性分析

为了避免C语言编程中出错,保障程序的安全性,从内存泄漏、指针有效性、数组超界几方面进行深入分析,找出造成程序运行时产生不安全问题的原因,给出解决方案。

Deformation prediction and analysis of underground mining during stacking of dry gangue in open-pit based on response surface methodology

Deformation prediction and the analysis of underground goaf are important to the safe and efficient recovery of residual ore when shifting from open-pit mining to underground mining.To address the comprehensive problem of stability in the double mined-out area of the Tong-Lv-Shan(TLS)mine,which employed the dry stacked gangue technology,this paper applies the function fitting theory and a regression analysis method to screen the sensitive interval of four influencing factors based on single-factor experiments and the numerical simulation software FLAC3D.The influencing factors of the TLS mine consist of the column thickness(d),gob area span(D),boundary pillar thickness(h)and height of tailing gangue(H).The fitting degree between the four factors and the displacement of the gob roof(W)is reasonable because the correlation coefficient(R2)is greater than0.9701.After establishing29groups that satisfy the principles of Box-Behnken design(BBD),the dry gangue tailings process was re-simulated for the selected sensitive interval.Using a combination of an analysis of variance(ANOVA),regression equations and a significance analysis,the prediction results of the response surface methodology(RSM)show that the significant degree for the stability of the mined-out area for the factors satisfies the relationship of h>D>d>H.The importance of the four factors cannot be disregarded in a comparison of the prediction results of the engineering test stope in the TLS mine.By comparing the data of monitoring points and function prediction,the proposed method has shown promising results,and the prediction accuracy of RSM model is acceptable.The relative errors of the two test stopes are1.67%and3.85%,respectively,which yield satisfactory reliability and reference values for the mines.

Critical Fujita Exponents for Localized Reaction Diffusion Systems

In this paper, we prove the existence of cirtical Fujita exponents for a class of localized reaction diffusion systems.

Self-Organized Criticality Analysis of Earthquake Model Based on Heterogeneous Networks

The original Olami-Feder-Christensen （OFC） model, which displays a robust power-law behavior, is a quasistatic two-dimensional version of the Burridge-Knopoff spring-block model of earthquakes. In this paper, we introduce a modified OFC model based on heterogeneous network, improving the redistribution rule of the original model. It can be seen as a generalization of the originM OFC model We numerically investigate the influence of the parameters θandβ, which respectively control the intensity of the evolutive mechanism of the topological growth and the inner selection dynamics in our networks, and find that there are two distinct phases in the parameter space （θ,β）. Meanwhile, we study the influence of the control parameter a either. Increasing a, the earthquake behavior of the model transfers from local to global.

Linear Combination of Derivative Weighted Composition Operators

The relation between composition operators on the Dirichlet spaces in the open unit disk and derivative weighted composition operators on the Bergman spaces in the open unit disk is investigated firstly,and for a combination of several derivative weighted composition operators which acts on classic Bergman space,the lower bound of its essential norm is estimated in terms of the boundary data of the symbols of d-composition operators.Some similar results about composition operators on the Dirichlet space are also presented.A necessary condition is given to determine the compactness of the combination of several derivative weighted composition operators on Bergman spaces.

Availability and Potability of Alternative Domestic Water in an African City： The Case of Harare, Zimbabwe

A study was carried out between November 2010 and April 2011 to assess the availability and potability of water from alternative water sources in Harare, Zimbabwe＇s capital city. A survey of 256 households from a total of 10 high, medium and low income suburbs and informal settlements was undertaken to assess types and amount of water consumed. This was complemented by a water quality study that assessed a selection of physical, chemical and bacteriological parameters. Quality of the water was compared to World Health Organisation and Zimbabwean standards. All households were found to rely on water sources other than municipal water. Per capita water consumption across settlements was found to be below the recommended upper limit of 50 litres per person per day except in one high income suburb, but above the recommended lower limit of 15 litres. All samples were within the acceptable limit for color but above the acceptable limit for turbidity. Chemical parameters were found to be within the acceptable range except for total hardness, where 35% of the samples were above the acceptable range. About a third of the samples from low income suburbs and informal settlements were above the acceptable limit for faecal and total coliforms.

More on Convering Squares with Squares

This paper improves some lower bounds of a function f(x) introduced in the problem of covering squares with squares.

Analysis on gust factor of tropical cyclone strong wind over different underlying surfaces

Based on one year gradient wind data and the wind data of a strong typhoon observed by three meteorological towers located on the coast and at the inshore sea,the underlying surfaces of the meteorological towers were classified and the roughness lengths were calculated quantitatively.On the basis of strong wind characteristic representative assessment and sample selection on the wind data of strong typhoon Hagupit,the gust factor variation characteristics of tropical cyclones under different underlying surfaces were analyzed.The observed fact and variation rule were found as follows:1) The roughness lengths under neutral atmospheric condition which were calculated using logarithmic wind profile fitting based on the observation data can describe the slight change of the underlying surface objectively.2) The gust factor of strong typhoon wind didn't have variation trends with wind speed.But the variation amplitude of the gust factor was rather large over rough underlying surface which had pronounced effect on the numerical design of structural engineering.3) The variation of the gust factor with height satisfied power law or logarithmic law.The power law fitting was more suitable for smooth underlying surface while the logarithmic fitting was better over rough underlying surface.4) The observation data also suggested that the relationship between gust factor and roughness length can be described by power or linear equation.5) The gust factor observed in this typhoon case was different from the gust factor recommended by WMO:The gust factor of the offshore wind came from rough underlying surface was higher than the value recommended by WMO while the gust factor of the onshore wind came from smooth underlying surface is less than the WMO recommended value.

Existence and asymptotic properties of solutions to elliptic systems involving multiple critical exponents

This paper is concerned with a singular elliptic system, which involves the Caffarelli-Kohn-Nirenberg inequality and multiple critical exponents. By analytic technics and variational methods, the extremals of the corresponding bet Hardy-Sobolev constant are found, the existence of positive solutions to the system is established and the asymptotic properties of solutions at the singular point are proved.

Multiple solutions for weighted nonlinear elliptic system involving critical exponents

In this paper, by using the idea of category, we investigate how the shape of the graph of h（x） affects the number of positive solutions to the following weighted nonlinear elliptic system： = （ N-2-2a 2. where 0 is a smooth bounded domain in ]1N （N 〉 3）, A, cr 〉 0 are parameters, 0 ≤ μ 〈 μa a 2 ＇ h（x）, KI（X） and K2（x） are positive continuous functions in , 1 〈 q 〈 2, a, β 〉 1 and a ＋ β = 2＊（a,b） （2＊ （a, b） 2N = N-2（1＋a-b） is critical Sobolev-Hardy exponent）. We prove that the system has at least k nontrivial nonnegative solutions when the pair of the parameters （）, r） belongs to a certain subset of N2.

Resurrected From the Past

China has a new spot on the UNESCO World Heritage ListThree sites of the Tusi heritage—areas resided in by ethnic minorities in southwest and central China from the 13th century to the mid-20th century—were added to the list of the UNESCO World Heritage Sites in July,increasing the number of the country’s World Heritage Sites to 48,the second largest in the world following Italy.